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Need for a signal generator

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I have an old, analogue tone generator which produces a tone at a certain frequency and a certain amplitude. When I am running tests I can see what's happening in one frequency but not in conjunction with others.

For the projects I am experimenting with I would want it to create more than one frequencies (maybe up to 12) at a separate amplitude each, so I'd be looking for 12 separate knobs for amplitude control and 12 separate knobs for frequency. Of course if it were digital you'd have "multifunction" buttons.

An additional feature would be the ability to vary the *amplitude* on each channel by a certain amount, % wise, like in AM transmission,  based on a random generator or based on a modulating frequency.

An other additional feature would be to vary the *frequency* on each channel around the centre frequency by a certain %, like in FM transmission, based on a random generator or based on an amplitude waveform.
Eg I could say :

 channel 1: base F=100Hz, A=1V pk, sine
 channel 2: base F=1KHz, A=0.1V pk, sine, FM mod: 5%, random generator.
 channel 3: base F=5KHz, A=1V pk, sine, AM mod: 10%, random generator.

Does such a tool already exist?

You don't say if you want separate channels or separate tones on the same channel.

You don't say anything about budget.

Cheaper signal/function/arb generators are generally one or two channel. There are multi-channel instruments available but they are very expensive and designed for much higher frequencies generally than you need.

The Rigol DG4062 has a harmonic function so you can set the harmonics separately on the same channel. It also has two channels. I don't own one so have never used this feature.
It would also be less simple than the analog arrangements of buttons that you envisage.

Here is a paper published on using a graphics card for multi-channel output, each colour channel is used as a separate output and by using multi-monitor cards it is possible to get a lot of channels very cheaply.

Another thought is to use pc sound cards.


--- Quote ---Another thought is to use pc sound cards.
--- End quote ---

I was also going to suggest this - along with a decent audio editing program.

Yes, should be easy to do on a pc.

A quick search turned up this:
I have not downloaded or tested it but maybe it is useful:

 - Sound generator supports frequencies from 1Hz to 22kHz
 - Simultaneous tone generation of up to 16 tones at once

Otherwise it wouldn't be too difficult to program it yourself.

Should have thought about the PC and its sound chips - but I was thinking of a bech top instrument to replace my current signal generator. I suppose one of those 200 UK pounds tiny laptops could be used and it could do much more than that - up to 20KHz.


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