Ynzn's Multiplexer

by Christiaan Janssen

What's it?

This machine was though to multiplex two signals through a same channel, so they can be demultiplexed and used separately by another machine. This means the possibility of doing real modulations such as frequency modulation, amplitude modulation, phase modulation, ...
Maybe Buzz users won't find it much useful, but I think it can be interesting for machine depelopers.

How does it work?

As the sampling frequency of Buzz is 44Khz, the input signals must be bandlimited to 11Khz. If an input signal has any component over the 11Khz it will be interpreted as part of the other signal and will be demultiplexed as that. This (undesired) effect is called "Alias".
To avoid aliasing I've added a lowpass filter with a cutoff frequency of 11 Khz, that can be turned off I it isn't needed to save CPU. This filter is not very selective so be careful with the input signals you use. Place more filters in the input if you think it is necessary.
You can also choose if you want the input placed in the lower part of the spectrum or the higher. If you choose the lower part the mux does nothing. If you choose the higher part the mux will reverse the spectrum of the input signal, so low frequencies will become high frequencies, and mid frequencies will stay the same. There shouldn't be high frequencies in the input (as explained above).
The demultiplexer will have to filter the input signal and reverse the spectrum of the high-freq part of the signal.

Usage

P a r a m e t e r s

Notes

If it were possible to make Buzz work at 96Khz there would be no band limits. The limit would move to 24 Khz. That is no limit for an audio signal.
To show its use it comes with another machine (the amplitude modulator) and a demosong.