Fluctuations in ADC regular simultaneous mode

[rags]

Posted on June 11, 2014 at 15:08

Hi Everyone,

We are developing a power monitor system. In that we are using ADC Peripheral in Regular Simlutaneous mode. we are taking 256 samples per cycle of 800 Hz. and we are trying to capturing signal from ADC1's channel 0 and ADC2's channel 1 simultanously,  but we are getting too much fluctuation while capturing and we are feeding signals from Function Generator. Waveform is attached with this. Hope you help us as soon as possible.Thanking you.. #adc-fluctuation-problem #adc-regular-simultaneous-mode #adc-regular-simultaneous-mode #adc-regular-simultaneous-mode #adc-fluctuation-problem #adc-fluctuation-problem

[rags]

Posted on June 16, 2014 at 08:22

Hi Hal,

We tried for 13.5 cycles as you said. but still problem remains same.

[chen]

Posted on June 16, 2014 at 17:52

Hi

The last attachment still shows ADC1 and ADC2 receiving the same signal. If ADC1 and ADC2 are being fed from 2 different signal generators - we expected to see 2 seperate non linked sine waves.

[raptorhal2]

Posted on June 16, 2014 at 21:23

It looks like we are down to concluding that something is generating noise internally to the chip when both ADCs are operated simultaneously. If simultaneous sampling is absolutely required, try another board or chip model. If a small phase difference between samples can be accomodated, try fast interleaved or slow interleaved mode. If that doesn't do it, try sequential samples using the same ADC.

Cheers, Hal

[rags]

Posted on June 24, 2014 at 09:03

Hi sung,

Thanks for reply... Will see to it properly whats happening and get back to you..Regards,Mikey

[rags]

Posted on June 24, 2014 at 09:04

Hi hal,

Thanks for reply... Will Check with different board once then.Regards,Mikey