Wutong Electronic NWT4000-1 User Manual
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Wutong Electronic NWT4000-1 User Manual

Rf digital sweeper & analyzer
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NWT4000-2 RF DIGITAL
SWEEPER & ANALYZER
Manufacturer:
WUTONG ELECTRONIC
site：http://bg7tbl.taobao.com
TEL: +86134 2795 9750
Q
Q: 1630 2767
Email: bg7tbl@126.com
version: V2.0
date: 2014-10-20
This document is based on the original manual from the supplier, edited
and updated by Kurt Poulsen (OZ7OU)
The document and applied editing and updates devoted entirely to
document the NWT4000-2 25MHz-4.4GHz unit (using 2xADF4351 PLL's)but will
also be useful for the NWT4000-2 and NWT4000-1 series going from 138MHz to
4.4GHz (using 2xADF4350 PLL's). However, the latest NWT4000-2 where the
SMD connector are on top of the PCB (and not at the edge) has improved
screening and far better dynamic range. Watch our when building it into a case
to use a plastic case. Using a metal case will most likely give elevated noise
floor by several dB in the GHz region.
Watch out that you do not purchase the version in a case with two SMA
connectors and a Green LED in between (believing it is a NWT4000 version), as
it most likely will only have 1 PLL (ADF4350 for 138MHz version and ADF4351
for 25MHz version) and thus only is a signal generator and spectrum analyzer,
not being able to sweep the frequency response of devices.
May 2015 edition
USER MANUAL
1

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Summary of Contents for Wutong Electronic NWT4000-1

  • Page 1 The document and applied editing and updates devoted entirely to document the NWT4000-2 25MHz-4.4GHz unit (using 2xADF4351 PLL’s)but will also be useful for the NWT4000-2 and NWT4000-1 series going from 138MHz to 4.4GHz (using 2xADF4350 PLL’s). However, the latest NWT4000-2 where the SMD connector are on top of the PCB (and not at the edge) has improved screening and far better dynamic range.
  • Page 2 List of content: Overview NWT4000-1 and NWT4000-2 page 4 Instrumental composition and technical characteristics page 6 Conditions of use page 8 The basic design page 9 1. The hardware connection reference and software guide page11 1.1 Functions not supported for NWT1400 in the WinNWT software page14 2.1 and 2.2 Logarithmic Y scale sweep frequency settings...
  • Page 3 10.1 Wattmeter Functions page48 10.2 Wattmeter calibration page48 10.3 Saving a single or several Wattmeter measurement page52 11.1 VFO signal level on the output page54 11.2 VFO frequency setting page53 12. Frequency calibration page55 Appendix 1: FAQ page59 Appendix 2: return loss, reflection coefficient, voltage standing wave conversion tables.
  • Page 4 Overview NWT4000-2 Sweep Features ★ 35MHz-4400MHz 35MHz - 4400MHz range of fast and accurate measurement ★ Dynamic range: >70dB ★ Software calibration function to reduce the system error ★ Directly display 3dB, 6dB, 60dB bandwidth ★ Curves of maximum minimum value display，with cursor ★...
  • Page 5 Overview NWT series digital virtual frequency sweeper is a high intelligent RF frequency analyzer. The equipment is composed of MCU, RF detection, RF generator(s), and the circuit board contains the linear detection, log detection, completely analyzing systems for amplitude versus frequency characteristics.
  • Page 6 Instrumental composition and technical characteristics Instrument: NWT Series sweep instrument 1PCS USB cable 1PCS AC (100-240V) to DC 12V power supply 1PCS DISC 1PCS SWR BRIDGE (OPTION not included) 1PCS 40db ATT (OPTION not included) 1PCS 6db ATT (OPTION not included) 1PCS The version with improved screening as shown above was purchase from cart100...
  • Page 8 Technical characteristics (comparison chart to other products by WUTONG ELECTRONIC) The basic parameters type frequency step line power NWT25-EX 2k-25M >70dB 12V/0.4A 0-50dB NWT25-USB 2k-25M >70dB USB(5V/0.4A) 0-50dB NWT70-EX 50k-85M >70dB 0-0.7VRM 12V/0.4A 0-50dB NWT70-USB 50k-85M >70dB 0-0.7VRM USB(5V/0.4A) 0-50dB...
