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Koheron / koheron-sdk

SDK for FPGA / Linux Instruments
https://www.koheron.com/software-development-kit/
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RF ADC noise issue #585

Open hansmdau97 opened 10 months ago

hansmdau97 commented 10 months ago

Hi, there

While measuring data using the ADC-DAC-DMA instrument of the ALPHA250, I noticed too much flicker noise in the low frequency band.

Therefore, when I measured the data without the input of ADC0, the data appeared as shown in the figure. ( at 10 Hz to 1MHz)

ADC0

Did I make a mistake in my measurement? Or is it caused by the DC offset of the default ADC0? If so, can I control the DC offset?

tvanderbruggen commented 10 months ago

We typically have about 25 nV/rtHz of spectral density at 100 kHz, this seems to be about what you observed.

Concerning the DC offset, did you terminate the ADC input with 50 Ohm ?