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Re: [Discuss-gnuradio] Trouble with SSB demod of real signal
From: |
Louis Brown |
Subject: |
Re: [Discuss-gnuradio] Trouble with SSB demod of real signal |
Date: |
Sun, 16 Feb 2014 13:37:05 -0600 |
Tom,
OK I got it fixed after looking at your link. See diagram below:
https://dl.dropboxusercontent.com/u/49570443/test.grc_fixed.png
I was using the Delay block to give me a 65 sample delay to account for the
delay in the Hilbert. This will not work as I assume there is more delay in
the Hilbert than just the 65 taps. The real output of the Hilbert is a
properly delayed version of the input, so I replaced the delay with that. It
now works well What's shown in the diagram is LSB though, not USB.
Thanks,
Lou KD4HSO
On Feb 16, 2014, at 11:19 AM, Tom McDermott <address@hidden> wrote:
> Hi Lou - the diagram you sent isn't going to perform a single-signal
> conversion.
> Taking just the real part of the received signal (and throwing away the
> imaginary part)
> gets rid of information that distinguishes negative frequency components from
> positive frequency components. After that point there is no possibility to
> separate out
> the LSB components from the USB components.
>
> You will need a bit more complicated design, I've used the following
> configuration for
> implementing a phasing type receiver. There are other ways as well, the
> Weaver method,
> and a filter method (using complex taps to a filter).
>
> http://www.tapr.org/~n5eg/index_files/DCC_2013_Gnuradio_Presentation%20-%20Rev%205.pdf
>
> Look at about slide 14.
>
> -- Tom, N5EG
>
>
>
>
>