A New Voltage Controlled Quadrature Function Generator

Danno Gee Ray · Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA

Thanks for the heads up.

I hope all is well for him, and that he has a speedy recovery.

bugbrand · Posted: Mon Oct 29, 2007 1:42 am Post subject:

Slices at the end of the week!
*************************

I have been working again on this and I am so damn sorry for not having produced anything earlier. See, the 1st design I did felt really messy - I wanted to tidy that up, but it hasn't been at all easy using single-sided boards and with keeping things compact. (It still ain't great, either!)

I had a duh moment yesterday.. A month or two ago I'd actually got around to re-doing the layout but then I'd somehow completely forgotten about it - it just needed to be wrapped up. So thats what I'm doing now.

I know its risky to say 'any day now' at the moment, but.......

Danno Gee Ray · Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA

Glad to hear you're doing well. Thanks for picking this back up, I appreciate your willingness to work on this. I think I'm the one who fell through the cracks on the other option, and just want to be able to build this circuit.

Thanks again

Thomas Henry

bugbrand · Posted: Tue Oct 30, 2007 4:41 am Post subject:

Heya,

Yes, this was too much of a battle and, again, I'm really sorry to have taken a freaking age to do this. But now we're (finally) ready:::::

http://bugbrand.co.uk/pages/PDFs/TH_QFG_BugPCB.pdf

- PDF with toner-transfer image ready to go
- parts layout
- redrawn schem just for clarity.
- though refer to Scott's original QFG page for all the decent info!

A few things to note:
1) I haven't actually tested this yet! Well, not this exact version - the layout has changed just a bit from the one I built so I have complete faith that this'll work straight off. In fact, I may well have to build me another one soon 'cos I love it!
2) There's an extra timing cap pad so you can have two ranges. My current setup has one at audio osc speed but there's an upper limit to the audio range defined by, I think, caps C3 and C4. Still you can get up to nearly 1kHz without problem - or go much much much slower with big caps!
3) Note that I've used BC547/557 for the transistors - simply rotate 180deg for 2N3904/6
4) The layout is for my standard of 16mm Alpha pots spaced by 0.8" (roughly 2cm apart). You could easily edit this to something else if you don't like PCB mounted pots.
5) sorry there are so many jumpers.....

Enjoy!

And, for those who've already expressed interest in Randal's PCBs - please wait for a bit longer for the situation on that to resolve rather than jumping ship and going the ferric chloride route.!.

etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

Great stuff bugbrand. Thanks!

Danno Gee Ray · Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA

Thank you Bugbrand,

I have been in contact with Randaleem and will be able to order a PCB. I am grateful to you for doing this though for the community at large.

Well done.

etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

Finished mine

thqgbugbrand.jpg

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TH Quadrature Generator

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etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

Still need to debug though, as all waves are clipped at +2V. Below are the 180 and 270 outputs:

thqg_scope.jpg

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Clipped Waves

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etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

By the way, bugbrand, the R36 next IC2 should be R26.

krisp14u · Joined: Nov 11, 2006 Posts: 206 Location: uk

The Alison Project · Posted: Tue Oct 30, 2007 7:20 pm Post subject:

Thanks bug, got the parts and I am ready to go.

-
Chris

etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

bugbrand · Posted: Wed Oct 31, 2007 4:05 am Post subject:

Wow - amazing!
Nice & superquick work!

Etaoin - do let us know how the debugging goes - I'm very keen to make sure that this layout is indeed correct (as I mentioned, this layout is a little different from the one I used originally) - I doubt I'll have time to whack one out myself before my op.
And thanks for noticing the wrong R label -- I'll update the pdf once I've got a moment.

And I'd forgotten that I was also going to recommend a bicolour LED driver add-on too... Like what I did for the Mankato - BiColour leds are mesmerizing to watch! This is the super-simple circuit I employed for that::::

bicolourLEDdrive.jpg

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Simple driver for Bicolour LEDs

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etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

No need to debug, it was just me being silly. Because it was easier, I hooked up the scope input to the legs of the LED. The clipping is just the LED conducting. The real outputs are all fine.

So I can now report a confirmed build. The PCB is fine.

bugbrand · Posted: Wed Oct 31, 2007 4:30 am Post subject:

Great! & well done for such a fast turnaround!

Does everything fit ok? I notice things look quite tight around the supply input beads / offset trim - - - - is a bit more space needed there, perhaps?

etaoin · Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL

Yes, that is very tight. Caps didn't fit in between the beads (they stick out on top) and C13 and R39 bump into IC3. I guess you intended smaller trimmers anyway (Bourns 3266W?) as the ones I used didn't really fit anyway.

shawn · Joined: Dec 13, 2005 Posts: 209 Location: savannah

Bug,

I built 2 but only had time to test one. Works perfectly. Thanks for putting the effort in providing pcb artwork! I did notice that R36 is still twice in the pdf.

janvanvolt · Joined: Nov 24, 2005 Posts: 285 Location: Mainz, Germany

Bugbrand: hich bicolor LED's do you use ? most of the ones here available do have 3 legs and not 2 Sad

6079smith · Posted: Fri Dec 07, 2007 2:35 pm Post subject:

janvanvolt · Joined: Nov 24, 2005 Posts: 285 Location: Mainz, Germany

Link does not work Sad

But i looked for "bicolor led" and found the right ones. thanks for pointing out Smile

bugbrand · Posted: Sat Dec 08, 2007 5:27 am Post subject:

Cool - good you found' em. I get them in the UK from Rapid

6079smith · Posted: Sat Dec 08, 2007 11:11 am Post subject:

shawn · Joined: Dec 13, 2005 Posts: 209 Location: savannah

I used a software oscilloscope and used it in the audio range (with the mod that is explained regarding C12 and did it that way. The one thing you will need to do in order to use this method is attach a 1M pot so you can lower the volume of the signal otherwise it will chop off the tops/bottoms of the waveform.

Thomas Henry · Posted: Sun Dec 09, 2007 4:48 pm Post subject: