2/4 quadrant multiplier theory
jorgen.bergfors at idg.se
jorgen.bergfors at idg.se
Thu Sep 3 10:20:18 CEST 1998
Yes, you can make a four quadrant multiplier with two OTAs that are connected
much the way you describe. See Barry Klein's book. Actually you can make a four
quadrant multiplier vith just one OTA, but don't ask me to explain the theory
behind this. A circuit for this is in Barry Klein's book too.
/Jorgen
MIME:moylan at eden.rutgers.edu on 98-09-02 20.06.36
To: synth-diy at mailhost.bpa.nl @ SMTP
cc: (bcc: Jorgen Bergfors/IDGSE)
Subject: 2/4 quadrant multiplier theory
Okay, just sitting here thinking about something.
A 2 quadrant multiplier is essentially a VCA right?
And a 4 quadrant works similarly except that if the
control signal goes negative the polarity of the
signal is reversed (with respect to + control signals).
Would it be possible to get similar results by using
a Voltage Controlled Mixer mixing 2 signals 180 degrees
out of phase. Assuming a certain bias added to the
"control" signal, at 0 input we'd have 0 output (equal
mix of signal and inverted signal), if the control
swings positive, we get more straight signal, if it
swings negative, we get more inverted signal. Am I
missing anything? Thanks. dave moylan
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