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From: | Marcus D. Leech |
Subject: | Re: [Discuss-gnuradio] Higher Accuracy Metadata Header? |
Date: | Thu, 21 Apr 2016 11:57:28 -0400 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 04/21/2016 11:41 AM, Michael Skaggs wrote:
I'm trying to time/sample synchronize RF recordings with two B200minis. I am using the detached Metadata File Sink in GRC. Both recordings are at 30MSps and both B200mini boards are synchronized to the same 1PPS signal.The precision of the timestamps from UHD should have a precision of whatever the master-clock is on the device--how are you interpreting the rx_time tag? It's two parts--a uint64 with the full-seconds portion, and a double-precision float for the fractional part.My issue is this, when I extract the data from the Metadata header file, the "rx_time" value is only accurate to 10e-4 seconds (0.0001s). Which, with a recording at 30MSps, this will only give me a sample alignment accuracy to 10e-4(s)*30(MS/s) = 30,000 samples.If I'm attempting to align the two recordings by samples or time, this is not nearly accurate enough. Is there a way that I can get more accuracy out of my metadata header or a way that I can synchronize the recordings of these B200minis?Thanks, Michael
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