Page 1 This manual describes LA100 software version V6.7. Please refer to any accompanying update sheets if your LA100 displays a version number later than this when it is turned on or reset. Users familiar with earlier software should refer to appendix I.3 for a list of new features.
Page 2: Table Of Contents
Contents 1.0 Introduction 1.1 Viewing Angle 1.2 Switching-On 1.3 The Keyboard 1.4 Reset 1.5 Memory Clear and Non-Volatile Memory 1.6 The Configuration Menu 1.7 Connectors 1.8 Technical Support 2.0 Manual Operation 2.1 Volume Control 2.2 Generating Tones 2.3 Measuring Tones 2.4 Channel Switching 2.5 Programmable Presets and Initial Settings 2.6 Relative Levels −...
Page 3 3.0 Sequence Testing 3.1 Running a Sequence 3.2 Page Results Mode 3.3 Frequency Response Results 3.4 Printing Sequence Results 3.5 Storing Results in Memory 3.6 Cyclic Identification Character 3.7 Test Level 3.8 Input Level 3.9 Ch oosing a Sequence 3.10 Interpreting Sequence Results 3.11 Single Channel Operation 3.12 Single Register Operation 3.13 FSK Failure −...
Page 4 4.11 Wow & Flutter Segment (W) 4.12 Phase Segments (Y, Z, z) 4.13 User Level Segment (K) 4.14 Maximum Output Level (MOL) Segments (H, h) 4.15 Difference Frequency Distortion (d) 4.16 Tone Burst/Tones Segment (!) 4.17 Repeating Segments and Sequences (<) 4.18 Multiple Results Compartments 4.19 Selecting a Tolerance (±) 4.20 Output Impedance Segment (%)
Page 5 8.7 Epson LQ and Other 24 Pin Printers 8.8 Inkjet Printers 8.9 Portable Printers 8.10 Printer Problems 9.0 Remote Control 9.1 Connecting the LA100 to a Computer 9.2 The RS232 Serial Data Format 9.3 Entering Remote Mode 9.4 Command Format 9. 5 Some Examples 9.6 Hints on Writing Programs...
Page 6 10.14 Display Faults 10.15 Replacing Boards 10.16 Spares 10.17 LA101 Loudspeaker Appendix A Accessories A.1 Items Supplied with the LA100 A.2 Computer Support Software A.3 Conversion Kits (Rack Mount/Separate) Appendix B Audio Sockets B.1 Rear XLR Connectors B.2 Front Jack Sockets B.3 BNC Sockets...
Page 7 Appendix G LA102 Filter Graphs Appendix H FSK Header Format Appendix I LA100 Versions I.1 LA100 History I.2 Upgrading Early Units I.3 Software Changes I.4 Rack Mounted Unit (LA100R) I.5 CCITT O.41 Filter Version (LA100C) I.6 Power Supply Monitoring (LA100P) I.7 Telecom Australia Version (LA100T)
Page 9: Introduction
LA100 Audio Analyser. The LA100R is a rack mount version of the LA100 consisting of the LA101 and LA102 bolted together, side by side, to go into a 19" rack.
Page 10: The Keyboard
When turned on, or after a reset, the state of both units is determined by their configuration settings stored in non-volatile memory. As supplied, or following removal of the battery, configurations are set to the Lindos default settings, but these can be changed using the configuration menu described below. In default configuration the LA101 generates 0dBu (0.775V) at 1kHz and the LA102 goes into its flat level-...
Page 11: Memory Clear And Non-Volatile Memory
In case of doubt, a complete reset will restore Lindos default conditions. Press (ie hold and press on either unit and a menu will appear (fig 1.2), with the following options:...
Page 12: The Configuration Menu
Keys , and (representing 6 to 10) can also be used to set the various options and will restore the Lindos/Recommended default option. Exit the menu by resetting or pressing The current LA102 configuration settings can be printed by pressing when the configuration menu is displayed (see sections 8.1 &...
Page 13 1. Introduction LA101 Configurations: Sequence bank User, Lindos, Tape, Speaker, Filter, Meter, Utility, BBC, BT, Telecom Australia, SAPO Frequency display Rounded, true R Remote baud rate 75, 150, 300, 1200, 2400, 4800, 9600, 110 Start up level MUTE, p/set 1, p/set 2, p/set 3, p/set 4, p/set 5, previous...
Page 14: Technical Support
(see fig. 1.1). In the event of a unit developing a fault, Lindos can often diagnose the problem by telephone or fax and forward any necessary parts the same day, but please refer to the service information in chapter 10 first.
Page 15: Manual Operation
Functions The first-time user is advised to link the XLR sockets on the rear of the units and run some of the measurements described below in order to gain familiarity with the LA100. 2.1 Volume Control volume monitor loudspeaker The LA102 is fitted with an internal loudspeaker which allows the user to monitor the signal after the filter and gain stages of the LA102.
Page 16: Measuring Tones
2. Manual Operation the frequency to be stepped up or down between 5Hz and 31.5kHz in convenient one- third octave steps. For finer control (32 steps per octave) hold the key while operating these keys (see appendix F for a full list of frequencies). Two keys marked allow similar adjustment of output level between -100dB and +26dBu in 1dB steps, or 0.01dB steps with the key held.
Page 17 2. Manual Operation autoranging; the bar graph scale changing in 10dB steps when the reading goes outside ±6dB of the centre. This leaves a ‘guard band’ of 2dB so that no reasonably steady signal should cause the range to ‘hunt’ up and down. On wildly varying signals, though, manual range setting may be found useful, and the keys on the LA102 change the range, automatically disabling autoranging.
Page 18: Channel Switching
2. Manual Operation 2.4 Channel Switching Channel switching on the LA102 selects input channel (displaying ‘ ’ or ‘ ’ on the screen). the LA101 cycles through ‘L+R’, ‘L’ and ‘R’ channels, while mutes both channels and displays ‘ ’. Pressing again will restore the selected channel state (‘...
Page 19: Measurement Options
2. Manual Operation ), cancels the test level. Note that the level difference between the two channels can be measured easily by setting the test level on one and then selecting the other. The same key combination, , on the LA102 stores the current reading and subsequent readings are shown relative to this on the numerical readout.
Page 20: Measurement Options
2. Manual Operation LEVEL CROSSTALK RMS, 2-100kHz 100Hz narrow band, RMS RMS, 22-22kHz 315Hz narrow band, RMS VU 22-22kHz 1kHz narrow band, RMS Twin level and phase bar graphs 6.3kHz narrow band, RMS PPM 22-22kHz 10kHz narrow band, RMS VU, A weighted 40Hz narrow band, RMS RMS, A weighted 150-300Hz narrow band, RMS...
Page 21: Frequency Measurement
2. Manual Operation Fig. 2.7 Level options 1-5 Fig. 2.8 Noise Options 6-10 2.8 Frequency Measurement Frequency measurement Aliasing on frequency measurement Frequency range The LA102 displays the measured input frequency (of the selected channel) on all level measurements (fig. 2.2). To measure frequency the LA102 times zero-crossings over a variable number of cycles and calculates frequency −...
Page 22: Noise Measurement
2. Manual Operation operates on the channel with the greatest level although manual range changing still works normally. Difference between the two channels Fig. 2.9 Dual Level & Phase Bars Fig. 2.10 Noise Measurement 2.10 Noise Measurement Noise measurement A weighted noise CCIR weighting filter CCIR468-3 Mute Noise is normally measured using the widely accepted CCIR468-4 weighted measurement (identical to CCIR468-1 to 3 but with different tolerances) which is provided on noise option 1.
Page 23: Rumble Measurement
2. Manual Operation 2.11 Rumble Measurement Measuring rumble Gramophone systems Turntable rumble may be measured by selecting Noise Option 5 (weighted) or 4 (unweighted). Both rumble measurements have the same HF roll-off above 315Hz but the weighted measurement also rolls off below 315Hz to give a measure of the subjective intrusion of rumble (see appendix G).
Page 24: Distortion Measurement
Note that a crosstalk reading around 0dB usually indicates that the channels are transposed. Note: The LA100 can measure crosstalk at levels of -100dB or lower and this is usually good enough for all practical purposes. However, a few users have demanded even lower residual crosstalk levels and Lindos has devised a way of reducing the LA102’s own...
Page 25: Wow And Flutter Measurement
2. Manual Operation relative level of distortion is displayed numerically, in dB and percent while the bar graph shows the absolute level in dBu. Unlike most instruments the LA102 uses a multi-stage bandstop-plus-highpass filter to reject the fundamental, and no nulling process is involved.
Page 26: Speed Measurement
2. Manual Operation suggest is much more manageable than the usual ‘point nought five per cent’ (-66dB) and should become established practice; as is tending to happen with distortion figures. However, for the less daring, a digital percentage conversion is also displayed! A signal level of -20 to +10dB is recommended for flutter measurement, but the unit does in fact constantly monitor the signal level and frequency and display if either goes...
Page 27: Difference Frequency Distortion Measurement
