is this really a frequency shifter?

jnuaury

http://www.angelfire.com/music2/theanalogcottage/ssbmult.htm

pretty skeptical of this circuit... but looks like ill get some lm1496's in my next parts order to try it out anyways

LektroiD · Posted: Thu Nov 18, 2010 3:19 pm Post subject:

Looks interesting. I have some LM1496's in my stash too. I guess a redraw of the schematic is in order. If you get this finished, let us know what it sounds like (maybe an mp3 demo), and if possible your revised 1496 schematic would be quite handy too.

JAMESveeder · Joined: Nov 16, 2010 Posts: 34 Location: tucson

Yes I'd definitely like to see how this turns out, or read up on some more info about it

blue hell · Posted: Thu Nov 18, 2010 5:19 pm Post subject:

It is a ring modulator of sorts .. but it is claimed to leave only one side band ... as such it would behave like a Bode frequency shifter .. I'm not sure how well it would suppress a sideband though ... it's a lot simpler than an actual Bode frequency shifter .. but then again ... a ring modulator does shift frequencies.

Just to be sure ... this is something different than a pitch shifter .. a pitch shifter will leave harmonic relations as they are, where a frequency shifter does not.

http://acapella.harmony-central.com/archive/forums.html/t-1030019.html has some info.

Dego · Joined: Apr 22, 2008 Posts: 139 Location: Sweden

The paia 4710 Balanced modulator uses a mc1496. Its more than like ringmodulation then... But it is used as a VCA as well.
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blue hell · Posted: Thu Nov 18, 2010 7:16 pm Post subject:

Used as a VCA, yes ... basically ring modulation and VCA is the same thing ... a multiplier .. amplitude modulation, AM. Only thing is that many analog VCAs can use positive modulation voltages only, making it a two quadrant multiplier ... whereas for ring modulation you need four quadrant multiplication (where the amplitude controlling CV can be negative too).

Another difference would be that a VCA usually is used to apply an envelope, that is low frequency modulation, whereas for ring modulation typically audio rate is used ... but nothing stops you to control a VCA at audio rates .. and some simple trigonometry will show the frequency shifting stuff happening then.

jnuaury · Posted: Sat Nov 20, 2010 8:03 am Post subject:

so i just made a parts order a couple days ago and totally forgot to pick up those chips! oops.

im familiar with various ring mods that use this chip, but am really curious to see how this "frequency shifter" will react

im tempted to pull the chip out of my doepfer ringmod to test it out sooner