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Related Manuals for QuantAsylum QA40 Series
Summary of Contents for QuantAsylum QA40 Series
- Page 1 QA40x User Manual Revision 1.20 February 2022...
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Page 2: Safety Notice
This document and the associated computer codes, hardware design and hardware configuration files are copyright © 2011 - 2021 by QuantAsylum USA LLC. All rights are reserved. You may share the associated documents in PDF format freely. The EXE programs and provided APIs codes are use only with QuantAsylum... -
Page 3: Table Of Contents
QA402 User Manual Contents ....................................1 Safety Notice ................................. 2 Limited Warranty ..............................2 Legal ..................................2 Online Documentation............................5 In the Box ................................5 Important Things to Know ............................ 5 Model Number ..............................5 Ground Reference ............................. 5 BNC Input Voltages ............................5 BNC Output Voltages ............................ - Page 4 QA402 User Manual System Annunciators ............................14 Control Groups ..............................16 Display Options ............................... 16 Axis Settings ..............................17 Acq (Acquisition) Settings ..........................19 Weighting ................................ 20 Windowing ..............................21 Measurements ..............................21 Generators ..............................23 Sine Generation ............................24 Multitone ..............................
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Page 5: Online Documentation
Additional sources of information can be found at the Github Wiki for the QA40x, and the QuantAsylum Forum. In the Box The box contains a QA402 Audio Analyzer. We do not ship cables with our products. The software for the products may be downloaded from GitHub. -
Page 6: Qa40X Output Voltage Offsets, Click And Pops
We welcome all questions, no matter how simple. Analyzers are complex products, and your questions help us improve our products. -
Page 7: Expansion Connector
QA402 User Manual Atten LED: This indicates the QA40x input attenuator is active. If you are going to connect the QA40x hardware to large signal, it is best to pick one of the higher input ranges that enable the input attenuator as you attempt to learn the characteristics of the signal you are measuring. -
Page 8: Understanding Differential Measurements
QA402 User Manual on the L- input, and treat the L+ input as a single ended input. If you do not use the input terminator, then you will see some thermal noise from the unused input resistor, which will raise the overall noise floor. Understanding Differential Measurements Differential measurements can create confusion even among very experienced engineers. -
Page 9: Bnc Outputs
QA402 User Manual Excessive input voltages can also stress the 470 ohm input resistor. The purpose of this resistor is to limit current in fault conditions, and it’s a special composition resistor that can cope with very high pulse currents. But under extreme conditions the resistor might open to protect the inputs. -
Page 10: Plugging In Your Hardware
QA402 User Manual Plugging in your Hardware The QA40x application requires you to specify the hardware model you are connecting. In the lower left of the application, you will see a message indicating which hardware is expected. You can change that in the File-> Device menu option. -
Page 11: Qa40X Basic Controls
QA402 User Manual Alternately, you can use the up/down arrows to scroll the panel normally, or page up/down to scroll the panel more quickly. The buttons will illuminate when the mouse passes over the button unless the button is disabled. This gives you a chance to better read the text when is normally dim when the button is in the un-pressed state. -
Page 12: Measurement Display Area
QA402 User Manual Measurement Display Area At the top of the trace display is the measurement display area. Measurements can be added by clicking in this region: Clicking will bring up the Add Measurement dialog box:... - Page 13 QA402 User Manual You can filter on measurements by entering text in the Filter Measurements dialog. For example, if you enter “thd” (case insensitive) the test choices will collapse to the following:...
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Page 14: Trace Display Area
QA402 User Manual If you wish to add a title to your graph, that can also be done in the Add Measurement dialog in the text box at the bottom of the dialog. You can specify up to four lines of 80 characters each. Trace Display Area The graph display area can have a few areas of added information, in addition to the measurement traces. - Page 15 QA402 User Manual ADC Overflow: Indicates the ADC had packets, but the USB didn’t take them in time and so may have been lost. Sometimes, this message can be a bit pessimistic and what was flagged as an error might not have been an error.
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Page 16: Control Groups
QA402 User Manual Control Groups The control panel on the left side has several groups of controls. Inside each group, there are two control types. We can see an example of this in the Axis Settings control group. On the left side you can see four buttons, and on the right side you can see a pair of up/down controls. -
Page 17: Axis Settings
QA402 User Manual Axis Settings The Axis Settings control group is shown below: The dBV button will display the frequency domain in the absolute units of dBV, while the dBr button will display the frequency domain relative to a signal you specify. The context menu for the dBV button is shown below: In this dialog, you can specify the units for the Y axis. - Page 18 QA402 User Manual When using the dBr display option, you need to specify your reference amplitude. This dialog allows you to quickly specify the reference using the display peak or the left measured at 1 kHz. Or you can specify the dBV value that should map to 0 dB.
