discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] (no subject)


From: Eric Blossom
Subject: Re: [Discuss-gnuradio] (no subject)
Date: Thu, 1 Dec 2005 14:08:45 -0800
User-agent: Mutt/1.5.6i

On Thu, Dec 01, 2005 at 01:53:15PM -0500, address@hidden wrote:
> On Wed, 30 Nov 2005 15:00:34 -0800, Eric Blossom wrote:
> > The calling sequence for the gaussian filter design changed.
> > Even if ggmsk-test were fixed to use it, it doesn't work anywhere
> > nearly as good as the new code.
> 
> I would like to use the new code in gmsk2 but I can't implement the CRC32
> and the whiten/dewhiten in the microprocessor used in the transmitter.  The
> original engineer on this project, who left the company and that I am
> replacing, selected a real poor microprocessor.

Then use CRC16.  It only requires a constant 256 byte table.
The table required for whitening only needs to be as long as your
longest message.  Shouldn't be a problem, even on a 8051.

What processor *did* he choose?  ;)

> Do you think that I can use the same basic idea of the gmsk2 framer and
> sync whithout the use of the CRC32 and whiten?

Without whitening you may get no transitions in the data (e.g., all
zeros or all ones).  This results in a single tone which has zero
information for recovering the clock.  Whitening is cheap.  I assume
you've got some flash to store code and/or data.

Eric




reply via email to

[Prev in Thread] Current Thread [Next in Thread]