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synchronization across multiple AD9670

Question asked by JohannB on Apr 20, 2017
Latest reply on Apr 21, 2017 by AshrafS

I'm facing a major synchronization issue with multiple AD9670.

I'm using 4 AD9670 devices with common TX_TRIG+- and CLK+- signals.

 

* Rising and falling edge of TX_TRIG+ occurs at falling edge of CLK+

* TX_TRIG+ is in high state during 10 CLK+ period then in low state during a variable duration

* "StartCode" feature is used for sample synchronization.

* CLK+ is 25Mhz

* Multiband AAF is enabled (decimate by two)

* High-Pass filter is disabled

* Demodulator is disabled

* BB Decimator is disabled

 

When I use either Waveform Generator or Channel ID generator, AD9670 data outputs from all my device are perfectly synchronous.

 

However when I inject a common signal on all inputs of AD9670 devices. AD9670 data outputs are not synchronized (there is a random ADC sample shift between AD9670 devices).

 

Any ideas ?

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