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Page 19: Acq (Acquisition) Settings
QA402 User Manual The “X Log” button is similar, except it selects a logarithmic X axis. The dialog box options are similar. Acq (Acquisition) Settings The Acquisition Settings control group allows to set FFT sizes and averaging. Larger FFTs will take more time to acquire. Generally, it’s good to work with an 8k to 32k FFT for most work. Some measurements, such as THD+N will show little benefit at higher FFT settings. -
Page 20: Weighting
QA402 User Manual Weighting The Weighting controls allow to you apply standard “A Weighting”, or a custom User-weighting function. The latter can be useful for “flattening” an RIAA response curve, notching out undesired frequencies or compensating for known DUT deficiencies. The context menu for the USER1 weighting is shown below:... -
Page 21: Windowing
QA402 User Manual Windowing The Windowing controls allow to select the window type. You can click on the “?” mark for some hints on the different types of windows. In general, if you are using the DAC on the QA40x as the stimulus, then RECT or HANN windowing is preferred. - Page 22 QA402 User Manual For THD and THD+N, the context menu is as follows. The Measurement Start and Stop frequency is the same as the RMS setting. That is, you set a measurement start and stop frequency globally, and that is used for all measurements that need a measurement start and stop specified.
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Page 23: Generators
QA402 User Manual Generators The Generators control group is show below: From this group, we can select one of four modes of operation. (Sine Gen, Multitone, White Noise and Expo Chirp). Overall, the QA40x has 5 modes of operation, as shown in the block diagram below. The fifth mode of operation (“User Provided”) is a programming mode that isn’t accessible from the front panel. -
Page 24: Sine Generation
QA402 User Manual As the block diagram above shows, the Sine mode allows one or two Sine generators to be active, each with full control over frequency and amplitude. The dual tone is useful for IMD measurements. The Multitone sine mode allows dozens or even hundreds of sines to be generated, with each sine having the same amplitude and related to the neighboring sines. -
Page 25: Multitone
QA402 User Manual Octave sensitivity you specify. So, if you are at 1 kHz, and you have specified 1 octave, then each click of the FREQ1 UP button will result in changes that step 1 kHz, 2 kHz, 4 kHz, 8 kHz, etc. If the “Use Hz”... - Page 26 QA402 User Manual Notice above that while we have 0 dBV total RMS, each sine is about -20 dBV. The sum of all these sines, however, is around 0 dBV. But the real challenge is in the time domain. Notice that even though each sine is just 100 mV in amplitude, the total output level has exceeded 4V peak in places.
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Page 27: White Noise
QA402 User Manual White Noise White noise generation doesn’t have a context menu. It’s simply a stream of random numbers where the RMS measured will usually match the RMS you have specified. Sometimes the RMS will be a bit higher, other times a bit lower. - Page 28 If you have a mask file prepared, you can load the mask file and opt to display a pass or fail message if the frequency response deviates outside of the mask limits. Mask files are very simple to create. An example: # QuantAsylum Mask File # Frequency, Minimum Pass Value (dB), Maximum Pass Value (dB) 100, -1.0, 1.0...
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Page 29: Full Scale Input
QA402 User Manual If the measured response is within the mask boundaries, you will see PASS displayed, and FAIL display if not. Masks can be as complex as required to capture the expected behavior. You can create them manually, as above, or use an automated measurement to export a mask. -
Page 30: Run/Stop
QA402 User Manual the input sees a higher source resistance which will manifest as higher input noise due to the current noise of the input opamp. You can click on the “?” graphic to learn more about the preferred input ranges. Run/Stop The Run/Stop control group allows you set sample rates, start and stop acquisition, define idle mode behavior and control the front-panel I2S operation. -
Page 31: Run/Stop Context Menu
QA402 User Manual Run/Stop Context Menu The context menu for the Run/Stop button is shown below. Triggered Acquisition The Triggered Acquisition is discussed in more detail on the QA40x Wiki article Triggered Sweeps. -
Page 32: Cursors
QA402 User Manual In short, this mode is useful for DUTs that do not have an analog input. By playing a special WAV exported from the QA40x application, you can trigger a sweep and learn the frequency response from of the DUT using a chirp. - Page 33 QA402 User Manual The cursors also work in the time domain, and the legend will also show 1/period allowing you to quickly learn the frequency at a given point in time.
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Page 34: Other Items
QA402 User Manual Other Items Soft Keys There are several useful softkeys that can accelerate workflow: Function “Space” Starts or stops acquisitions “ctrl+space” Runs a single acquisition. This can be useful if you are conducting a “smoke test” on a very high power amplifier. By selecting a very small FFT, you can emit a single short burst of sine. -
Page 35: Command Line Options
Command Line Options The following command line options are available for the QA40x application: Enables logging to a file name comprised of the date and time, and placed into the directory “MyDocs\QuantAsylum\QA402\Log directory” Enables console display Automated Tests The Automated Test menu items allows many tests to be completed automatically, based on parameters you enter.
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