On Fri, May 28, 2010 at 05:37:47PM +0200, [email protected] wrote: > On Fri, May 28, 2010 at 08:30:54AM -0700, Niels Mayer wrote: > > > Audio ADCs and DACs have three important inputs; > > the signal input, the voltage reference, and the clock. > > Noise and interference on the voltage reference causes > > amplitude modulation, and jitter on the clock causes > > phase modulation. The resulting modulation products > > look very similar in the frequency domain. One of the > > authors once spent several days trying to track down a > > low-frequency jitter problem, only to find that it was > > in fact a problem of LF noise on the voltage reference. > > You're close. See the extra hint in a previous post.
is that an USB card ? there is a "small" peak at 1000Hz which looks like a usb power drain at isochronous packet frequency. maybe its the packets voltage lifting the local ground a bit. > > Ciao, > > -- > FA > > O tu, che porte, correndo si ? > E guerra e morte ! > _______________________________________________ > Linux-audio-dev mailing list > [email protected] > http://lists.linuxaudio.org/listinfo/linux-audio-dev -- torben Hohn _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