  • Page 9 Installation and storage Conditions of use NWT series digital virtual frequency sweepers are using USB or external DC 12V power supply, and need to be kept away from strong radiations (high power switching power supply, high power RF emission). Operation temperature: 0-40 degrees centigrade. Preheating: NWT series digital virtual frequency sweepers are most accurate after 30 minutes preheating prior to measurement.

  • Page 10: Hardware Configuration

    The basic design Hardware configuration 1.1： Theory: The block diagram only for reference, some sweepers does not have att. and amplifier. The NWT4000-2 contains addition circuitry such as two PLL signal generators but does not contain any attenuators or Amplifier. Hardware connect With the DC-12V and RS232/USB connected, external devices are connected to the SMA connectors.
  • Page 11 Top view (note new position of SMA Input and Out) Bottom view (with latest improved screening)
  • Page 12 The hardware connection reference map The software guide Software installation and configuration. Dependent your operating system, the USB driver might be installed automatic. Let the computer search on the Internet and it might take several minutes. Otherwise find on the supplied disk relevant drivers: If not installed automatic then: Install USB driver by running ftdi_ft232_drive.exe for WIN7, WIN8 or use inf file install driver.
  • Page 13 Original Chinese startup settings (remark the app cn.qm extension to winnwt4.exe) The line “G:\Program Files\AFU\WinNWT\winnwt4.exe" app_cn.qm Changed to: “G:\ProgramFiles\AFU\WinNWT\winnwt4.exe” app_en.qm available close and restart the program and the English menu is available. The use of English version recommended but Chinese cn), Spanish (es), Hungary (hu), Netherland (nl), Polish (pl) and Russian (ru) language may be chosen.
  • Page 14 The port number to remember in this case is COM4. When installing the driver, on different computers the COM port number will be differ In WINNWT software "Settings", "Options", select the corresponding COM port, and click "OK". Select COM port Choose the correct com port and if successful, you will see the hardware firmware version.
  • Page 15 When using NWT3000, NWT4000-1 or NWT4000-2, you must set frequency multiply to 10 rate in Settings/Options. Note the settings for start and stop frequency where stop is negative. Note also the max sweep setting. If One Chann. tickmark in Channels is removed then you have two channel operation, e.g.
  • Page 16 In the mode selection box under sweepmode only sweepmode, SWR and Impedance-|Z| is supported. The remaining selection cannot be used as they are. Attenuation and Frequency Zoom cannot be used. Display shift OK for the dB Y Axe. Interrupt (uS) = rest time for each sample For the Graph-Manager all functions supported For VFO: Attenuator 0-50dB , Set IF for Sweeping and IF setting has no function.
  • Page 17 Another is the single scanning where only one scanning performed for the number of samples. For changing frequency settings, scanning numbers/number of samples and other parameters, you must click on Stop before change settings. The scan delay for each point/sample of the output frequency, are long latency for power measurement.
  • Page 18 Before starting measurement the Instrument should be calibrated. It is recommend to initially using the software on the supplied disc called COM assiter.exe. It performers an excellent flat calibration of you particular hardware and the result is saved into the hardware. However the levels from -10dB to 0dB is nonlinear due to about 4dB compression in the internal reception mixer and/or logarithmic detector.
  • Page 19 Insert a 40dB attenuator in the Transmit path (at the SMA Output) and click OK Subsequent you are promptedd to insert a 0dB attenuator or select differently a user defined att. here stepped down to -6dB. The sweep is performed automatic with 9999 samples.
  • Page 20 When accepted by a click on OK the trace is jumping to it correct position -6dB. If Y scaling change to 0 and -10dB we see it bang on -6dB (small image below) If we enter the 40dB att. and run a single scan, we will see it is flat on -40dB from 35MHz to 4.4GHz If we connect the Output and Input directly and run a sweep we see the degree af compression in the mixer.
  • Page 21 2.4 Blending cursor data into the trace image and saving it It is possible to blend cursor data into the trace image. First of all press the numeric key from 1 to 5 on the keybord and click on the frequency position where you want the particulator cursor number to be placed.
  • Page 22 You may edit first line ;no_label prior to “einblenden” as seen on the next image below.
  • Page 23 Above measurement done with two 5cm long male SMA SMA cables connected from the PCB SMA connector to a front panel with female female SMA adaptors used as the TX and RX connections. As previous described the NWT4000-2 has best dynamic range if mounted in a plastic case.
  • Page 24 2.5 Typical display of sweep measurements WiFi Filter single Channel...
