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From: | Johnathan Corgan |
Subject: | Re: [Discuss-gnuradio] SSB demodulation |
Date: | Wed, 08 Sep 2004 07:50:45 -0700 |
User-agent: | Mozilla Thunderbird 0.7.3 (Windows/20040803) |
cswiger wrote:
Hi All - I'm making wild stabs are writing modules to demod SSB with REAL+IMAG or REAL-IMAG for upper and lower sideband, simply by cloning David Carr's gr_complex_mag module:
You have to phase delay the IMAG (Q) symbol stream by 90 degrees (Hilbert transform all-pass filter) prior to the addition or subtraction with the REAL (I) symbol stream. (And don't forget to keep them in time sync; that is, whatever the sample propagation delay through the Hilbert filter is for the Q stream must be accounted for in the I stream prior to addition or subtraction.)
This is the "phasing" method of SSB modulation/demodulation, Google has many references.
73 de Johnathan, AE6HO
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