2. Manual Operation 2.16 Difference Frequency Distortion Measurement Several other miscellaneous measurements are provided on the key, and one of these is 2nd order difference frequency distortion. This is a form of intermodulation distortion (IMD) similar to the CCIF IMD measurement which has now been superseded by the IEC268-3 standard.
Page 28 2. Manual Operation Level/dB Test Signal (f1 and f2) f2-f1 2nd order product 2f1-f2 product 2f2-f1 product f1+f2 product 1000 1500 2000 Frequency/Hz Fig. 2.15 Typical Intermodulation Products from a Double Tone with 1kHz Centre Frequency, and 70Hz Separation (Nominally) Output V Time/ms Fig.
Page 29: Quantising Distortion (Qd) Measurement
2.17 Quantising Distortion (QD) Measurement The LA100 system measures quantising distortion on a 40Hz tone by notching out the fundamental, and rejecting low harmonics with a 400Hz high-pass filter to leave only high frequency components, which are then measured in one of two ways. W&F option 4 reads rms with 22kHz bandwidth, option 3 uses CCIR weighting and quasi-peak detection.
Page 30: Standards
2. Manual Operation component of motion along the groove equivalent to flutter. This can be measured using W&F option 8 which selects a flutter measurement with special filtering to read only flutter components around 300Hz (3.15kHz and 315Hz tones can also be used). The measurement is normally made using a test disc to DIN45542 and complies with the current ITC (IBA) requirement (DIN45411).
Page 31: Dbu, Dbv, Volts And Power Measurement
2. Manual Operation corrects the output to give the displayed power in dB(1mW), indicated by dBm, into a 600 load for any selected output impedance. Note that 10 output impedance should always be selected on the LA101 when the rear XLR sockets are being used, and that 75 or 600 should be selected when the front jack sockets are being used.
Page 32 2. Manual Operation absolute output level in Volts (after taking the test level into consideration, but before the weightings and impedance corrections are added). Fig. 2.20 dBu and Volts Fig. 2.21 dBV and Volts The LA102 normally displays the measured voltage in dB relative to 0.775V, or dB(0.775V), indicated by the symbol dBu, with 10k input impedance.
Page 33: Printing The Displayed Values
2. Manual Operation load 100W 100W LA102 AUDIO MEASURING SET Power Dummy Divide LA102 Measuring Set Amplifier load by 10 (configuration W2 set) Fig. 2.22 Using an 8 Dummy Load and Attenuator for Power Measurement 2.23 Printing the Displayed Values Printing displayed values in manual mode Printing The LA102 can print the measured frequency, level and phase which are displayed on the LCD.
Page 34: Miscellaneous Features
2. Manual Operation generated with the same rms level as sine waves (ie less peak to peak amplitude). The peak to peak amplitude of sawtooth and triangular waveforms is the same as that for sinusoids at the same level setting (so the rms level is 1.7dB lower). SAW+ and SAW- provide sawtooth waveforms with positive and negative going slopes.
Page 35: La101 Weighting Curves
2. Manual Operation tone testing. 2.26 LA101 Weighting Curves CCIR468 inverse Oscillator weighting User weighting curves Pre-emphasis on the LA101 cycles round weighting curves, currently RIAA-inverse, 50µs pre- emphasis, CCIR468-inverse and CCITT O.41 psophometric inverse weighting for testing disc pre-amps, FM transmitter systems and noise weighting filters. All levels are generated digitally with high accuracy from look-up tables which are currently limited to third-octave frequencies.
Page 36 2. Manual Operation Fig. 2.25 Selecting a Weighting Curve Fig. 2.26 Weighting Curve Editor The weighting curve will be plotted and if it has not been defined it will be a flat line. It can be edited by moving the cursor and entering the level for each third octave frequency. The editing keys are: Editor keys Inverse response Inverting a weighting curve Normalise a weighting curve &...
Page 37: Sequence Testing
Sequence testing, as its name implies, involves the sending of a sequence of test signals for the complete and automatic evaluation of a system. Sequence testing on the LA100 is completely self contained and requires no programming effort, yet it is powerful and flexible, and designed to fully test any circuit or equipment which operates in the audio band in about one minute.
Page 38: Default Sequences
Loudspeaker frequency response and distortion "SPEAKER/GENERAL" TUD "20-20kHz FAST SWEEP" TX< LA100 Self Test − see section 10.6 of manual "LINDOS SELF TEST" /0%10,0 "XLR SOCKETS ONLY/0dB"TUCDN±6 "FM TEST""ONE CHAN MTD FOR THD"VRA:19,0GNY FM transmitter test. Dist. measured on mono tone German line-up levels "GERMAN SEQ"...
Page 39 "BTM/SEL SC"/-17%600,2"600OHM MATCHED"TrCEnz "TV SOUND/BC"/0TOCENZ "GTE SC"/-14%600,2"600OHM MATCHED"TrCEnz "GTE SUB/BB"/-19%150,2"150OHM MATCHED"TOCENz "20-20kHz FAST SWEEP"TX< As sequence 16 "LINDOS SELF TEST" "TEST+PATCH SC"%600,2"600OHM MATCHED"TrCENz "NSTD CHANNEL"/-10%600,2"600OHM MATCHED"TrCEnz As sequence 19 "PPM TEST" As sequence 15 "5S SWEEP (REPEAT)"TU< in LA100 V6.7 Software...
Page 40: Test Segments
10, 20, 30, 40, 50, 63, 100, 125, 250, 500, 1k, 2k, 4k, 6.3k, 8k, 10k, 12.5k, 14k, 15k, 16k, 18k, 20k, 25k, 30kHz. Sweep 300Hz-18kHz. Listed frequencies: 315,400,500,630,800,1k,1.25k,1.6k,2k,2.5k,3.15k,4k,5k,6.3k,8kHz. Phase 40, 100, 315, 1k, 6.3k, 10k, 15kHz (Mean) 3.5s Table 3.2 Test Segments available in LA100 V6.5 Software...
Page 41: Running A Sequence
3. Sequence Testing 3.1 Running a Sequence Running a sequence 22Hz-22kHz bandwidth Over 100 ready-made test sequences are currently available on the LA101, as listed in table 3.1, all constructed from the test segments listed in table 3.2 (and the control segments listed in table 4.1).
Page 42: Page Results Mode
3. Sequence Testing To abort a sequence when it is running press and hold on the LA101 until SEQ? appears (this may take a few seconds). To re-run the last sequence, press 3.2 Page Results Mode Sequence results Displaying sequence results Once in page mode, the results of a previously run test sequence can be viewed a screenful at a time by pressing to cycle forward through the results in the...
Page 43: Frequency Response Results
3. Sequence Testing Fig. 3.9 Crosstalk Results Fig. 3.10 Distortion Results 3.3 Frequency Response Results Graph display Moving the cursor Relative level The frequency response page shows a graph (fig. 3.6), usually covering 20Hz to 20kHz, with a scale marked at 1dB (single pixel) and 5dB intervals (double pixels). The cursor may be moved to any (third octave) frequency using the arrow keys , and the frequency and level (at the cursor position) may be read from the numerical readout...
Page 44 3. Sequence Testing Fig. 3.11 A Typical Printout from the LA102...
Page 45: Storing Results In Memory
3. Sequence Testing to 1, 2 or 3 (the number determines the number of copies). This makes the LA102 print the results whenever it receives a sequence and is useful where the LA102 is being used at a remote site to test a line or link, or even where a series of routine tests are being performed and printouts of each are required.
Page 46: Cyclic Identification Character
3.6 Cyclic Identification Character A cyclic identification character (A-Z) is transmitted by the LA101 with the serial number (as FSK) and printed out with the sequence results, as shown: LINDOS AUDIO SEQUENCE TEST SOURCE 6548A LINDOS AUDIO SEQUENCE TEST SOURCE 6548B This letter advances through the alphabet each time a sequence is run (returning to A after Z), and helps in sorting out a day’s tests.
Page 47: Input Level
4). By default, Bank 0 contains the Lindos default sequences, and after option 4 is chosen from the reset menu any user defined sequences in Bank 0 will be replaced by the Lindos default sequences. Bank 1 also contains the Lindos default sequences, but this bank cannot be edited.
Page 48 The 10 Lindos default sequences vary mainly in the levels at which each test is carried out relative to test level, and the levels used are the result of careful analysis of various codes of practice and specifications issued by the BBC, IBA, ITC, British Telecom, IEC, EBU and CCITT.
Page 49 (after pressing the key). Sequence 16 is a Selftest sequence which can be used to test the LA100 using XLR leads to connect the two units back to back. This sequence automatically selects the Selftest tolerance in the LA102, so a PASSED or FAILED display will appear as soon as it has finished.
Page 50: Interpreting Sequence Results
3. Sequence Testing into the LA101. This is essential if some of the less common test segments are to be used as they are not all provided in the default sequences. In particular, the slow, 20s, frequency sweep (segment S), the MOL test (segment H) and the user level segment (K) are extremely useful.
Page 51 3. Sequence Testing When running a sequence the FSK data and test tones are generated on both output channels and the LA101 instructs the LA102 which channel to use via data embedded in the FSK header. When testing stereo equipment, both channels are normally connected through the device under test, as shown in fig.