  • Page 25 A single scan curve, the curve is a curve of a 21.6M filter 2.6 Saving of Graphical screen The Grapical Screen can be saved and re-loaded by clicking on Graph. The format is *.hfd and saving can happen to a folder at your choice.
  • Page 26 The below mentioned function about frequency zoom is not supported by the NWT4000 series and only mentioned for reference. 2 times zoom settings For a measurement, the available frequency scaling functions are magnified 2 times, reduced 2 times, fast frequency response measurement device. The + button 2 times magnification operation, bond was reduced 2 times operation.
  • Page 27 Inverted triangle marker displayed Frequency of the 5 screen markers displayed, and the signal level in dBm...
  • Page 28 2.9. The Y settings in the Graphical Display The Y axis scaling function: The Ymax signal level on the Graphical display is selected in the drop down list. Standard level is 20dB but 0dB more relevant for the NWT4000 family Ymin signal level on the Graphical display is also selected in a drop down list, generally choose -90dB.
  • Page 29 Measurement of a 49.55MHz Quartz Crystal 2.10 Bandwidth display settings The measured curve, can directly have in the Graphical Display the 3dB, 6 and 60dB bandwidth shown as lines and the data shown in the text field with additional Q value and rectangular coefficient.
  • Page 30 The measured curve Display of 3dB bandwidth, Q value and related parameters 6dB bandwidth and 60dB bandwidth, is similarly rectangular coefficient. Markerlines are used to display the dotted line bandwidth in the Graphical Display area, for better recognition of bandwidth parameters. B3dB Inverse is used for trap measurement.
  • Page 31 2.11 Multi curve display management Graphic-Manager Get；Active channel；Show Graph After a measurement, the curve can be stored and controlled by the Graphical Manager. The current trace is acquired by a click on the Get button. Then tick the active channel number and tick Active for Showing Graph. Version 4.11.09 Graph-Manager Version 4.09.07...
  • Page 32 Version 4.11.09 Graph-Manager Version 4.09.07...
  • Page 33 3 traces selected for presentation for a 500MHz diplexer. Low/High pass and Isolation (red) The Graphical Manager is quite handy for measuring e.g. diplexers. As the first graph for this diplexer (specifiied as 0-500MHz/800-1300MHz) showed many spurious responces in the 35 to 500MHz region. As the NWT4000 deliver squarewave signals as the output signal, the 3.
  • Page 34 Linear scan settings (unsupported) Note: Some type of equipment do not have this function and are not supported by NWT4000 family of products. 4. SWR 4.1 SWR Measurements Enter SWR mode For SWR measurement an external brídge is required. Connect the bridge. The bridge input is connected to the NWT scanner RF output, The bridge connected with the NWT scanner RF input.
  • Page 35 In the shown example below the Bridge used is a Narda bidirectional coupler model 3022 specified for 1 to 4GHz and selected frequency setting 1 to 4.4GHz. When running a SWR sweep the number of samples is e.g. changed to 999 for a faster sweep, as the Calibration always uses 9999 samples.
  • Page 36 Black trace without any attenuator in the TX path and red trace with 10dB attenuator inserted. The bridge output is -20dB below input signal and as there is ample sensitivity in the RX so this 10dB attenuator does not harm. Please observe the SWR range can be changed with the drop down list.
  • Page 37 4.4 SWR Measurements examples The GSM900 band between marker 1 and 2 has too low a resonance and then too high SWR but GSM1800 inside marker 3 and 4 quite OK The picture below is a measurement of a UHF low band antenna. The resonant point at about 430M, SWR about 1.1.
  • Page 38 The text area shows the standing wave maximum, minimum Another case of a 3.5GHz 10dBi vertical antenna with and without 4m feed line cable 4.5 Bridge performance investigation Is is also posssible to examine the Bridge for proper operation to be used for SWR measurements.
  • Page 39 The NWT4000 output fitted with a 10dB attennuator to stabilize the output impedance closer to 50 ohm. Black trace input to output. Red trace output terminated with short and green with open and thus with full reflection). Blue trace when output terminated with 50 ohm (and thus no reflection).
  • Page 40 5 SWR_Ant mode SWR antenna measurement with coax feed line This function is not compatible with the NWT4000 family. Setting the cable parameters Wrong results obtained if used 6. Impedance - |Z| 6.1 Numerical Impedance measurements You need to use the bridge to measure the numerical impedance. During the measurements you need to insert a 50 ohm resistor in series with the DUT.
