emphasis coefficients

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 \(r&#4294967295;p. sans -no-sp-am\)" <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