Page 52: Single Register Operation
3. Sequence Testing testing two independent mono communication channels. Set LA102 configuration Y1 to automatically store sequence results and press . A sequence can now be sent to the LA102 L channel input by running a sequence with the L channel selected on the LA101 (press on the LA101 when in sequence mode to set the LA102 measurement channel).
Page 53: Fsk Failure − Error Codes
3. Sequence Testing register 1 (perhaps from a reference tape, or from a device which is known to be good). 3.13 FSK Failure − Error Codes FSK failure Sequence error Sequence failure FSK speed tolerance The FSK system used is very effective in coping with speed errors on tape replay, because of the repeated resynchronising that it provides (the FSK itself will tolerate speed errors up to ±4%).
Page 54 3. Sequence Testing equaliser) more headroom may be required. An overload during frequency sweep measurement is detected and the message RANGE? is displayed in place of the level on both the screen and the printout where an overload has occurred (see fig. 3.21). Since the LA102 chooses its level based on the measured test level, a system which does not pass the 1kHz test level tone may cause a similar problem.
Page 55: Peak Programme Meter (Ppm) Testing
Note that this allows sweeps at low levels to be run and accurately plotted. An example for experienced users: (the following assumes sequence 6 contains the Lindos default sequence) Try sweeping the CCIR weighting filter in the LA102 (at -20dBu): LA102:...
Page 56: Normalisation Of Frequency Response
3. Sequence Testing Segment Frequency Duration Level Target Reading 5kHz 100ms +8dBu PPM6 5kHz 10ms +8dBu PPM5½ 5kHz +8dBu PPM5 5kHz 1.5ms +8dBu PPM3¾ 10kHz 0.5ms +8dBu PPM1¾ 1kHz +12dBu PPM7 1kHz +8dBu PPM6 1kHz +4dBu PPM5 1kHz 0dBu PPM4 1kHz -4dBu PPM3...
Page 57: Subtracting Reference Curves
The reference response should be measured either by using a normal Lindos test sequence containing a frequency sweep, or by using the test tape or frequency sweep mode (see chapter 6).
Page 58 3. Sequence Testing sequence, and the weighting name will appear at the top of the screen (in manual and sequence modes). As the LA101 can only apply weightings to third octave frequencies, some segments cannot be used. In particular, segments c, d, o are not allowed and will generate a CANNOT USE WEIGHTING...
Page 59: Automatic Results Storage
3. Sequence Testing This time the result will be a flat frequency response, as shown in fig. 3.24. By using a weighted frequency response with the inverse characteristic of the filter under test we have measured the deviation from the ideal response and the cursor can now be moved to any frequency to read the frequency response error.
Page 60: Printout Heading
It is sometimes convenient to include a date heading with results printouts and this is done automatically if the results are printed using the Lindos Support software (see appendix A.2). The LA102 can also print the date at the top of a test sheet (as shown in fig. 3.11), but it does not have a real-time clock so it is necessary for the user to ensure that the date is set correctly each day it is used.
Page 61: Running Single Segments
It would be possible to use the LA100 in manual mode to check the results, or it would be possible to run the entire test sequence again to see if any improvement is observed. A much quicker way though is simply to run the noise segment again, on its own, taking a few seconds.
Page 62: Using Filters For Sequence Measurements
3. Sequence Testing Single segments can be run on a single channel by pressing as described above and then selecting the channel by pressing Single segments only overwrite their own segment (or segments of the same type) in the LA102 leaving the rest, but running a whole sequence always clears the results memory completely, ready for the new results.
Page 63: Breaking Into A Repeating Sequence
It would be possible to implement a stereo O.33 sequence on the LA100 by reading both channels in turn during each tone, but it makes more sense to minimise switching transients by changing channels only once and...
Page 64 For these reasons, and because of its greater flexibility, the Lindos system is felt to offer better performance at lower cost, and the O.33 sequence will not be included as standard, though compliance with the CCITT and EBU measurement standards will be maintained as far as possible.
Page 65: User Defined Sequences
Lindos default sequences. Many users find that these make good starting points when designing their own sequences. The Lindos sequence system is very flexible and easy to use. Each test segment is allocated a letter, and a sequence is built by simply specifying the segment letters, together with an (optional) number which specifies the level that the segment will run at.
Page 66: The Sequence Definition
4. User Defined Sequences be used to test for compression effects on tape, for example). Some users define sequences to test different pieces of equipment, and make each sequence select a different tolerance within the LA102. For example, sequence 1 might be set up to test a Studer tape machine and select the Studer tape tolerance, while sequence 2 might test a Sonifex cartridge machine and select a suitable user tolerance.
Page 67: Control Segments
4. User Defined Sequences directly into the LA100 without a computer as the small, low resolution characters can be confusing to new users, but they are soon learnt, and the segment description provided by the LA101 can always be used as a confirmation.
Page 68: The La101 Sequence Editor
Note for computer users: Because of the limited character set of the LA100, it is best to use only the characters shown in section 4.2 within comments. Capital letters are preferred.
Page 69: Source Identification
A summary of all the editor keys can be found in the LA100 quick reference card. For example: To add wow & flutter measurement on to sequence 1 (assuming it currently...
Page 70 4. User Defined Sequences Fig. 4.4 LA102 Source ID Display Fig. 4.5 Editing the LA101 Source ID The LA101 has a source ID which by default will be the serial number and a cyclic identification character, A-Z (see section 3.6). This is normally sent automatically at the start of every sequence which contains a test segment, and can be edited by pressing from the sequence editor menu and using the normal sequence editor keys (fig.
Page 71: Copying A Sequence
4. User Defined Sequences 4.4 Copying a Sequence When a sequence is being edited, or viewed, it may be copied to a user sequence by pressing . The LA101 will ask which user sequence (1-10) you want to copy the sequence to. Press (for sequences 6-10).
Page 72: Test Level Segments (T,V)
4. User Defined Sequences Sequence 18 makes use of this facility to define a sequence compatible with German standards which specify distortion measured at +6dBu, sweep 20dB below +6dBu, noise referred to +6dBu, crosstalk at +6dBu, W&F at 0dBu and phase at 10dB below +6dBu. The definition is: T+6 U-14 C+6 D+6 N W Z-4 It could have been be defined as:...
Page 73: Frequency Sweep Segments (Opqrsuxorux)
4. User Defined Sequences determine the nominal level (used for frequency sweeps) and is also used to normalise crosstalk and noise measurements. If run as a single segment the tone is held after the segment has finished. 4.7 Frequency Sweep Segments (OPQRSUXorux) Segments O,P,Q,R,S Various frequency sweep segments are available, providing a range of sweep speeds (1½s, 5s or 20s), different frequency ranges (20Hz-20kHz, 10Hz-30kHz, 300Hz-18kHz...
Page 74: Crosstalk Segments (A,B,C,J,C)
4. User Defined Sequences 4.9 Crosstalk Segments (A,B,C,J,c) Crosstalk segments A, C and J measure crosstalk at six frequencies (40, 100, 315, 1kHz, 6.3kHz and 10kHz) taking 1s per frequency. The result is always calculated relative to the ‘TL OUT’ level as for noise measurements. Segment C operates at 0dB, while segment J operates at -10dB (as specified by the IBA for tape testing).
Page 75: Wow & Flutter Segment (W)
4. User Defined Sequences six frequencies (40Hz, 100Hz, 315Hz, 1kHz, 6.3kHz and 10kHz) but it takes 18s. As usual, all measurements are THD (plus noise). Segment G is similar to segment F but it has 50µs de-emphasis to avoid overloading FM transmitter systems. Tape azimuth 4.11 Wow &...
Page 76: Maximum Output Level (Mol) Segments (H, H)
4. User Defined Sequences possible to make the target levels appear on the printout by programming them into a tolerance definition, and this is explained in section 5.5. Typical results for the above example might look like this: USER LEVELS (+10dB) +9.3 +9.5 -0.2...
Page 77: Difference Frequency Distortion (D)
