## CRC field in the middle of a packet

Is it possible (and reasonable) to insert a 32-bit field in the "middle" of a packet, such that the overall CRC-32 of the packet is zero? I know how to put CRC fields...

## BCH for GF(4)

I've been working with binary BCH codes (63,39) and (63,45) for several weeks, where an additional even parity bit is added to the data to create a 64-bit codeword,...

## Receive IF Freq Selection for a Full-Duplex Transceiver

Hello,In a full duplex RF transceiver, what are the potential problems of a receive IF strip at a frequency that's equal to the separation between the transmit...

## Re: One raised cosine filter vs two cascaded root raised cosine filters

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...

## Re: One raised cosine filter vs two cascaded root raised cosine filters

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...

## Re: One raised cosine filter vs two cascaded root raised cosine filters

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...

## Re: One raised cosine filter vs two cascaded root raised cosine filters

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...

## One raised cosine filter vs two cascaded root raised cosine filters

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

True.  Good point.

## Re: Root Raised Cosine Filter

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

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

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

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

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

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

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

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

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

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...

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