I am using an AD7794 in an application where I measure resistances. When acquiring many consecutive samples in continuous mode I see occasional spikes ( every couple of 10000 samples) in the signal which I attribute to the ADC. Please see the attached plot. The discretization in the plot comes from formating the output to 3 decimal places.
The setup is as follows:
* for circuit see attachment
* DIN is tied high between write operation
* SCLK is high in the idle state
* Sample rate 470 Hz
* continuous mode
* external (ratiometric) reference
Any advice on what might cause this effect ?
Thank you and best regards
I seem that the spike were due to a very noisy TTL RS232 converter IC .... after switching it off during ADC the spikes disappeared ...