4DSP Support Forum

Products => FMC Products => FMC150 => Topic started by: ericgch on April 12, 2013, 04:05 AM

Title: Minimum external frequency that can be used in FMC150
Post by: ericgch on April 12, 2013, 04:05 AM

Hi,


I would like to find out what is the minimum frequency that can be used as the external clock for the FMC150 card. Is 10MHz possible? If yes, what is the stability of this clock to my FPGA?


Thanks.

Title: Re: Minimum external frequency that can be used in FMC150
Post by: arnaudNL on April 12, 2013, 05:15 AM

Dear Sir,
As per FMC150 user manual Table 2, external clock input bandwidth is 3-800MHz so 10MHz should be fine. You might want to check A/D datasheet to know whether or not the A/D chip can have such a low sample clock.
Stability/quality of the clock have a direct impact on the acquisition (jitter, etc..) so an extremely good signal quality should be used for the clock. Normally you need to have expensive filtering otherwise effective number of bits will be affected.
I hope that helps,
Arnaud

Title: Re: Minimum external frequency that can be used in FMC150
Post by: ericgch on April 12, 2013, 05:33 AM

Thanks Arnaud for the reply.


One more question. If I use the external clock as an input reference to the internal clock. Will the internal clock be phase lock to the external clock?


Thanks.

Title: Re: Minimum external frequency that can be used in FMC150
Post by: arnaudNL on April 15, 2013, 04:20 AM

Hello,
I believe so.
Best Regards,
Arnaud