Wave Generator IC Help...Please!

I am new to actually building something by soldering component to a board. I have tested and done some troubleshooting in the military when needed, so I am basically going into this half blind. I am building a function generator as my first piece of test equipment for my bench. There is an existing schematic for this project from 2005. I have been looking around for a newer (better), wave generator, than the one that is currently planned. I am trying to find a database, website, or whatever, that can provide a list of these waveform IC's. For example, which kind of waves(I want several) and how many, age, software required, price, and so on. I find individual IC's, but nothing that will help me figure out which are the latest and greatest. If I am going to build function generator, I want the IC to have a good number of different waves, a relatively new(updated) software package that comes with it. I would also like to be able to compare these to each other. So, bottom line, Does anyone know where something like this could be? Any help would really be appreciated!!! I have searched and have come up relatively empty. Thank you.

Jeff

Hi Jeff

Did you try 8038 function generator. Well, IC function generator do work well but if you really want to develop a good function generator with flexibility in its range and signal quality, you have to go for multiple circuits.

Darkseid

darkseid said:

Hi Jeff

Did you try 8038 function generator. Well, IC function generator do work well but if you really want to develop a good function generator with flexibility in its range and signal quality, you have to go for multiple circuits.

Darkseid

Click to expand...

Thank you for responding! I did look at the 8038, ICL8038CCPD at Digi-Key. They say it is obsolete, and unfortunately, I have been finding that everywhere. Where are the new ones? I'm utterly new at this, could you elaborate on what you meant by multiple circuits? I'm certainly not looking for the easier way out, so if I can build a better and more functional test set, then I am interested in learning how!

Thanks.

73,

Jeff

You didn't say what project you were building, but I think you need to define your requirements a little first: what frequencies and waveforms, does amplitude flatness matter a lot or not much, do you require sweeps, etc.

I used to calibrate and repair Agilent function generators and I've built some of the small crude multiple op amp FGs. They're only good for audio frequencies and make sloppy waveforms with crossover distortion. I've considered building something based on the XR2206 from Exar but haven't yet.

It looks like these various analog function generation chips are gone or going away. DDS (direct digital synthesis) chips are replacing them but require a microcontroller. Try browsing this stuff: Function Generator Electronic Circuits. You might find something useful.

I attached a PDF of the project I want to do. It will be a test tool for my bench. I would like to get as many waveforms as possible of course. I was thinking at least 1 Hz to 30-40 Mhz, and I know nothing about amplitude flatness and sweeps yet LOL! I just wish the newer IC's would be more evident, rather than finding all of these obsolete IC's! Thanks,

73,

Jeff

As I look around this forum, I see many questions being answered that are much more complex than this one, yet I have had a total of 2 people that have helped out of hundreds of views between two separate posts. Have I worded the question wrong? Is my question not worth answering because it's considered common knowledge in these circles? I apologize for not bringing more electronics knowledge to this forum, I wouldn't have registered if I'd known I would be shunned. Thank you to those who stepped up, I do appreciate it. I see though I need to go elsewhere to get help, since here I haven't been deemed worthy. Very disappointing.

Patience and persistence are needed here. There are many vagaries to traffic and help on this forum. You might try changing the title to "Function Generator Project", not because it's any better, just different. The DIY function generator projects and kits that I've found are not capable of more than 10 MHz and most are around 2 MHz. It may be that no one has a good solution and it's one of those pieces of equipment that can be purchased less expensively than built. There's nothing wrong with the project design you currently have if you can get the parts.

Your level of experience and knowledge are not a problem. I've seen posts on here from people who clearly had no idea what a wire is used for, much less any deep theoretical understanding.:razz:

One other thought. Sometimes people who have good information for your request will skip over it if it appears to have been answered already, so reposting after a while may work.

It's growing tiresome coming up with ways to ask a question to procure a reasonable answer here. Thank you Dave, I will continue to correspond with you in private, but I find that it was a mistake to think that I would be welcome here.

I am sorry you find it tiresome asking questions to get a reasonable answer, but I think you have had a good response on the board considering the questions.

One of your threads was about a problem with the AD9833 evaluation software giving runtime error "48" File not found "parllio". I think such a question is best directed at Analog Devices. It is a bit of a long shot to expect someone on here to have used the evaluation board and found and fixed the same error. It seems rather churlish to then complain about the lack of response to that thread. The Analog Devices ADA4898 Spice model seems to have a floating node 9 in it. If I posted a question about that on here I am sure I would also get zero response. If I need that fixed I will raise a support case with Analog Devices. I suggest you do the same.

Your responses on this thread seem pretty good to me, given the questions. You had the suggestion of the 8038, an alternative to it which isn't obsolete, and the suggestion of DDS.

Your post attaching the pdf of the DDS generator saying "this is what I want to build" didn't actually seem to have a question in it. What answer were you expecting when there is no question?

There are probably some DDS experts on the board. A quick search should find out where they hang out. A post on the right forum such as "DDS for 1Hz to 40MHz waveform generator?" may get a suitable response which will get you moving in the right direction. "Wave Generator IC Help...Please!" in the Hobby forum probably isn't going to get noticed by the right people.

Don't assume that threads with lots of replies are good ones. The best threads have two posts - the question and the answer.

I hope you get the help you need. For the record - I know nothing about DDS and have never used a waveform generator IC!

Keith.

i have an unused ICL8038CCPD if you want cheap. PM me .: )

HI Jeff

Since function generator is basically a conglomeration of several waveform generators, I would recommend that you first start building circuits which can produce individual waveforms like sine wave, square wave etc. If you go for waveform ICs, it will save time but we wont learn a lot from it. For example:

1. Use amplitude stabilized wein bridge oscillator for sine wave. Check the flexibility in frequency.
2. Develop a circuit for a high quality square wave(you may need a DSO for this)
3. Now see if you can reduce hardware/no of components for the combined circuit.