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Re: [Discuss-gnuradio] USRP2 - external clock pps python example
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From: |
Matt Ettus |
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Subject: |
Re: [Discuss-gnuradio] USRP2 - external clock pps python example |
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Date: |
Wed, 13 Apr 2011 11:46:45 -0700 |
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Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.15) Gecko/20110307 Fedora/3.1.9-0.39.b3pre.fc14 Lightning/1.0b3pre Thunderbird/3.1.9 |
On 04/13/2011 11:31 AM, Burak TUYSUZ wrote:
> It does not say if it is the falling edge or the rising edge of the
> pps. Is it possible to specify that or is it defined?
>
The PPS is *always* recognized on the rising edge of PPS. To change
this you would need to change the FPGA. The change would be trivial,
but I don't think that's what you'd want, since the rising edge is
essentially a universal standard.
The setting which Josh mentions allows you to choose whether PPS is
sampled on the rising or falling edge *of the clock*. This is important
because there are varying phase differences between the PPS and 10 MHz.
You should connect your source and see which way works better for your
particular source.
Matt