  • Page 41 After measurement read directly from the chart the numerical impedance values During measurement a 50 ohm resistor in series with bridge and DUT required. Measurement of a 65 ohm resistance.
  • Page 42 Measuring a device connection methods Filter test method 1 The following diagram is suitable if the filter input and output impedance is 50 ohm, if the filter impedance has mismatch, the measurements are prone to error in passband bandwidth and big fluctuation of measurement inaccuracy might exist. Methods 1, suitable for filters with input and output impedance of 50 ohm.
  • Page 43 RF transformer measurement method 1 RF transformer measurement method 1 RF transformer measurement method 2 RF transformer measurement method 2...
  • Page 44 An antenna measurement method For NWT series of frequency sweep meter you need an additional external bridge for antenna SWR measurements. A reference circuit are as follows: ANTENNA RF OUT NWT4000 RF IN NWT4000 diagram of SWR bridge Because the bridge needs to be a precision device, not easy to make yourself, you are recommended to buy a finished bridge.
  • Page 45 The small capacitance, inductance measuring method Testing of unknown L or C 7.7 Amplifier amplitude frequency characteristics measuring method If it is a small power amplifier, and the output power is less than 10dBm, you can directly connect to the sweeper’s RF OUT and IN without to destroy NMW4000 series. However as seen before the INPUT saturates for a lesser amplitude so attenuator needed.
  • Page 46 Power amplifier test 1 Power amplifier test 2...
  • Page 47 7.8 Notch filter test For a trap LC parallel circuit, available method for testing shown where a dip seen in the sweep mode when connected between RF OUT and RF IN. LC parallel notch filter measurement connection method 9 Spectrum Analyzer 9.1 Spectrum Analyzer functionality The Spectrum Analyzer is a simple spectrum analyzer which is utilizing one of the PLL’s in the NWT4000-2.
  • Page 48 Spectrum of the 100MHz signal when -6dBm, -16dBm and -26dBm applied to the input It is clarly seen that all sort of spurous signal generated and mesurement of the signal generators harmonics not possible. First by comparing the -16 and -26dBm sweeeps we can trust the measurements of 2.
  • Page 49 You might have saved the sweep calibration in the default file name defsonde1.hfm 10.2 Wattmeter calibration Note: For NWT4000-1 and NWT4000-2 the VFO must be set to the frequency to measure. Now select Wattmeter and apply a signal source, with known dBm amplitude, to the NWT4000 Input port.
  • Page 50 wrong as the Wattmeter not yet calibrated. Below the dBm read out is a drop down list which indicated is is possible to compensate for variation in the sensitivity of internal detection circuitry across the 35MHz to 4.4GHz range, but as seen the list is initially for a quite different product, so the calibration needed both to edit the drop down list and the sensitivity and the procedure described below When for Wattmeter we click on ”Measurement”...
  • Page 51 The input to the NWT4000-2 when delivered from the NWT4000-2 output is measured to be - 2.36dBm with a Hewlett Packard powermeter 437B and 8481A power sensor. As the output of the NWT4000-2 is squarewave the theoretical fundamental is 0.707 or 3.01dB lower in level then -5.37dBm.
  • Page 52 The editing thus results in a new visual drop down list If you do not have a wave generator then use the settings in the table. It is better than nothing done.
  • Page 53 Interesting to see the peak at 1.1GHz which is reflections inside the PCB of the NWT4000-2 as well a 5 cm SMA male male cable can create 1.5dB attenuation at 2.8GHz. Also observe that when using an external 20cm SMA male male cable that standing waves develops above 1GHz and how a 10dB attenuator is stabilizing the frequency response with the 20cm cable present.
  • Page 54 As there is inserted an 10dB attenuator in series it can be compensated for by the “Attenuation (dB)” setting. Select for each measurement “Write to Table” When finish with the measurements select Save Data and chose the location for saving and provide a file name.
  • Page 55 11. The VFO mode 11.1 VFO signal level on the output The output is documented in section 10.2 page 52 as the level into 50 ohm 11.2 VFO frequency setting The frequency setting is quite simple to understand and need no further explanation. They is selextion possiblity for five quick access frequencies which in combination with the tick in VFO-Frequnecy x4 for “I/Q Mixer”...
