Re: [Discuss-gnuradio] Hardware "jitter", particularly USB

[Martin Braun]

We call this the two-clock problem, and yeah, it's quite common.

Cheers,
M

On 03/14/2016 11:14 AM, Gregory W. Ratcliff wrote:
> GnuRadio community,
> 
> I have been using various hardware interfaces to gnuradio lately.
> In the simplest example, I noticed an issue with Funcube Pro Plus with
> broadcast wideband FM (about 4 GRC blocks) whereby it would consistently
> underflow, even though every rate appeared to be perfect.  A crude but
> effective fix has been to interpolate by 500, decimate by 499.
> 
> I occasionally notice a similar problem with DVB modules, never with Hermes.
> 
> This has caused me to wonder if some subtle error has crept into OSMOCOM
> or the Funcube module has a timing error (that had been masked
> previously by OSMOCOM). 
> 
> Am I alone in this (in which case I will look closely at usb/audio/pc
> hardware)?
> 
> Thanks in advance,
> 
> Greg
> NZ8R
>  
> Gregory W. Ratcliff
> 
> 
> 
> 
> 
> 
> 
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