Reception quality dependent on Soundcard

[drm-fuzzy]

Hi all,

I have a soundcard Terratec DMX-Fire 1024. Using this soundcard I have a strong fading effect of the input signal quality resulting in getting completely out of sync and resyncing every 15 seconds.
Using a cheap old Creative Soundcard did not show this effect.
Somewhere on the net I found a remark that the sampling frequency of the Soundcards is very often not sufficiently precise which leads to decoding Problems.

Has anyone made similar experiences or has someone a solution to this Problem.
My ideas:
One possiblity would be trimming the Xtal frequency of the Soundcard.
Maybe replacing the XTal of the Soundcard could help?

Has someone an idea about the required precision of the sampling frequency?

Regards

Werner

[dk8cb]

Somewhere on the net I found a remark that the sampling frequency of the Soundcards is very often not sufficiently precise which leads to decoding Problems.

Dream's evaluation window displays the sampling rate offset, see screenshot. This number should be fairly stable after the PC has reached its temperature equilibrium. If the value shown changes a lot, then something will be wrong.
Some soundcards produce other problems because they resample internally or drop bits somehow.

Roland

[drm-fuzzy]

The sample Frequency offset is constant at -55ppm, however the DC frequnecy of the DRM signal fades a lot- At first glance I thought the reason might be an unstable receiver (local oscillator) but after trying another soundcard which worked correctly I assume that it is a soundcard issue.

regards
Werner