4. User Defined Sequences +3dBu. Maximum output level To calculate the MOL in nWb/m it is necessary to establish a relationship between the machine output and a known tape flux level. For example, if a 320nWb/m test tape gives an output of -2dBu, and the LA102 indicates an MOL of +7.5dBu, then the MOL of the tape is: 7.5 - (-2) 320 x antilog...
Page 78: Tone Burst/Tones Segment (!)
4. User Defined Sequences the double tone is -3dB, and the reference frequency to which the distortion is referred is 0dB. Intermodulation distortion 4.16 Tone Burst/Tones Segment (!) FSK decoders ASK decoders Testing FSK decoders The tone burst segment (‘!’) is a very powerful facility for generating tones and tone bursts.
Page 79 ‘!’ character. Note that segments D, E, F, G, I, K, T, V, W, Y and Z can all be defined in this way using the ‘!’ segment and this allows different levels or frequencies to be used, but remember that the LA102 will assume it has a standard Lindos segment so you will need to interpret the results intelligently.
Page 80 This could be used to test FSK decoders operating at other baud rates, but would not normally be used to generate FSK within a Lindos sequence. 6. To simulate the W&F test segment with a -3.8% speed error. FSK ‘W’ followed by 3005Hz for 12.5s.
Page 81: Repeating Segments And Sequences (<)
4. User Defined Sequences This segment will produce a stepped graph but the levels will be correct at the listed frequencies on the printout. Note that the levels could be specified for the tones providing weighted sweeps. A simpler segment, using less frequencies is more manageable but remember that the printed levels will only be correct at the specified frequencies (30, 100, 500, 1k, 6.3k, 10k, 15k, 20kHz): !U30,1268.7,,100,1040.6,,500,112.5,,1000,1532.8,,6300,281.2,,...
Page 82 4. User Defined Sequences The LA102 results memories are split into compartments where each compartment can hold one segment from each segment group listed below. Configuration C (in the LA102) must be set to determine the number of compartments per memory, and the number of memories.
Page 83: Selecting A Tolerance (±)
The PASSED FAILED Lindos Self Test sequence (sequence 16) makes use of this feature to select tolerance 16 (the Selftest tolerance) in the LA102: "LINDOS SELF TEST" T U C D N ±16 Note that the tolerance is only selected temporarily.
Page 84: Sequence Level Segment (/)
Generating the tone on both channels simultaneously (as Lindos sequences normally operate) results in a zero amplitude difference signal giving less valid results.
Page 85: Subroutine Segment (>)
4. User Defined Sequences The channel selection segment (:) can be used to allow for this special case. If 16 is added to the physical channel number, before a distortion segment, then that distortion segment will only put the tone on the channel which is being measured and will MUTE the other channel.
Page 86: Subtract A Reference Curve (\N)
4. User Defined Sequences The headroom segment, n, indicates to the LA102 that a 0dB sweep may peak at anything up to ndB. This segment is normally placed immediately before the frequency sweep segment, and must be positioned after the test level segment (T or V). For example, if testing a filter which has 0dB gain at 1kHz and +12dB gain at 10kHz, the following sequence could be used: T ^+12 U...
Page 87: Ccitt O.33 Sequences
(00-99). The LA101 will generate an FSK header complying with the CCITT O.33 specification: 110 baud, 1 start bit, 7 data bits, 1 even parity bit and 2 stop bits (as for Lindos FSK), with the following characters:...
Page 88: Apply Weighting (=N)
4. User Defined Sequences 4.29 Apply weighting (=n) To automatically apply an LA101 weighting to a sequence definition, use the =n control segment, where n is the weighting number. 1-5 are user weightings; 6 is RIAA inverse; 7 is CCIR 468-3 inverse; 8 is CCITT O.41 inverse and 9 is 50uS de-emphasis. Ensure the weighting is defined before running the sequence.
Page 89: Tolerance Testing
(section 5.5) The LA102 allows up to ten user tolerances to be stored in non-volatile memory using the built-in tolerance editor (section 5.6) or by using Lin4win, the Lindos Support Software for Windows® on a remote computer (section 5.7).
Page 90: Pre-Defined Tolerances In The La102
PQRSUX +-2,+-1,,,,,,,,,,,,,,,,,,+-2 -50,-59,? 1-10 User Tolerances -63,? ?,-40,? ?,,,-40,? 11 IBA Tape/General ?,,,-65,? ?,-65,? PQRSUX +6,+2-2.5<3,,,,+-1<1.5,,,,,,,,,+2-2.5<3,,,? 0.04,,?,+-0.2 -17,-25,-36,,,-32 -25,-36,,-32 16 Lindos LA100 Self Test -34,,-40 -41,-45,-41 +0-.15,,+-.1,,+-.05,,,,,,,,,,+-.10 +-60,+-35,+-15,+-30,+-46,+-60 +-.05 .12,,+-15,+-.3 -107,-105 -95,-98,-95 12 IBA Tape/Restricted Use -90,,,-80 +-1.5 -80,-86,-76 PQRSUX +6,+3.5-2.5<3,,,,,+-1.5<2,,,,,,,,+3.5- 2.5<3,,,?
Page 91 5. Tolerance Testing sequence printout HP Deskjet printout Printout from HP Deskjet Sequence results Fig. 5.4 A Typical Sequence Printout with Tolerance Testing (HP Deskjet)
Page 92: Applying A Tolerance
Pre-defined tolerances Tolerance definitions Tolerances 11-20 are pre-defined in the LA102 and cannot be changed. Tolerance 16 is the Lindos Selftest tolerance which is normally automatically selected by sequence 16, the Selftest sequence. The LA101 XLR outputs should be connected directly to the LA102 XLR inputs using good, screened cable.
Page 93: Tolerance Strings
IBA Code of Practice is still considered by many to be the definitive standard for broadcast users and it is still in widespread use. Tolerance 14 is a Lindos specification for a domestic cassette machines. Any good cassette machine should pass.
Page 94 5. Tolerance Testing The segments may be specified in any order, and any segments that have the same tolerance specification (eg R and S, or T and V) can be specified together by putting the segment letters together. If any tolerance for a particular value in a segment is omitted the tolerance for the previous value is assumed.
Page 95: Printout Format
5. Tolerance Testing because the spot frequency levels that the tolerance is applied to are affected by the normalisation (ie the levels that are checked against the tolerance are always the same as the levels that are printed). A tolerance which has been defined assuming 1kHz normalisation might fail every value if given absolute levels instead of normalised levels.
Page 96: The La102 Tolerance Editor
5. Tolerance Testing character is used to print a value without tolerance testing, and also that an empty field, after a field will also cause the corresponding results line to be suppressed (since empty tolerance fields always default to the last field which had an entry). It is not possible to apply a tolerance to suppressed results values (because the printout would be very misleading if an invisible value failed).
Page 97 5. Tolerance Testing keys move the cursor right and left by one character, while move it 21 characters (a screen width), with the display scrolling sideways as necessary. Editor keys keys are used to change the character at the cursor, and they cycle through the available characters: <space>...
Page 98: Editing Tolerances On A Remote Computer
Tolerances can be saved to disk for later use, and transferred from the computer to the LA102. If more than 10 tolerances are frequently used the Lindos Support Software should be used to store the tolerances on disk and transfer them to the LA102 as necessary. The Support Software also makes it easier to edit Tolerance definitions using a full-size keyboard so the LA102 tolerance editor can be ignored.
Page 99 5. Tolerance Testing Fig. 5.7 Tolerance editor Fig. 5.8 Tolerance 17 Fig. 5.9 Viewing the Tolerance Fig. 5.10 Copying Mode Fig. 5.11 The Opening Edit Screen Fig. 5.12 The Final Version Fig. 5.13 Setting Configuration T...
Page 100 5. Tolerance Testing...
Page 101: Using Test Tapes And Discs
6.0 Using Test Tapes and Discs Cassette machines Replay frequency response The LA102 can automatically take measurements, without any special programming, from standard test tapes and discs (Compact Discs or gramophone discs) which do not contain FSK. A frequency response graph can be displayed on the screen, printed, tested against a tolerance or read into a computer just like a frequency sweep from the LA101.
Page 102 6. Using Test Tapes and Discs The LA102 will interpolate the frequency response samples that it recorded to produce the frequency response graph (fig. 6.3) so it is possible to move the frequency cursor (using the keys) to any third octave between 20Hz and 20kHz to find the response at that frequency (see section 3.3).
Page 103: Frequency Sweep Mode
6. Using Test Tapes and Discs 6.2 Frequency Sweep Mode Press to enter frequency sweep mode (fig. 6.4). The LA102 will display SEQ 3 FREQ SWEEP and range and channel indicators. The frequency sweep should now be played from the test tape, CD, gramophone disc or other source. Press to exit from this mode when the sweep has finished and the LA102 will display the frequency response graph.
Page 104: Frequency Response Results
