News:

Welcome to the AlpineSoft support forum.  To return to the main website, click here: www.alpinesoft.co.uk

Main Menu

DSD to PCM Conversion - roll off filter

Started by dtc, November 07, 2014, 10:46:26 PM

Previous topic - Next topic

dtc

I am converting from 5.6 MHz DSD to 192K PCM. In some software there are options to apply optional roll off filters to remove high frequency noise.  Does VS apply such a filter? If so, what are its characteristics? Does it vary by PCM output sampling rate?

Thanks.

Tom

Paul Sanders (AlpineSoft)

Hi,

It rolls off at 48 kHz for DSD standard rate and 96 kHz for DSD double rate.  Any higher and you get a lot of noise in the converted signal.

dtc

So basically at the Nyquist frequency for the sample rate,  If I am going form2xDSD to 192K sample rate, it starts rolling off at 96 KHz.    What is the roll off rate, just for curiosity.

Paul Sanders (AlpineSoft)

It's pretty steep.  I'm not sure exactly what it equates to but we use a 96 pole FIR filter which was designed to have a reasonably sharp cutoff with good rejection above the cutoff frequency.

dtc

Thanks. Clearly I am not going to hear anything above that :)