Thread: FM "deviation"
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Old 29th Mar 2010, 3:11 pm   #22
G8HQP Dave
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Join Date: Sep 2008
Location: Solihull, West Midlands, UK.
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Default Re: FM "deviation"

If you don't use filters then you would have to use something like a phasing sideband receiver, but again this introduces phase shifts where you really want none. To do this you need an accurate 90 degrees over 23-53kHz, or equivalently P and P+90 in two paths, combined with an accurate P over 0-15kHz. I guess the Japs were smart enough to do this, but what about component ageing? You gain a little signal-to-noise, but potentially lose stereo separation and image clarity. My guess is that it might measure well and could have impressive advertising, but sound awful with instruments moving around for different notes. Not like other 1980's hi-fi then!
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