They can be stored in a results memory using printed using , read into a remote computer using the Lindos Support Software (see appendix A.2) or tolerance checked by defining a tolerance for segment U (see chapter 5).
Page 105 6. Using Test Tapes and Discs be displayed (by pressing ), printed, tolerance tested, or read into a computer in the usual way. This facility must be used with care, as some test tapes contain a 3150Hz tone at a different level to the frequency response section.
Page 106 6. Using Test Tapes and Discs...
Page 107: Applications Advice
Azimuth check Testing a tape machine Tape azimuth The LA100 is ideally suited for testing and aligning tape machines. Test tapes may be used to measure speed and wow & flutter with the LA102 although it is quite feasible to make record-replay measurements for the latter (see section 2.14).
Page 108: Loudspeakers
7. Applications Advice 7.2 Loudspeakers The LA100 can be used to measure level, frequency response, distortion and phase on a loudspeaker. Ideally an anechoic chamber should be used to reduce the effects that room reflections have on frequency response. Loudspeaker measurements have proved very successful, using a microphone and pre-amp and relying on the FSK passing through the system although careful microphone positioning may be required (see section 3.13).
Page 109: Lines, Links & Networks
Broadcast users Line testing Network testing Lines/links Testing a line or link The LA100 is ideally suited for testing lines, links and networks. An automatic test sequence can be generated by the LA101 and received by the LA102 at the other end of the line.
Page 110: Mixing Consoles
Testing a system with a large number of channels can be time-consuming despite the fast automatic test sequences. The LA100 can test two channels with a single sequence and can also hold up to 6 sets of sequence results in its non-volatile memory. This means that results for up to 12 channels can be held in memory for later printing (see section 3.5).
Page 111: Compact Disc Players
(including pass/fail tolerance testing) provided by the LA100 and it is often a simple matter to send a few commands to do the test and read the results back for logging on disk. A full description of all of the remote commands is given in chapter 9.
Page 112: Fm Transmitter Systems
7. Applications Advice 7.11 FM Transmitter Systems Pre-emphasis De-emphasis European FM transmitter systems use a 50µs pre-emphasis filter (-3dB at 3183Hz) to amplify the high frequencies before modulation, and the FM receiver has a corresponding 50µs de-emphasis filter to restore a flat frequency response. This is to obtain the best noise performance from the system (since FM systems have correspondingly higher noise at higher frequencies) and is possible since programme material generally has a lower level of high frequency components.
Page 113: Using Printers
1 stop bit. This is normally achieved by setting DIP switches on the printer, or on the serial interface board, using a small screwdriver or pencil although the cover may have to be removed on some printers. If obtained from Lindos the printer will already have been set up correctly and tested.
Page 114: Printing
8. Using Printers Other switches may be provided for handshake mode in which case DTR/CTS handshaking should be selected (this is usually the default, but some printers also have XON/XOFF handshaking which the LA102 cannot use). Other DIP switches might control draft/NLQ mode, character set (country), automatic line feed (LF) on (CR), condensed typeface etc, but these settings are not too important and may be set however is convenient.
Page 115: Printout Format
8. Using Printers Auto Print Seq A0 Off, A1 On, A2 2 Copies, A3 3 Copies, A4 4 Copies Printer baud rate B1 75, B2 150, B3 300, B4 1200, B5 2400, B6 4800, B7 9600, B8 110, B9 19200 D Distortion display D1 %, D2 dB Graph width...
Page 116 8. Using Printers the appropriate configuration letter and use to change the setting. The baud rates and printer types and other printer related configurations currently implemented are shown in Table 8.1. All configuration settings are retained in non-volatile RAM and many only need to be set once.
Page 117: Choosing A Printer
Some printers have print ‘buffers’ or ‘spoolers’ which can hold a large amount of data freeing the LA102 before printing has finished. A typical Lindos printout to an Epson printer contains about 14Kbytes of data which can be held entirely in a 16K printer buffer (freeing the unit in 10 or 20 seconds).
Page 118: Epson Lq And Other 24 Pin Printers
LA102. Epson LQ printers have a serial interface built in, but they use a 5 pin DIN connector so they need a Lindos SL7 printer lead instead of the more usual SL2. See appendix C.3. Set LA102 configuration P6. For simplicity in the LA102 only the 8 pin graphics modes are used and this results in taller graphs than Epson FX and other 9 pin printers.
Page 119: Portable Printers
8. Using Printers codes implemented. Most Laserjet II compatible printers will not print the double width graphs which the LA102 sends in two halves (unfortunately this is necessary because the LA102 does not have enough free internal RAM to hold a full strip of the graph). Most other types of inkjet printer (Canon, Epson, etc) can be configured to emulate either HP Deskjet or Epson.
Page 120 This will never happen with Lindos SL2 printer leads, as the data input line is not connected, but some users who make their own leads sometimes connect this line (unnecessarily) to the printer’s data output line.
Page 121: Remote Control
Remote control can also be useful in a studio or lab (perhaps where the LA100 is rack mounted and not easily accessible) as the computer provides a large high-resolution screen and full size keyboard.
Page 122: Connecting The La100 To A Computer
Most computers have a suitable RS232 (or RS423) compatible serial port and connection is extremely simple using the relevant Lindos leads (see appendix C for order codes and wiring details). Only one serial port is needed in the computer, even when connecting both the LA101 and the LA102, although a second serial port may be useful for connecting a mouse, serial printer or other serial device.
Page 123: The Rs232 Serial Data Format
The remote computer should be configured to use the same serial data format as the LA100: 1 start bit, 8 data bits, no parity and 1 (or more) stop bits. The CTS and DTR lines are used for hardware handshaking - see Appendix C for wiring diagram. XON/ XOFF or software handshaking is not supported.
Page 124 It is also a good idea to send a Carriage Return (CR) character after changing the baud rate, to flush the LA100 line input buffer and ensure that it is ready for a command. This is not strictly necessary, but it will make the system recover if it was left in a peculiar state (perhaps by unplugging or resetting the computer during a previous communication).
Page 125: Command Format
A few very old computers can only operate at a single baud rate and cannot generate break signals. In such cases it is still possible to use them with the LA100 by setting the LA100 configuration R baud rate (see section 1.6) to match that on the computer. The...
Page 126: Some Examples
LA101 to return to keyboard mode leaving the LA102 in remote mode. 9. 5 Some Examples Before writing any software to control the LA100 it is a good idea to become familiar with some remote commands by using either the ‘Remote Commander’ provided with the Lindos Support software or a suitable terminal emulator program.
Page 127: Hints On Writing Programs
2 and 3. It is recommended that all programs assume the LA100 to be set to 300 baud and enter remote mode as described in section 9.3, selecting a higher baud rate once communication is established.
Page 128: Remote Command Summary
9. Remote Control General Purpose Commands (section 9.8) Reset (frequency, level, channel, measurement etc) Total reset and return to manual mode (equivalent to tapping Return to manual mode (keyboard control) Display test. Display goes all black and then all white on next char. Identify.
Page 129 9. Remote Control Read the level range Enable autoranging Set input impedance M?p,n Rapid level measurement: n samples with sampling period p ms. Running a Sequence (section 9.14) SQn,m,c,r Run and receive test sequence n, segment m, channel c, register r SPn,m Set sequence parameters.
Page 130: Errors
9. Remote Control then another procedure will be needed to read a binary byte from the LA100, and it is important to ensure that all bytes can be read (some communications libraries particularly on Unix or MSDOS systems may interpret ASCII 4 or ASCII 26 as an end-of-file character and terminate, so it is important that a raw-binary mode is used for this, where relevant).
Page 131: General Purpose Commands
