Pc based function generator

[d3imlay]

I turned on my old HP today and the negative half cycle (sine wave) is clipped as though there is some DC offset. I don't have time to repair it and would like to get something software based.

Is anybody using a computer for a function generator?

[dfdye]

There are a bunch of free ones out there, but if you just need a sine wave, I think TrueRTA will probably do the trick for you. The problem with PC based solutions is that they are limited by the resolution of your sound card. If you can live with that, then this may do the trick.

There are others out there, but this is the first one that popped into my head.

David

PS Are you sure there is not a simple offset correction on your function generator? This sounds like a setting issue more than something actually being broken. . . .

[d3imlay]

Originally posted by dfdye

PS Are you sure there is not a simple offset correction on your function generator? This sounds like a setting issue more than something actually being broken. . . .

The negative half cycle is clipped at all levels so it's happening before the attenuator. I may have to tear into it and fix it.

As far as the pc based generator goes, I want a sweep generator to do some testing of an output relay circuit. I also want to do some one shot pulse testing.

[Panelhead]

There are some other generators that connect to your pc. The sound card based generators are limited. I was thinking of going this route, but buying a 200.00 24 bit, 192K sound card to use a free function generator program convinced my to buy something designed to do this.
Ended up with a combination scope, generator, and fft. Cost was more than a nice soundcard, but is much faster. Nice thing also is it is small and two channel. Makes hauling it around a moot point.
I was visiting a friend who works in a military lab. He brought home a new 4,000.00 portable scope with genertor built in. It looked like close to identical qualilty, my generator into his scope, or his generator into my scope and fft. His was a little easier to diddle with since it ran real time and was not a DSO.
Mine was made by CL Systems. Now that I have it, see others that I wished I had instead
. This is a niche market, lots of great used full sized equipment out there. If you have the room for a bench of equipment.

George

[jackinnj]

If you can play with C it looks as though "Nuts N Volts" magazine is beginning a series of articles on writing DSP code with freeware libraries.

[Zero Cool]

I have used a Audigy2 card and Soundforge to make a basic function generator. I was trying to duplicate some burst testing and that setup worked well.

With sound forge i could only do sine waves really but i could set up short burst of tone and at various levels etc.

I think you can do sine, square, saw, triangle, noise etc with the old soundforge 4.5 (still the best i think). However creating a square wave onscreen and getting real square wave out of a sound card is another story. Plus you may or may not get other artifacts as well.

Plus you have a limited output level available requiring some sort of amplifier if you need more then a few mv and that can then add more junk etc etc.

Good, older, Sig gens are available cheap. I picked up a nice Kron Hite function generator for $20.00 and it works great.

Zc