Function/sweep generator

Ok, I'm serious about wanting one, but I have no clue other than the very basics, so help a brother out here.

AF is 20 - 20,000 Hz right, 20KHz, so I'm assuming that I only need a generator that can go AT LEAST to 20KHz yes?

If no, and I'm making a connection that isn't there, please explain.

Also, why do I want it to sweep?

please give me some insight into the features that i need for audio work so I can get this over with. School labs aren't open in the summer, haha

thanks

I gave you a couple of answers in the black market...Also, I hardly use anything other than 100hZ and 1K-unless I'm checking out an eq or something. I'm sure there are many more sophisticated uses that I've never even dreamed of.

You really just need something that can put out a tone of somewhere near the frequency you want. Infra- and super-sonic tones, sweep gen, low distortion, et cetera are just nice to have, but not absolutely necessary. Not by a long shot.

I got one of these puppies and it's proven quite useful.

Peace,
Al.

Jameco sells a function generator kit for $25, their catalog number 20685. www.jameco.com

Bri

I just use a cd, 4 tracks, sine and square at 100hz and 1khz, It does the job and takes up alot less space then my old overkill function gen.

adam

Where did you get the audio tracks?
That's a good idea.

I almost forgot I did the same thing last summer. I think I used Wavelab. As I recall it has a tone generator feature. It gave you some amount of sine wave that I just cut and pasted until I got what I needed.

Matt

I founds some online tones here:

http://www.dogstar.dantimax.dk/testwavs/
and here
http://www.eminent-tech.com/music/multimediatest.html
and here
http://mdf1.tripod.com/test-tones.html
and probably dozens of other places.

Hey Matt, how's Lafayette these days? (I used to live there.)
Ever recorded at Sonic Iguana? I hear great things about it.

I used SuperCollider to make the tones. Best and most powerful softsynth ever. Its like Csoundx1000 and always growing.

http://www.audiosynth.com/

The sourceforge page has windows versions for you MS folks.

adam

The thing about any CD or computer generated signal (PARTICULARLY square waves) is that the waveform quality sucks due to the Nyquist filtering. I've looked at the output of a square wave from a "test" CD on a scope and it really sucks.

Bri

[quote author="Brian Roth"]The thing about any CD or computer generated signal (PARTICULARLY square waves) is that the waveform quality sucks due to the Nyquist filtering. I've looked at the output of a square wave from a "test" CD on a scope and it really sucks.

Bri[/quote]

Yeah, it does, but it is more then good enough for what most of us need. We do not need to get precise measurments, the sloppy computer generator waves will give us a visual of what we hear and confirm or deny what our ears suspect. Just like any function gen you can not rely on it and nothing else, you need to combine it with what your ears and brain are telling you. You know what the wave form looks like before it enters the circuit under test and you know what it looks like going out. If nothing else, its a good starting point, its dirt cheap and will give you an idea if you really need a function gen.

Also stay away from internet test tones. Use a softsynth of somesort to make the waves. It is what they are made to do, and most of them will creat better waveforms, and use a good mp3 encoder. Its almost free to try, so why not.

adam

adam

I build a function generator with a XR2206 chip. it work well .

is possible to find high frecuency oscillations by beating with a high frecuency oscilator?

[quote author="12afael"]I build a function generator with a XR2206 chip. it work well .

is possible to find high frecuency oscillations by beating with a high frecuency oscilator?[/quote]

The 2206 is what is in the Jameco kit, which is basically the same circuit found in the Exar application notes.

I can NOT imagine doing any design and testing without a good function generator.

Quality square waves will tell you MANY things at a quick glance via an oscilloscope, particularly if there are transformers in the circuit. I can also test all of the EQ sections in a recording desk for "go/no-go" at 1 minute per channel or less while watching the scope and listening to the test signal.

For aligning tape machines, a function generator has an incredibly flat frequency response and ultra-fast settling time for the sine wave output.

All MRL test tapes made the past 15+ years have (computer controlled) function generated test signals.

Downside: the sine wave output has maybe 1/2% THD, so it's useless for measuring distortion. For that I have my Amber test set.

Bri

[quote author="12afael"].....is (it) possible to find high frecuency oscillations by beating with a high frecuency oscilator?[/quote]

...with a swift kick between it's pins.

(ooooooh, that 1 mega hurts)

=FB=

[quote author="kato"]Hey Matt, how's Lafayette these days? (I used to live there.)
Ever recorded at Sonic Iguana? I hear great things about it.[/quote]

Hey Kato,
Lafayette is as good as it can be I guess. Sonic Iguana is pretty nice. They've built a second live and control room in the last few years. Mass acutally acquired the use of the whole building now.
I recorded there 3 times with my old band, but the last time was in '99. I just got back into music and recording in the last year and a half after a four year break. Anyway, my job is up in Sept, so I may be in your neck of the woods after that.

Matt

*EDIT* oops! duplicate.

Hey Ptownkid,

If you're still considering the XR2206 route, I just found two leftover ICs. They're yours if you want 'em.

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=1209617&N=401

av built function gen and old school drum synth "poo-poo - feels like i'm in love" if you can remember that classic.

Has anyone found a free function generator design online?

That Jameco kit looks tempting at $25 - but our household entered super budget mode after having a child and losing an income. I'd like to build one with the parts I have, etch my own board, and just buy a chip. (Cheapsake, I know.)

I found this:
http://www.loetstelle.net/projekte/xr2206/xr2206.php
(not in english - but well documented in the universal language - a schematic.)
Babelfish gives some pretty reasonable translation (understandable.):
[quote author="babelfish"]
Enterprises becomes the module with approx. 12V DC voltage. A virtual mass on half operating voltage is formed, the mass exit of the output signal is thus on this potential. This is to be considered when attaching the module![/quote]

-----180° topic shift-----

[quote author="mateo"]Hey Kato,
Lafayette is as good as it can be I guess. Sonic Iguana is pretty nice. They've built a second live and control room in the last few years. Mass acutally acquired the use of the whole building now.
I recorded there 3 times with my old band, but the last time was in '99. I just got back into music and recording in the last year and a half after a four year break. Anyway, my job is up in Sept, so I may be in your neck of the woods after that. [/quote]

Somehow, everyone I meet from Laf. knows Mass.
He used to book shows for an under-21 club back when I lived there. He even booked my shitty band (bless his heart) on some fairly big bills as the opener - and trust me, we sucked; it was only out of kindness and scene-support. Great guy.

There's another lab member in Laf. you probably know (JCharles00) - active in the scene - played in Summerfield, and Uncle Stumpy's Porn Funk Band. (among others.)

What was your band called? Kato

I bougt Wavetek on ePay, paid $40 including shipment ($800 retail), soldered one wire back to transformer.