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ad9234 outliers

Question asked by phammer on May 12, 2016
Latest reply on Jun 3, 2016 by phammer

Hi,

I'm using an AD9234 ADC and I'm sampling a dc coupled static signal (low noise). I implemented a statistic for all the samples I receive from the adc in one second (mean, noise, minimum sample value, maximum sample value). The mean-value of my signal is 144LSB and the noise is about 1.5LSB. The mimimum and the maximum sample I receive is normally about 130LSB(min) to 160LSB(max), but sometimes (about every 600seconds) I receive one outlier sample with a value of about 250lsb. The samples before and after this outlier are about 144lsb. I use an anti-aliasing-filter with a bandwidth of -3db@110MHz. The internal termination of the adc is set to 200ohm and the input buffer control is set to the default value of 2.5x buffer current. I tried to change the termination to 50ohm and the buffer current setting to 8.5x but it didn't have an effect on the outliers.

I have also tried to activate the adc internal test modes to see if there is a problem with the jesd204 interface but I didn't see any outliers with the activated test mode.

 

Are thee any other settings or tests I can make?

 

Best regards,

Peter Hammer

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