9. Remote Control 9.8 General Purpose Commands These commands control various LA100 settings, but are not related to audio measurement in any way. Most commands are common to both units, but remember that commands can be prefixed with a ‘1’ or a ‘2’ to make them only affect the LA101 or LA102 respectively.
Page 132 LA102 displays input baud rate to left of output baud rate if different. Note that the computer’s output baud rate must be set to match the LA100 input baud rate after this command (and vice versa). If m is omitted then the input and output baud rates are both set to a value determined by n.
Page 133: La101 Output Commands
9. Remote Control Read Last Error Number: E? E? read error number The last error number is returned by the LA102 (terminated with a CR character), and any displayed error message is cleared (on both the LA101 and the LA102). See section 9.8 for further details and appendix E for a full list of error messages and numbers.
Page 134 9. Remote Control affect the output level until the next 1LV command. The test level is also used by sequences, so it is often useful before an SQ command. Most programs will not use this facility as it is often simpler to calculate the absolute output level and set it directly using the 1LV command.
Page 135: La101 Preset Commands
Some obsolete commands are also available for backwards compatibility with very early , A:n, L:n, R:n, WTn, D0, D+, D- set input channel, attenuation, left LA100 units: channel, right channel, weighting, DC0, DC+ and DC- respectively, but they have now been superseded by the IC, LV, OC, WC and WF commands.
Page 136: La101 Frequency Sweeps & Tone Burst Commands
9. Remote Control frequency and ensure that it is displayed rounded, precede the frequency with a minus sign (‘-’). Omitting any value leaves the previous value set. Example: 1FP-100,-315,-1000,-6300,-10000. Level Presets: 1LPv1,v2,v3,v4,v5 LP set level presets Set level presets 1 to 5 to the specified levels, v1 to v5.. Omitting any value leaves the previous value set.
Page 137: La101 Weighting Curves
9. Remote Control Examples: TB1000,20 will generate 20 cycles of 1001.6Hz; TB10000,0.1 will generate 1 cycle of 10080Hz. 9.12 LA101 Weighting Curves User weighting curves Defining weighting curves on a computer The LA101 has 4 pre-defined and 5 user definable weighting curves which can be used to adjust the output level depending on the output frequency.
Page 138 9. Remote Control mode (see chapter 2), but note that it is often possible to increase the accuracy by instructing the LA102 to perform several measurements over a short period of time and return an average value. Unlike manual mode, the LA102 will not take any measurements, or perform any autoranging while it is waiting for a command, but only when a relevant measurement command is received.
Page 139 9. Remote Control may be set directly using the RN command, or if unsure of the level, use L? to read the level with autoranging enabled. See section 2.8 for further details. Read Level: 2L?n L? read level command AR autorange The level is returned in dB as a decimal number with 2 decimal places, terminated with a CR character.
Page 140 This will give an indication of the source of the flutter. Set Gain Code: 2G!n Set internal gain code n (0-19) for Lindos use only during calibration. This is similar to the RN command, but allows independent specification of front-end gain and main gain.
Page 141: Running A Sequence
(1SQ19,,1 to run sequence 9 on the L channel without making the LA102 wait for a sequence). Similarly, repeating sequences will never finish (until a key is pressed on the LA100) so they are best avoided. It makes more sense to run a sequence, read the results...
Page 142 E? or R? command without waiting for the sequence to finish (since it will be held up by the handshake line). However, sequences which are run from the LA100 front panel (using the key) can be interrupted by sending a command (since the handshake line will not indicate that the unit is busy).
Page 143: Defining A Sequence
9. Remote Control sequence before sending any commands if the results are wanted. 2. Although the parameters sent to each unit are identical, the LA102 ignores the sequence number and the LA101 ignores the register number, since they are both irrelevant.
Page 144: Reading Sequence Results
9. Remote Control Note that the ± character used for specifying a tolerance number within a sequence (see section 4.19) is not a standard ASCII character, so the | character (ASCII 124) should be used instead, as in the last example above. Extremely long sequences should be split into two or more sequences and linked with the sub-sequence segment >...
Page 145 9. Remote Control Bit Value Action If this bit is set then page breaks and margins are suppressed making the text suitable for processing and storage on disk. If this bit is clear the text is formatted as though it was being sent to a printer, leading spaces are included at the start of every line and the text is divided into formatted pages using configuration N to determine the page length and configuration M for the top margin.
Page 146 9. Remote Control LINDOS AUDIO SEQUENCE TEST LINDOS AUDIO SEQUENCE TEST SOURCE 0518E LA102 0518 V6.0 SOURCE 0518E LA102 0518 V6.0 SEGMENTS +TDZ SEGMENTS +TDZ TEST LEVEL OUT [T] 0dB TEST LEVEL OUT [T] 0dB +0.01 -6.65dBu , +0.01 , -6.65dBu...
Page 147 9. Remote Control A 3 line header is returned first giving the start frequency f , the finish frequency f the number of samples n with each value in ASCII decimal being terminated with a CR character (in current software n is always 256, but this should not be assumed). This is followed by n samples of binary data, with each sample taking 2 bytes.
Page 148 This is followed by 2 bytes per sample for every sample (this is always 256 in current software). This binary data should be held in a buffer, as it is, without processing. 9. Send a KB1 command to return the LA100 to manual mode. Read Segment List:...
Page 149 9. Remote Control R?1,W Read W&F weighted, W&F unweighted, speed and phase R?1,+ Read source ID text (up to 21 characters sent via FSK) To avoid any risk of the remote computer mis-interpreting the results, the format is always fixed: distortion results are always returned in dB relative to the level of the fundamental (never in percent, regardless of the configuration setting) and Test Level results are always in absolute dBu.
Page 150: La102 Heading And Date
Tolerances can be transferred to and from the LA102, and this facility is used by the Lindos Support Software to allow remote editing of tolerances on a computer. It is also possible to run a sequence and test the results against a tolerance without actually reading or processing the results themselves.
Page 151: Memory Operations
MX command to swap the memories back to their original state. This technique is used by the Lindos Support Software to read results from other memories without losing the current results in memory 0.
Page 152: Using The Smart Sequence Modes
However, since it is recommended that all programs always check the segment list to find which results are available this is largely irrelevant. The LA100 itself, and the Lindos Support software behave correctly, and will not access results for a segment which is not in the segment list.
Page 153: User Sweeps
9. Remote Control Smart Sequence Mode: SM smart sequence mode The SM command selects a smart sequence mode (n=2 for test tape mode or 3 for frequency sweep mode) and puts the LA102 back under keyboard control. Note that the LA102 cannot decide when it has received all of the tones or sweeps and the remote computer should determine this (by reading the tape counter, by asking the user or by waiting the correct length of time, for example).
Page 154 The Lindos sweep segments actually remain on the last frequency of the sweep for extra time, with the slight advantage that sample 256 (delayed) remains correct over a range of speed errors.
Page 155: Using Sequences
9. Remote Control 9.22 Using Sequences Using sequences from remote mode is very simple and the basic steps are outlined below. Start by sending an MC to clear the results memory. It can be a good idea to download the sequence to the LA101 before running it to be sure of what you are running, and it is best downloaded as sequence 0 using a 1DS0,xxx...
Page 156 9. Remote Control...
Page 157: Service Information
10.0 Service Information Resistor networks Service information The information given here is intended to assist users in identifying simple faults, replacing printed circuit boards (PCBs), and fitting exchange EPROMs when software updates are supplied, but users are advised not to undertake detailed fault finding. Circuit diagrams showing the power supply, microprocessor, interfaces and input and output stages are shown in appendix D, but full circuit diagrams are not supplied at present - justified by the fact that it is very difficult to fault find efficiently without a full...
Page 158: Recalibration
