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QTC-UMD / dds-sweeper

Raspberry Pi Pico interface for the AD9959 DDS
BSD 2-Clause "Simplified" License
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Amplitude Changes During Frequency Sweep #10

Closed ehuegler closed 2 years ago

ehuegler commented 2 years ago

For some frequency sweeps, the amplitude changes as the frequency is sweeping. amplitude-changes

dihm commented 2 years ago

Dang that looks cool.

In any case, you may want to consult the datasheet to see how flat the power output actually is with frequency. It is possible the changes are in line with what the AD9959 can actually do. You could also check this by just setting constant tone outputs and measuring amplitude versus frequency and see if the variations match.

ehuegler commented 2 years ago

I did not find anything in the datasheet but checking the amplitudes at constant tones did match up with amplitudes during sweeps.

dihm commented 2 years ago

Awesome! Glad it isn't anything too complicated. We'll probably want to note that dependence in the end (ideally with a measurement) since people can care a lot about that kind of thing.

ehuegler commented 2 years ago

Leaving this here for myself https://ez.analog.com/dds/f/q-a/27997/ad9959-understanding-and-accounting-for-power-loss-with-frequency