Does anyone have any experience of designing an SSB modulator using Weaver's Method (AKA The Third Method). I have some thoughts on it that I would like to bounce off someone with a better knowlede of it than I have.
-- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
The sideband folding thing? Never tried it--I'm not a ham and haven't worked in RF voice communications in almost forty years (1981-83, good times).
I did do a phasing-method SSB receiver long ago, using a LMF100 switched-cap filter as the low-frequency Hilbert transformer, which worked great. It was for a laser inteferometer detector for aerosol particles. Interferometers are amplitude-sensitive, so the required dynamic range is the square root of what you'd need in an intensity-sensitive system. That meant that a noisy SC filter was no problem, and the SSB detection got me a 3-dB SNR improvement, equivalent to doubling the laser power.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
You should ask in detail here, but also in SDR forums.
It's normal for SDR systems to digitise I and Q and do the weaver thing in software, so there are folk who know about that.
Clifford Heath
I was looking at analogue methods (sorry, I should have said that at the outset).
-- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk
You may have good luck searching amateur radio sites, forums and blogs. From my limited knowledge a bugbear is the matching in amplitude and phase response needed for the two pilot-tone filters. There is also that weird notch in the passband around the pilot tone that speech doesn't much notice but is hardly suitable for hi-fi!
piglet
Yes, but addition is addition whether it's analog or digital.
CH
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