No profile info found for jonmcleod2003

Neil, this is the Scilab script I hacked up from your script above.  Thanks!// //eyeplot.m 10/29/19 Neil Robertson // Plot eye diagram of vector x // fs = samples...
This was very informative.  Thanks!Playing around with RC and RRC filters, I have found two things: First, I am not using enough taps for this application, and...
There is just something I don't understand here.  I have an raised cosine filter with 31 taps, and a root raised cosine filter with 31 taps.  If I send a single...
I think I have a fundamental misunderstanding, because the first rrc filter interpolates while the second does not. Every time I input a symbol impulse followed...
If I send a random series of symbol impulses (+3.0, +1.0, -1.0, -3.0) through a raised cosine filter (alpha = 0.2, 31 taps), the output contains a filtered, delayed...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/18/2020)
True.  Good point.

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/18/2020)
In this case, it's because the DMR spec "splits" the RC filter between the transmitter and receiver. The transmitter splatter filter is RRC and the receiver noise...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/18/2020)
It seems like, as a practical matter, to "split" a RC baseband filter into a transmit RRC filter and receive RRC filter, your system has to work like this:The transmitter...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/18/2020)
napierm, kaz,As a basic sanity check, is one raised cosine filter equal to two cascaded root raised cosine filters, assuming alpha and filter length match (the sample...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/18/2020)
You are right, and I was deeply confused about how this works. This weekend, I started giving the filter one symbol value followed by 9 zeros, and my various RC...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/15/2020)
One real conceptual problem I'm having, is that RC or RRC filters seem to cause intersymbol interference straight out of the chute.When I play around with RRC or...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/14/2020)
In this case they'll be scaled and fed by I2S to the direct modulation system on an LMX2571, which is on existing hardware.  So we don't need to upsample it further...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/14/2020)
Thanks! I've thought about GFSK or other modulations, and completely different ways to do it, and we might go another direction soon. But for right now, for a number...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/14/2020)
I'm weak here, but I think what I'm doing is not quite the same as interpolation. I'm building in code a baseband signal, which is a train of symbols, each 10 samples...

Re: Root Raised Cosine Filter

Reply posted 2 weeks ago (05/14/2020)
I pass fixed point values +3, +1,-1,-3 into the filter, which correspond to dibit values 01, 00, 10, 11 from the data stream. Each symbol includes 10 samples, so...

Root Raised Cosine Filter

New thread started 2 weeks ago
Hello.I am experimenting with a soft transmitter and receiver, using DMR modulation.My plans is this. On the transmit side, I generate dibits, filter them with an...

Use this form to contact jonmcleod2003

Before you can contact a member of the *Related Sites:

  • You must be logged in (register here)
  • You must confirm you email address