On Feb 20, 4:38*pm, Bob <sten...@yahoo.com> wrote:
> On 20 Feb, 20:41, Mark <makol...@yahoo.com> wrote:
>
>
>
>
>
> > > So now I see something,,,notice the small peak to the left of the
> > > cursor on the second and fourth traces. Should this not be the same as
> > > the peaks beside it?
>
> > remember you are looking at the RRC filter..which is only 1/2 the
> > picture
>
> > pass this output though another RRC filter so that you have the full
> > RC filter and you will see what the receiver sees...
>
> > the Rx and Tx have matched filters and the NYquist filter is both of
> > them in cascade,
>
> > you are looking 1/2 way through the cascade..
>
> > Mark
>
> Hi Mark,
>
> The pulses you see on the first link is what happens when I pass the
> data through the RRC on the TX link. On the demod side links 2 and 3
> are when the data from the modulator is passed through idential RRCs.
> So, in effect I already have the RC response at the receiver. But is
> it correct...that's what I would like to know?
>
> Bob- Hide quoted text -
>
> - Show quoted text -

Hello Bob,

The feeding of pulses into the RRC filter (via convolution) assumes
your pulses become Kronecker deltas. Don't feed rectangular pulses,
instead feed spikes into the RRC filter. Then after going through two
of these in sucession, you will see a nice looking signal. You are
currenly getting a bunch of ringing resulting from the rectangular
pulse's response comingled (convolved) with the RRC's response. For
simplifying the testing, just try an RC filter and look at its output.
Two RRCs convolved is an RC. Try it!

IHTH,

Clay