  • Page 56 (Note!! Read appendix 4 if you counter only can measure 100MHz) 12.1 Prepare a 1GHz frequency counter, allow enough warm-up time, for NWT4000 electric power up for 30 minutes（NWT3000，NWT4000-1.NWT4000-2 used 1GHz calibration, for others models use 10MHz calibration） 12.2 Enter VFO mode , output 1GHz/10MHz Input 1GHz/10MHz Use frequency counter to test nwt4000 output frequency Test output frequency in this case 999.990 330MHz...
  • Page 57 Enter option Enter OPTION Input frequency counter frequency with units in Hz, press OK, then the frequency calibration is complete, result as shown below.
  • Page 58 Input test frequency Frequency reading has changed Frequency calibration complete.
  • Page 59 The user should pay attention to: 1. Read the manual at first. 2. NWT series digital virtual frequency sweeper is a precision instrument and has been vibration tested, splash proof, and corrosion resistant. 3. Do not short circuit signal the output port, as easy to cause internal damage to parts.
  • Page 60 USB which performs the calculation of data and present the curves. It can act as VFO (signal generator) and as a power meter and are lighter than the old sweeper. NWT4000-1, NWT4000-2 can be used as a simple spectrum analyzer.
  • Page 61 4, Can the sweeper test a duplexer and how to test ? A duplexer is a filter. The NWT sweep analyzer input is connected to the output of the duplexer antenna connector and the NWT OUT connected to the Low or High antenna connector (the unused connector terminated with 50 ohm).
  • Page 62 GSM band duplexer curve 5，How to test antenna ? Used a SWR bridge or a three port connector. SWR bridge test: Swr bridge, RF output...
  • Page 63 Diagram When using the SWR bridge you can measure in the transmission sweep mode, as a qualitative measurement, but you need to pay attention, frequency sweep analyzer can only use the RF Output of the Bridge, not the Bridge band detection output.
  • Page 64 SWR bridge test of UHF antenna with three port connector Use a three port connector replacing the SWR bridge, and you can test an antenna , but only for a qualitative test just a showed above SMA three port 6. Attention when using the Sweep analyzer. When connected to the computer and the DUT, then you need to pay attention that grounding is good, to prevent too high level input to the detection circuitry, otherwise it will damage the detecting element.
  • Page 65 normally of 3 dB will be adequate but if you want to have more precise, they can be replaced by 6-10 dB attenuators or even higher dB levels but the disadvantage is loss of dynamic range. 10. Some component curves tested with the NWT4000-2 equipment HP 5086-7051 LPF Mini NHP-700 HPF...
  • Page 66 REACTEL 1.1-1.15G BPF BPF24-806A...
  • Page 67 Appendix 2: return loss, reflection coefficient, voltage standing wave conversion tables...
  • Page 68 Appendix 4 NWT4000 Sweep flatness and frequency calibration 1. NWT4000 sweep calibration steps Appendix 4.1 Flatness calibration ATTENTION: If curves is not flat or the linearity from -10dB to 0 dB is too compressed, then insert two 3dB attenuation to input and output both when instrument is used and when calibrated as described below.
  • Page 69 Open COM port, input 8F 60 5. Click on Send...
  • Page 70 6. According to the prompt, “short circuit” input output by connection a SMA male-male test cable between input and output, and when completed click on Send 7. Insert 40dB attenuation and when done click on Send 8. Calibration complete.
  • Page 71 9. Calibration complete the curve is flat for 0 and 40dB...
  • Page 72 Appendix 4.2 Frequency calibration 1. Prepare a 1GHz frequency counter, warm-up time enough, NWT4000 electric power up for 30 minutes 2. Enter VFO mode ,output 1GHz 3. Used frequency counter test nwt4000 output frequency...
  • Page 73 4. Options: 5. Input frequency counter frequency with unit Hz，press OK, frequency calibration complete。...
  • Page 74 Special tricks if your counter does not go to 1GHz: If you counter does cover 100MHz then use a gate time of 10sec to read the frequency with at least 10Hz resolution , set the VFO to 100MHz and write down the measured frequency e.g. 99.99931MHz .
  • Page 75 e.g. 999999310Hz and set the VFO to 1GHz and enter 999999310 into the DDS (PLL) Clock (Hz) in the Settings/Options/ menu point. Then the frequency is calibrated to within 1kHz at 4.4GHz. When measuring the 100MHz output after calibration You may experiment with the 1 Hz settings to get closer to 100MHz.

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