Re: [Discuss-gnuradio] Time Granularity of USRP N2XX

Hi Harry,

as far as I know, the granularity of a time stamp is the sample duration
at the downsampled side.
As for the 10MHz: The 10MHz clock is used to derive different other
clocks, especially the rx ADC and tx DAC clocks, which are an order of
magnitude higher; bear in mind that when you request e.g. "5MHz samle
rate" you still get the 100MHz* samples of the ADC, but downsampled by a
factor of 20.

Please also bear in mind that due to physics, processing etc the
timestamp of the rx side is delayed to the actual reception of "that
sample", and that this delay is largely constant when receiving using
the same settings, but my change based on sampling rate and other factors.

Greetings
Marcus

*for USRP2 arch, if I remember correctly.
On 26.11.2013 13:04, Harry Zhang wrote:
> Hi,
> Since we can get receive time of rx_stream's first sample via rx tags, I
> have two questions about the time granularity. Given the internal clock
> is 10Mhz, is the time granularity 0.1us? The fractional second is stored
> double type. Does it mean the last digits of the fractional sec are invalid?
>
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