my next little project

[stickpin]

Frequency/function generator with sine, triangle, square wave. Adjustable frequency (upto at least 100khz 1mhz would be good) and adjustable amplitude.
I want a frequency readout, LCD or 7 seg display.

Think thats everything, anything else is bonous.

So im sure someone on here has done a similar project? im trying to decide what components to use, all op amps? all in one IC package?

Basically im just looking for ideas/suggestions/opinions. I have only thought about it up to now so anything at all from you lot would be good.

The only thing i can see me having problems with is the frequency read out! im not that advanced with programming yet.

 

[HarveyH42]

Search the internet, there are a bunch of function generator projects. I've been thinking about doing a DDS with an AVR microcontroller, but think it only goes up to 25kHz. I saw a huge variety, while searching. There are several chips that you can set the frequency digitally, don't remember the range, or if the amplitude was adjustable digitally on chip.

 

[RadioRon]

This is a good project. I built one years ago and still use it today, except that I never put the LED display on it.

I like the ICL8038 IC from Intersil. The Maxim Max038 looks interesting since it has a much higher frequency range. For frequency readout, I like the idea of using one of the many AVR or PIC development boards with an added 2 line LCD display and code this to count frequency and maybe to control the generator too.

 

[Nigel Goodwin]

I like the ICL8038 IC from Intersil. The Maxim Max038 looks interesting since it has a much higher frequency range.

But have all been obselete for years now.

 

[stickpin]

yeh ive just been looking at the max038 it will go to 20Mhz aswell! looks like a good IC but its now obselete as Nigel says infact all the chips ive looked at are!. I dont really want to start this project using really hard to find (and expensive) chips.

Surely there are other (new) monolythic function generator chips on the market. Or maybe i should look at DDS

 

[Nigel Goodwin]

Not as far as I know, these chips seem to have run their course now, much higher quality options are available (like DDS).

 

[RadioRon]

have all been obselete for years now.

Yeah, I guess I'm obsolete too. ..sigh.. Only good for management, and not much good at that.

Time to write my memoirs, I guess.

 

[Hero999]

You can get specialist ICs but I imagine a mircocontroller would work at low frequencies and an FPGA would be an option for higher frequencies.

https://www.google.com/search?hl=en...=DDS+Function+generator+schematic&btnG=Search