ACE, low frequency perfect square signal

[abique]

Hi, do you know how to make a low frequency perfect square signal with ACE?
I need it to make some modulations.

By perfect I mean only two possible values: 0 and 1.

Thanks.

[Urs]

It may sound paradox, but in the digital domain a perfect square is pretty much never just 0 and 1. Explained by the sampling theorem, even a perfect square sampled from an analogue synth looks "jaggy" at the edges. It has to be.

[abique]

And is it possible to have a rand hi-low modulation source in ACE like in Diva's LFO? Thanks.

[Sendy]

I think, but I could be wrong, a perfect square wave is not only impossible in digital domain but also in the Universe, since for an instantaneous rise or fall time an object would have to move a certain distance instantly, and then come to a stop in that same instant, requiring infinite energy.

I like to think that if there is a heaven, it would be more friendly to infinities and it'd be possible to produce and hear a waveform with infinite harmonics. (Check out Rudy Rucker's novel White Light for a good description of what such an afterlife might be like, it's a fun book!).

[abique]

The limitations of the universe are not my problem . I would like to use very close to perfect square signal for modulation purpose.

By the way, perfect square signals exists: f(t) = ((int)t) % 2;

[xh3rv]

I think, but I could be wrong, a perfect square wave is not only impossible in digital domain but also in the Universe, since for an instantaneous rise or fall time an object would have to move a certain distance instantly, and then come to a stop in that same instant, requiring infinite energy.

Interestingly the mathematical definition for the Dirac delta - used in place of "y = infinity when x = 0, 0 all else" - means something more nuanced in respect to integration. It's a 'rapidly decreasing' distribution that integrates to the value 1 ... something like a probability curve squeezed into a spike that we know isn't exactly a spike but looks that way no matter how closely we zoom in. Truly a strange and wonderful bit of mathematics.

Got this from a fantastic and completely rigorous (well, all the hand-waving is explicitly stated) series from Stanford:
http://see.stanford.edu/see/courseinfo. ... f45c0ee091

[pdxindy]

Hi, do you know how to make a low frequency perfect square signal with ACE?
I need it to make some modulations.

By perfect I mean only two possible values: 0 and 1.

Thanks.

no can do...

[Biscotto]

That's when a pencil and a piece of paper beats the universe!

[trance_lucent]

The limitations of the universe are not my problem . I would like to use very close to perfect square signal for modulation purpose.
By the way, perfect square signals exists: f(t) = ((int)t) % 2;

Both Urs and you are speaking about different things. Urs means perfect harmonic square which is good to act as harmonic oscillator. And you are speaking about modulation. Any modulation isn't harmonic process. Even slow amplitude modulation generates inharmonic content. And, for some extent, any possible signal is appropriate for modulation, even inharmonic, such as your binary square. Sometimes for some types of modulation naive square is more appropriate. But if you want musical modulation (FM, AM, PM) you need harmonic modulator aswell. Although as you are speaking about low frequency modulation, I think it isn't this case. But such square isn't appropriae even for gating effect. What modulation type do you want?

[pdxindy]

Hi, do you know how to make a low frequency perfect square signal with ACE?
I need it to make some modulations.

By perfect I mean only two possible values: 0 and 1.

Thanks.

Sorry about the earlier post... I missed that it was for modulation...

Use the Mapper as the modulation source. Set it to 2 steps. Put one step at 0 and the second step at 100

Then set mode to Map Quantize and mapping source to Ramp. Now the Down parameter on the Ramp envelope will control the speed and the Hold and Rest parameters control the duration of steps 1 and 2 respectively (pulse width).

[abique]

What modulation type do you want?

I want it to do modulate the pitch of a sin signal then put a small delay behind the sin and here comes R2D2.

[trance_lucent]

What modulation type do you want?

I want it to do modulate the pitch of a sin signal then put a small delay behind the sin and here comes R2D2.

I think just binary square isn't good for this - it will result in wide spectral bursts in time of square switching between 0 and 1. Although bandlimited square isn't appropriate too, if you don't need pitch overshooting and ripples. So you better get your binary square (the way as pdxindy suggested?) and to filter it with lowpass. Or Ace has Lag generators as Bazille?

[abique]

Use the Mapper as the modulation source. Set it to 2 steps. Put one step at 0 and the second step at 100

Then set mode to Map Quantize and mapping source to Ramp. Now the Down parameter on the Ramp envelope will control the speed and the Hold and Rest parameters control the duration of steps 1 and 2 respectively (pulse width).

Thanks! I did not know that I could use the mapper like this, it is great great great!
But the square signal is the same as the one from the oscillator.
Anyway I can use it for almost random square hi-low, and the result is good.

Thanks everybody

[pdxindy]

Use the Mapper as the modulation source. Set it to 2 steps. Put one step at 0 and the second step at 100

Then set mode to Map Quantize and mapping source to Ramp. Now the Down parameter on the Ramp envelope will control the speed and the Hold and Rest parameters control the duration of steps 1 and 2 respectively (pulse width).

Thanks! I did not know that I could use the mapper like this, it is great great great!
But the square signal is the same as the one from the oscillator.
Anyway I can use it for almost random square hi-low, and the result is good.

Thanks everybody

And of course you can use more than 2 steps to create all sorts of complex shapes

[Sendy]

The limitations of the universe are not my problem . I would like to use very close to perfect square signal for modulation purpose.

By the way, perfect square signals exists: f(t) = ((int)t) % 2;

I realize it wasn't relevant to your problem, so much as an interesting aside. Or just any excuse to talk about squarewaves tearing up spacetime

I will say, though, I use squares a lot for modulation of pitch, filter, etc, both at audio and LFO rates, and I've never had a problem with the waveshape. For all intents and purposes, it appears a "naiive" square to the senses, even though under the micro(scillo)scope, it's not.