Forums

emphasis coefficients

Started by Unknown December 27, 2003
Hi all !

I am looking for the coefficients for a FIR filter to compute the
pre-deemphasis 50/15 us. Does anybody know them ?

Are there any IC that can do it without having to use a DSP ?

Thanks in advance !

Sam


"Sam \(r&#2013265929;p. sans -no-sp-am\)" <totalsam-no-sp-am@hotmail.com> wrote in message news:<3fede164$0$736$5402220f@news.sunrise.ch>...
> Hi all ! > > I am looking for the coefficients for a FIR filter to compute the > pre-deemphasis 50/15 us. Does anybody know them ? > > Are there any IC that can do it without having to use a DSP ? > > Thanks in advance ! > > Sam
You don't want to use FIR. The original standards are based on analog filters, so you should use IIR. This will give flat amplitude/phase for the whole system (if the pre-emph is linear-phase and the de-emph is analog or IIR, the composite phase response will not be flat) Since its a single pole-zero system, you can manually wiggle the 2 coefficients to fit the analog design and get pretty close pretty fast. It will never match the analog system perfectly, but you can get "close enough". Bob Adams