looking for a signal generator

[Ahmad_tbp]

hi all ,
i m looking for a simple sine wave generator w freq range control ( around 40 to 150 hz ) a pulse function w control ( around .1 sec to 5 sec ) ... any idea ?

 

[anatech]

Hi Ahmad_tbp,
Try to find an old B&K 3020 or similar. It's not the cleanest sinewave, but you are looking for a function generator.

If you need a better sine wave, any oscillator will work, build a gate controller by another circuit (555 timer) for your burst controller.

-Chris

 

[Ahmad_tbp]

hi anatech , and thanx for reply
i never worked with a generator before or never build one , i know nothing bout them , i wanna build one ( as u said a function generatr ) for a friend of mine , so do u have any schematic , article or any thing that can help me plz ? 🙂

 

[SY]

Do you have a sound card on your computer? If so, you've got yourself a sine wave generator.

 

[anatech]

Hi SY,
Standard warnings about grounds and output circuit protection apply! 😉

-Chris

 

[Ahmad_tbp]

hi sy , yeah i have a sound card !!! ( one of the best old ones!! ) , and already have a very usefull tone generator software with all i need , as i said ,one friends of mine saw this software and ask me if i can build a circuit , doin like this software , so i wanna build him one ! lol 😀
i found this circuit : http://www.electronickits.com/kit/complete/meas/ck102.pdf
, how is it ? and how can i change the freq in this circuit ?
and one thing else , any idea how to give this circuit a pulse generator control ???

 

[anatech]

Hi Ahmad_tbp,
The resistor, R5 varies the frequency. Your output sine wave will be poor with that circuit.

Why not use the XR2206 there are many links for it, as well as the data sheet. Or you can use the XR8038 that does the same thing. It's all in a chip for you and better than was the link you posted will give in performance.

-Chris

 

[jackinnj]

Do you have a sound card on your computer? If so, you've got yourself a sine wave generator.

TureAudio's freeware version will give you a sine-wave generator.

In fact, if you have access to some opamps and a '555 timer (NE555 or LM555) you can make a pulse generator or sinewave generator. Search "NE555 Circuits" or "555 Circuits Mims" on google.

To get a good sinewave out of an NE555 you have to take a pair of opamps and configure as a 4th order low-pass filter after the output pin (3) of the NE555.

 

[anatech]

Hi jackinnj,
The only problem with that approach I can see is that it has to be a tracking filter for variable frequencies out. Output level instability may result.

A tuneable wien bridge may work, but the one chip wonders seem to address the problem directly. You can gate the output on and off with a 555 type squarewave oscillator. This statisfies all the requirements.

-Chris

 

[SY]

Dazyweb is back, too. Their sig generator software is very versatile.

 

[pinkmouse]

I built one with the MAX038 chip on perfboard, very straightforward.

 

[anatech]

Hi Al,
That is a second sourced 8038, isn't it? I agree they go together easily.

-Chris

SY,
Ahmad_tbp wanted to build a stand alone for a friend I think as well.

and already have a very usefull tone generator software with all i need , as i said ,one friends of mine saw this software and ask me if i can build a circuit , doin like this software , so i wanna build him one ! lol

From post #6. It appears also that Ahmad_tbp already does this, I guess??

-Chris

 

[chrispenycate]

I dislike that circuit. Not only is it a lousy triangle to sine converter, it's single rail with no blocking capacitors, which means all the waveforms will have a massive DC offset. Even with a battery, it would be so easy to avoid this.
A comparator (ordinary op amp with no feedback) between the triangle output and a voltage set by a pot would give a variable mark space ratio pulse, and you could probably get sawteeth out of it with a little effort, but all 0 to+ve voltage, no ± 1volt.
Oh, I do have all the circuits on hand, if ever, but no ready-made PCB; I'd have to build one on veroboard (and probably add a pink noise source for luck)

 

[moamps]

That is a second sourced 8038, isn't it? I agree they go together easily.

IC MAX038 is, IMO, completely different from 8038. IC MAX038 is a relatively new function-generator chip which can generate frequencies up to 20MHz.

Regards,
Milan

 

[pinkmouse]

Yes, it's a very nice stable source. I really must get around to rebuilding the output buffer that has a slight ring on square waves, but it's just too useful to take apart! 🙂

 

[Ahmad_tbp]

hi all , thx for replies
i ll never find a XR2206 here ! lol 😛
and if i wanna be honest , i couldn t understand anything of ur posts 😛 ,
as i said i m so virgin in tone generator , and lookin for a simple circuit of sinewave generator a pulse function 🙁 .... any idea ? any link ? 🙁

 

[anatech]

Thank you,
I must try one of these things. I was lead to believe they were another 8038 device.

Now I'll grab the datasheet.

-Chris

 

[anatech]

Hi Ahmad_tbp,
I left you some google search pages a few posts back, some that linked to the data sheet on each device.

Here is a similar link to the MAX038 and the data sheet is here .
After this is no longer available, one might ask, Where have all the cool chips gone?

-Chris

 

[moamps]

...I really must get around to rebuilding the output buffer...

If I remember correctly, there was a project with MAX038 published a while back in a German magazine, ELV I think. The output (disrete) buffer used in the project was quite something and if you're interested I may be able to dig it up for you.

Ahmad:

You can order sample IC MAX038 on the manufacturer's site (Maxim). There you can also find application notes and other useful info about the chip.

Regards,
Milan

EDIT: Ooops, last time I visited the site it was still alive.

 

[anatech]

Hi Milan,
That chip is no longer recommended for new design. There may not be any samples available. Too bad, because I was about to order one. I hope Digikey or Newark still have a few.

-Chris