QA402 User Manual
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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.
The sample rate can only be changed while acquisitions are stopped. Changing sample rates will result in a
reset of the converters which might cause a slightly pop on the outputs. If you are working on high-gain circuits,
this might manifest as large output changes during sample rate changes. In general, the performance of the
converters is better at lower sample rates. If your measurement task doesn’t require frequencies beyond 20
kHz or so, stick to the 48K sample rate.
Click or press the “Press to Run” button to begin acquiring data. You can click it again to stop acquisitions.
There is a context menu associated with this button that will be discussed more below.
The Idle button will generate a constant sine at the Gen1 settings when the analyzer is NOT acquiring data. This
can be useful if you want to verify a lineup with a DVM. By default, when the analyzer isn’t acquiring data, the
outputs are muted.
The front panel I2S allows you to test I2S devices. The pinout of the front panel connector was shown
previously. The context menu here allows you to set operating parameters for the I2S, including bit depth and
sample rate.