SELFTEST TOLERANCE 6 PASSED. section 10.6 if it fails. It is also possible to check the calibration of the LA100 using an accurate AC milli- voltmeter which is traceable to a national or international voltage standard, and many calibration laboratories will perform such a test for a moderate fee although they will not be able to recalibrate the unit if it fails.
Page 159: Power Supply Voltage
Power supply Mains voltage Voltage selection (120/240V) Board modification The LA100 is normally factory set for 220-240V, or 110-120V if requested, and the voltage is marked on the rear panel. It can be changed by removing the bottom cover and disconnecting and removing the bottom PCB.
Page 160: Fault Diagnosis
(section 10.9), or possibly a microprocessor fault (section 10.13). 3. Display shows EPROM FAILED: The software EPROM has failed and should be replaced with a new one from Lindos (in such cases the unit may still be usable − press key to attempt to continue).
Page 161: Selftest Failed
10. Service Information 10.6 Selftest Failed Selftest failed Distortion poor Noise poor Because of the low residual levels and the very stringent tolerance specification it is important that good quality screened leads are used (with the screen connected to the LA102 XLR ground, pin 1) and that the 10k input impedance is selected for this test.
Page 162: Power Supply Check
10.9 Battery Testing This section refers to lithium-ion batteries as used in the LA100 MK3, if you have an earlier unit with NiCAD batteries please refer to section 10.9 of the fifth edition manaul, which is available from the downloads section of our website www.lindos.co.uk.
Page 163 10. Service Information Fig. 10.2 Measuring V Fig. 10.3 Measuring V Battery current can be checked by plugging the battery connector on to the positive pin only and connecting a meter in series with the negative pin (fig. 10.4). Use a 10A range to minimise the voltage drop −...
Page 164: No La101 Output
10. Service Information this for you: hold and tap and leave on for several hours. When the unit has turned off, hold the keys and connect the mains and the LAST TIME display will indicate how long the battery lasted before the unit switched off. To test an LA102 battery, either put it into the LA101, or use the LA101 EPROM in the LA102.
Page 165: Reed Relay Faults
10. Service Information source such as a test CD can be used with the LA102, while the LA101 output can be checked on an oscilloscope or DVM. Some common level errors have obvious causes: a small error of 0.2dB or less can be caused by fitting an EPROM with the wrong serial number and hence the wrong calibration data (ensure that the serial number on the EPROM matches that on the chassis above the keyboard).
Page 166: Microprocessor Faults
10. Service Information a +20dBu tone on both channels. If the fault is only present with a particular input impedance setting then RL3, the impedance switching relay is probably the cause. If the fault is independent of input impedance then the fault is probably RL1 (left channel faulty) or RL2 (right channel faulty).
Page 167: Display Faults
CAUTION − BOARDS AND CHIPS CAN BE DAMAGED BY STATIC. 10.16 Spares A Lindos Spares Price List is available upon request. Individually itemised parts lists are not issued as in many cases small parts are sent free of charge on telephone advice to avoid invoicing.
Page 168: La101 Loudspeaker
V. Plug a DAC0832 into IC6 and an LM386 into IC7, fit a 64 (0.3W) loudspeaker at LS1 and remove the protective tape from the loudspeaker grill on the top cover. A loudspeaker upgrade kit is available from Lindos.
Page 169: Appendix A Accessories
A.3 Conversion Kits (Rack Mount/Separate) Conversion kits Dummy unit The LA100 comprises the LA101 Audio Oscillator and the LA102 Audio Measuring set, which are normally supplied as two separate units, while the LA100R consists of the same two units bolted together with double width covers and end plates for 19" rack mounting (2U high).
Page 170 Appendix A Accessories Fig. A.2 The CV1 Rack Mount Conversion Kit 19" rack mounting...
Page 171: Appendix B Audio Sockets
Appendix B Audio Sockets Audio sockets Connectors Both the Oscillator and the Measuring Set have a pair of XLR sockets at the rear and a pair of Post Office, B-gauge (small tip) jack sockets at the front of the unit for two channel (usually Left and Right) audio testing.
Page 172: Front Jack Sockets
Appendix B. Audio Sockets B.2 Front Jack Sockets B-gauge jack sockets Connectors Front jack sockets PO jack sockets audio sockets The front sockets are PO316, B-gauge (small-tip) jack sockets, and a suitable plug (fig. B.2) is available from RS components (tel: +44 1536 201201; part number 477-618) The LA101 output impedance at the jack connector can be switched between 75 and 600 (but not 10 ), while the LA102 input impedance can be switched between...
Page 173: Appendix C Rs232 Connections
C.1 to C.3 (using the same colour system as in fig. C.1 for the LA100 end of the lead). LA101 to LA102 and LA102 to computer leads (for daisy-chaining) should be wired pin to pin.
Page 174 Appendix C RS232 Connections Ground (green) (orange) (blue) (green) (black) Ground (black) (blue) (red) Viewed looking into solder side of 25 pin D plug Viewed looking into solder side of 9 way D line socket Fig. C.1 LA102 Socket Fig. C.2 Printer Plug Ground (orange) (green)
Page 175: Appendix D Circuit Diagrams
Appendix D Circuit Diagrams D.1 LA100 Microprocessor Circuit diagrams Microprocessor...
Page 176 Appendix D Circuit Diagrams D.2 LA100 Power Supply & Interfaces Circuit diagrams Power supply DC-DC converter...
Page 177 Appendix D Circuit Diagrams D.3 LA102 Front End Circuit diagrams Front end circuit Reed relays Relays...
Page 178 Appendix D Circuit Diagrams D.4 LA101 Attenuator & Output Amplifier Circuit diagrams Output amplifier Attenuator Fuses...
Page 179: Appendix E Error Messages
3.19). CANNOT USE WEIGHTING EPROM FAIL (128) An EPROM failure has been detected. Contact Lindos for a replacement EPROM (and quote your serial and version number). Note that if you press the SEQ key it may be possible to continue using the unit if a bit has failed in an area of EPROM which provides features that you do not use.
Page 180 Appendix E Error Messages segments use levels above the test level. MEMORY CLEARED The RAM was in an inconsistent state (usually at power-up) and (129) was therefore cleared completely. May be due to a battery failure, or to new software having just been installed. Memory corruption MEMORY OPERATIONS No memories available, reduce configuration C - see section 4.18.
Page 181 Appendix E. Error Messages Level results are available. Since noise and crosstalk measure- ments are relative to the measured test level these segments must be preceded by a test level segment (eg the sequences RCIN or RCINT will generate this error. They should read TRCIN). TOO LONG (64) Remote command line too long (over 250 characters).
Page 182 Appendix E Error Messages...
Page 183: Appendix F Frequency Lists
Appendix F Frequency Lists F.1 IEC Third Octave Frequencies (and remote codes) Table F.1 shows the nominal third octave frequencies which are used by the LA101 in manual mode when the frequency is changed with the keys. These frequencies are also used for third octave frequency sweeps and the code refers to the third octave frequency code which is used from remote mode when running third octave sweeps with the command.
Page 184 Appendix F. Frequency Codes Code Freq Hz Code Freq Hz Code Freq Hz Code Freq Hz 4.7683 13.871 43.596 135.63 4.8440 14.194 44.389 139.50 4.9221 14.532 45.211 143.61 5.0028 14.886 46.064 147.96 5.0862 15.258 46.950 152.58 5.1724 15.650 47.870 155.00 5.2616 16.061 48.828...
Page 185 Appendix F. Frequency Codes Code Freq Hz Code Freq Hz Code Freq Hz Code Freq Hz 406.90 1302.0 3906.2 12019 415.55 1324.1 4006.4 12254 424.59 1346.9 4111.8 12499 434.02 1370.6 4222.9 12755 443.89 1395.0 4340.2 13020 454.21 1420.4 4464.2 13297 465.02 1446.7 4595.5...
Page 186: Appendix G La102 Filter Graphs
Appendix G LA102 Filter Graphs Tolerance 31.5 -29.9 ±2 -23.9 ±1.4 -19.8 ±1.0 -13.8 ±0.85 Response (dB) -7.8 ±0.7 -1.9 ±0.35 Weighted Response ±0.2 +5.6 ±0.5 Unweighted Response 3.15k +9.0 ±0.5 +10.5 ±0.5 +11.7 ±0.5 6.3k +12.2 7.1k +12.0 ±0.2 +11.4 ±0.4 +10.1...
Page 187 Appendix G. LA102 Filter Graphs IEC98 Rumble Curve A Tolerance ±1.5 -0.5 ±0.5 ±0.5 Response (dB) ±1 ±1 ±1 3.15k ±1 IEC98 Rumble Curve B Tolerance 31.5 ±1 ±1 ±1 ±1 ±1 ±1 ±1 Frequency (Hz) 3.15k ±1 Fig. G.3 IEC98 Rumble Weighting Curves (Noise options 4 & 5) IEC386 Wow &...
Page 188: Appendix H Fsk Header Format
Appendix H FSK Header Format FSK header format The LA100 FSK (Frequency Shift Keying) uses 110 baud with a mark frequency of 1650Hz and a space frequency of 1850Hz. The data is transmitted using 1 start bit, 7 data bits, 1 even parity bit and 2 stop bits, as shown below:...
Page 189: La100 History
