MATRIXSYNTH: Thomas Henry Voltage Controlled Quadrature Function Generator


Monday, June 18, 2007

Thomas Henry Voltage Controlled Quadrature Function Generator

Title link takes you there.
Some snips:
"To have a quadrature waveform, you really need at least two waves. The first wave could be said to be at 0 degrees, and the second wave could be said to be in quadrature with that wave - in other words, the quadrature waveform is 90 degrees out of phase to the zero degree waveform. The frequency of both waves is the same - it's the offset in phase between the two waves that defines the function.

Figure 1 [top two] illustrates this offset - notice how the lower triangle waveform crosses the center line 90 degrees "behind" the upper triangle wave.

It's easy enough to get two waves at the same frequency and one hundred eighty degrees out of phase - that only requires simple inversion - the 180 degree waveform is merely the exact opposite of the 0 degree waveform. But, to get an offset of 90 degrees, well, that takes some doing....

Applications for the VCQFG
Thomas' mention of the use of the VCQFG with his SuperSeque design above is just one of a plethora of applications. Consider that, with this module, you have access to four triangle waveforms that are at the same frequency, but have rise and fall segments offset symetrically over time."

12 comments:

  1. The Tabernacle says:

    "Caution: You are approaching the periphery shield of Vortex Four."

    ReplyDelete
  2. polyfusion had that feature, results can be amazing, really a nice one ...

    ReplyDelete
  3. or quad panning, nice ;)

    ReplyDelete
  4. The Zerocillator also has quadrature out.

    ReplyDelete
  5. i love quadraphonics. if only it was the standard instead of stereo. i can think of some cool ways to use this device for that application.

    ReplyDelete
  6. Serge has a dedicated Quadrature Oscillator and the internal carrier version of their Frequency Shifter has quadrature outputs.

    ReplyDelete
  7. Not sure if anyone would be interested in this... I built a 10-band equalizer in Csound where each band is panned individually, using phase offset lfos similar to the quadrature function generator.

    Here's the snippet of code that creates the phase offset lfos:

    klfo1 table ( klfo + 0.0 ) * ilength, iwave, 0, 0, 1
    klfo2 table ( klfo + 0.1 ) * ilength, iwave, 0, 0, 1
    klfo3 table ( klfo + 0.2 ) * ilength, iwave, 0, 0, 1
    ...
    klfoA table ( klfo + 0.9 ) * ilength, iwave, 0, 0, 1

    The floating point numbers set the phase for each lfo. Phase is normalized to a range of 0 to 1, so a value of 0.1 equals 36 degrees and 0.5 equals 180 degrees.

    The full code can be found here, in instr 112.

    I also happen to want a zeroscillator really, really badly.

    ReplyDelete
  8. Cwejman makes a module in Eurorack called the PH-4 that has the 4 outputs in the same configuration. Very fun!

    ReplyDelete
  9. Thumbuki, that's pretty cool. If you have a post for it, post a link here and I'll put up a new post.

    ReplyDelete
  10. thumbuki: keep the csound coming!

    ReplyDelete

To reduce spam, comments for posts older than one week are not displayed until approved, usually same day. Do not insult people. For items for sale, do not ask if it is still available. Check the auction link and search for the item. Auctions are from various sellers and expire over time. Posts remain for the pics and historical purposes. This site is meant to be a daily snapshot of some of what was out there in the world of synths.

PREVIOUS PAGE NEXT PAGE HOME


Patch n Tweak
Switched On Make Synthesizer Evolution Vintage Synthesizers Creating Sound Fundlementals of Synthesizer Programming Kraftwerk

© Matrixsynth - All posts are presented here for informative, historical and educative purposes as applicable within fair use.
MATRIXSYNTH is supported by affiliate links that use cookies to track clickthroughs and sales. See the privacy policy for details.
MATRIXSYNTH - EVERYTHING SYNTH