Re: [Discuss-gnuradio] Any implementation of Spread Spectrum

[Mir M. Ali]

Hi Johnathan,
Is your code public yet?

On Fri, Jul 17, 2009 at 12:57 AM, Mir M. Ali <address@hidden> wrote:

Thanks, I will try this out.

On Thu, Jul 16, 2009 at 11:34 AM, Colby Boyer <address@hidden> wrote:

In regards to 1.

From what I have experienced, you can multiply the received signal by the up sampled PN sequence and still get a good correlation.

However I do not know if the sequence becomes less orthorgonal when you this(worse auto-correlation).

On Wed, Jul 15, 2009 at 9:27 AM, Mir M. Ali <address@hidden> wrote:

Hi Johnathan,
I have a few question regarding implementation. The book that you referred earlier was of great help. Thanks.
I am sure this won't take a lot of your time and I would be really glad and thankful to you if you answer them.

 In the transmitter the data and the PN code is ex-or and then modulated and transmitted. So basically this is a BPSK transmission. At the receiver the received signal is first multiplied by the PN code in order to strip it free of PN code and this happens at the E/P/L correlation and Costas Loop block. Being a BPSK signal this is correct.

1. My question is can I just use the upsampler and multiply the upsampled sequence with the received signal samples?
2. Where will the AGC and the RRC filter go in this arrangement?

Any help would be appreciated.
Thanks.
Ali

On Tue, Feb 24, 2009 at 11:23 AM, Johnathan Corgan <address@hidden> wrote:

On Mon, Feb 23, 2009 at 8:25 PM, Mir Ali <address@hidden> wrote:

> can you suggest me a place where I can find more information about the phase
> sync and the freq sync methods you used in your work. It will be of great
> help to me.

There is plenty of information available via Google.  An excellent
reference book is:

"Fundamentals of Global Positioning System Receivers: A Software Approach"
Wiley Series in Microwave and Optical Engineering
James Bao-Yen Tsui, 2004

Johnathan

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