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DAC output level over frequency

Posted: Sat Jan 13, 2018 3:01 am
by ctrofin
When running the 'Oscilloscope & Generator' app, I noticed that the DAC'c output amplitude varies with frequency with a level exceeding twice the set amplitude somewhere in the middle of maximum bandwidth.

So, at 10KHz and a level set to 0.5V it outputs 0.5V/10KHz, changing just the frequency to 20MHz, will output a voltage level of 1.6V. Going to 40MHz will output ~0.5V/40MHz. This is on 'Low Voltage' jumper setting.

Generating a frequency sweep from 1 to 40MHz using the SCPI API, shows that there is a amplitude hump in the middle of the bandwidth, which saturates the ADC if DAC-to-ADC loopback is used.

This is a brand new board. Is there a calibration/setting I should do to correct this or should I suspect something being wrong with the board?

The output level/frequency was measured on a Tektronix scope.

Thank you,