A UPG1 upgrade is recommended and this involves returning the LA100 to Lindos. As part of the upgrade both the LA101 and the LA102 will be fully repaired, tested, refurbished and recalibrated. The processor and power-...
Page 190 PASS or FAIL result displayed on the LA102 LCD. A variety of standard (BT, IBA, Studer etc) and popular (Lindos cassette etc) tolerances are defined in EPROM, and up to 5 complete tolerances may be entered and stored in non-volatile memory. All tolerance information and whether the test passed or failed may be printed with the test results.
Page 191 (section 2.3). V4.10 Minor changes. V4.11 Test tape operation: As well as responding to recorded or transmitted Lindos sequence tests, the LA102 can measure, display, print and tolerance-check frequency response, W&F and speed errors using a standard test tape. Voice announcements are ignored and all levels and frequencies are logged and interpolated to produce a frequency response graph (chapter 6).
Page 192 New units supplied with V5.6 or later software will be fitted with these waveform EPROMs, but users upgrading older units who wish to use this feature should request new waveform EPROMs from Lindos. To find whether a unit has OSC13 EPROMs, press to step through the waveforms and look for (or remove the bottom cover and check the label on the EPROMs).
Page 193: Rack Mounted Unit (La100R)
Rack mount version rack mounting 19" rack mounting The LA100R is a 2U rack mount version of the LA100, comprising the LA101 and the LA102 bolted side by side to make up the 19" width. Conversion kits to convert to and from single units are also available (see section A.3).
Page 194: Power Supply Monitoring (La100P)
When the LA100 is being used to test critical transmission paths for live broadcast material it is often desirable to be able to detect failures within the LA100 itself. The power supply monitoring circuit provides a jack socket on the rear panel connected to an internal relay.
Page 195: Appendix J Specification
RIAA, CCIR 468, O41, 50µs de-emphasis. In addition, up to 5 user programmable weighting curves may be entered. Sequences 10 programmable sequences, with Lindos defaults. Segments 47 selectable test segments for user assembly. Frequency Shift Keyed data transmitted over signal path,...
Page 196: La102 Audio Measuring Set
Appendix J Specification Presets 5 frequency and 5 level presets. Relative levels Current level can be stored as a working level for testing microphone inputs etc. Tone bursts 100µs to 27 minutes, programmable frequency, level and duration (specified to a resolution of 100µs). Sequences of tones or tone bursts can be easily programmed, and can be made to repeat.
Page 197 Appendix J Specification Options 7-9 80Hz-400Hz, 1.8kHz-21kHz and 12-21kHz bandpass. Residual Noise -117dBu at 1kHz, -111dBu at 6.3kHz typical. Residual crosstalk Distortion THD+Noise, relative, with automatic fundamental measurement and filter frequency selection. Measured with a combined multi-stage notch and high-pass filter. Frequency tolerance is ±1% for a 70dB notch.
Page 198: Common To Both Units
Connectors PO Jacks (B gauge, small tip) & XLR-3s at rear. Guarantee 1 year. Fast repair/software recalibration service available. Technical support Lifetime technical support from Lindos via telephone +44 1394 380307 (usually 24 hours), fax +44 1394 385156 or mail.
Page 199: Index
Index ! character in tolerance 9 pin dot matrix printers ! tone segment 76, 78-80, 85 : segment (set channel) % conversion = sign % distortion tolerances > segment (call subroutine) % segment (set impedance) ? segment (pause) (‘SEQ ERROR 12’) + segment 62, 70 A weighted noise...
Page 200 Attenuator Baud rate codes Audio sockets 12, 171-172 BBC computer Auto Print Seq 13, 115 Betacam channel identification Auto store SEQ results Bias adjustment AUTO-CR Bias breakthrough Automatic frequency selector 23, 25 Bias frequency Automatic printing of sequence results 43 BNC sockets 12, 172 Automatic switch-off...
Page 201 CCIR weighting filter 22, 30, 58 Configuration E 116, 118 CCIR409-3 Configuration F 16, 110, 116 CCIR468 inverse Configuration G 43, 116 CCIR468-3 22, 40 Configuration H 116, 118 CCIR468-4 Configuration I CCIR468-4 Configuration J 56, 95, 102, 112, 192 CCITT O.33 sequence 63, 87 Configuration letters...
Page 202 D connector Difference signal DAC linearity Difference specifier Daisy-wheels Digital filter Data bits Digital to analogue converter Date editor Digitally generated Lindos test sequence Date heading Date on printouts Dimensions Date operation 13, 115 DIN plug Date setting DIN sockets...
Page 203 Dynamic range 58-59, 75, 110 Fast sweep Fault finding 157, 160 E? read error number 133, 179 Filter graphs 186-187 Early LA100 units Filter peak Early units Filter testing 57, 75-76, 110 EBU O.33 sequence 63, 87 29, 197 Echoes...
Page 204 FP set frequency presets Graph height 13, 116, 115 FR command Graph normalisation 13, 56, 115 FR set frequency Graph resolution Frequency code 134, 136, 183-184 Graph scale 13, 43, 116, 115 Frequency display Graph width 13, 110, 116, 115 Frequency Intermodulation 29, 197 Graphics...
Page 205 Keyboard test Impedance switching Impedance − setting in sequence IN interpolate 18, 50 In memory 1-5 next L? read level command Inbuilt sequences LA100 Audio Analyser Indos/Recommended default LA100 modules Inhibit autoranging LA100 versions Initial settings 12, 18 LA100C Initial volume...
Page 206 21, 107 Limit testing 37, 89, 93 Measurement commands Limiters Measurement function Lin4win Measurement level 54, 71-72, 188 Lindos default settings 10, 15 Measurement option 11, 19-20, 140 Lindos System Bus Measurement range Line amplifiers Measuring gain Line feed character...
Page 207 Missed segment 63, 82, 180 Noise segments 40, 73 Mixing consoles Non-volatile memory 10-11, 158, 162 Modem NORM Modulation distortion Normalisation 56, 95 Modulation noise on tape Normalise a weighting curve Modules NULL character 124-125 40, 65, 76-77, 107 Number of results memories 46, 82 Monitor loudspeaker 15, 168...
Page 208 Page length 13, 115-116 PR print sequence results Page mode 41-42 Pre-defined tolerances 92, 90 Parity 118, 123, 188 Pre-emphasis 35, 112 Partial reset Preset keys Pass/fail testing 45, 89, 93, 96, 98 Presets 18, 135-136 PASSED Print results Pause segment Print the date Pause until a key is pressed 85, 67...
Page 209 Quality control 89, 111 Register number 52, 143, 148 Quantising distortion 29, 111, 197 Registers Quasi-peak rectifier Registration card 14, 169 Question mark (?) 85, 94 Relative level 18, 43, 46 Quick Reference Card 10, 169 Relative measurements 32, 50 Relay faults Relay switching 78-79...
Page 210 characteristic) Segment F 74-75, 194 RIAA phono inputs Segment G RIAA-inverse Segment group RISC OS Segment H 76-77 RN set/read range Segment I RR? Read results Segment J RS reset Segment K 75-76, 95 RS232 compatible devices Segment L RS232 Connections Segment level RS232 serial port 14, 113, 121, 173...
Page 211 Sequence heading on printouts Size of unit Sequence input level SL2 serial printer lead 113, 169, 173 Sequence level segment SL7 printer lead 118, 173 Sequence number 65, 141, 143 Slash character (/) Sequence parameters Slow average of the rms rectifier Sequence Parameters: SP Slow noise measurement Sequence printout...
Page 212 Static precautions Technical support 14, 198 Steep filters 48, 50, 73, 110 Telecom Australia Version Stereo equipment Telephone line Stop bits 123, 188 Temperature range Stop printing Temporary test level Storage on disk 66, 121, 144 Terminal emulator Storing results in memory Test CD 29, 101, 103, 111 Studer A810...
Page 213 TL in manual mode TL on frequency response graph Uncluttered printout TL OUT 46, 50, 72 Units TL set test level Units used after switch-on Tolerance configuration 13, 92 Unix Tolerance definitions 11, 92-93, 90 Unmanned site Tolerance editor 89, 92, 96-98 UNUSED Tolerance information 41-42...
Page 214 Weighted frequency sweep 58, 108, 110 [<Hz] Weighting 58-59 [DIST] 24-25 Weighting curve 35-36, 137, 195 [Hz>] Weighting curves [L/R] 18, 25, 43, 52 Weighting editor [LISTEN] Weighting number [MUTE] Weighting on [*][2] [ON/OFF] 9-10 WF set waveform [ON/OFF][3] Wide graph [OPTION] Wiring audio leads [SEQ] key...

Lindos LA100 User Manual

1 Introduction

2 Manual Operation

3 Sequence Testing

4 User Defined Sequences

5 Tolerance Testing

6 Using Test Tapes and Discs

7 Applications Advice

8 Using Printers

9 Remote Control

10 Service Information

Appendix A Accessories

Appendix B Audio Sockets

Appendix C RS232 Connections

Appendix D Circuit Diagrams

Appendix E Error Messages

Appendix F Frequency Lists

Appendix G LA102 Filter Graphs

Appendix H FSK Header Format

Appendix I LA100 Versions

Appendix J Specification

Index

Quick Links

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Questions and answers

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Summary of Contents for Lindos LA100