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Author Topic: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )  (Read 41093 times)

Peterae

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #30 on: September 26, 2009, 11:57:32 PM »
Hi Yucca
Sounds amazing, most wouldnt realize or appreciate the time you will need to put into this.

The spectrum is a great idea and could be very handy indeed.

The maximun ADC peak would be good if it could log the 3 best peaks maybe in order if you are able to, i am thinking there maybe more than 1 sweet spot which could give clues to what's going on.

Peter



Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #31 on: September 27, 2009, 12:02:16 AM »
@GK & Otto,

Squares may be good for TPU, that's why I also want to include the following stages outputing into 3 seperate front panel BNC sockets:

variable opamp -> FET driver -> N-FET (sourcing external power)

this should give me PWM capability (10...90%) on all three channels up to maybe 10MHz. Of course they will also be perfectly phase locked and very frequency stable thanks to the temperature compensated main oscillator.

If anyone else wants to build one I will send the code and instructions to any other OU member gratis.

Yucca.
« Last Edit: September 27, 2009, 01:43:39 AM by Yucca »

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #32 on: September 27, 2009, 01:03:00 AM »
Hi Yucca
Sounds amazing, most wouldnt realize or appreciate the time you will need to put into this.

The spectrum is a great idea and could be very handy indeed.

The maximun ADC peak would be good if it could log the 3 best peaks maybe in order if you are able to, i am thinking there maybe more than 1 sweet spot which could give clues to what's going on.

Peter

lol Peter, you know more than me about time spent with MCU software, assembler language is MUCHO work and gets VERY difficult in larger projects. I have written one small system with GUI in assembler but mainly mantained other systems code, the programmers comment text is VERY needed and even then it's painful.

good idea about 3 best peaks.I would have to write some routine to record only local gradient maxima otherwise it would only record several peaks from the same overall highest curve.

Yucca.

giantkiller

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #33 on: September 28, 2009, 05:26:24 AM »
Good work! Keep on truckin'

@GK & Otto,

Squares may be good for TPU, that's why I also want to include the following stages outputing into 3 seperate front panel BNC sockets:

variable opamp -> FET driver -> N-FET (sourcing external power)

this should give me PWM capability (10...90%) on all three channels up to maybe 10MHz. Of course they will also be perfectly phase locked and very frequency stable thanks to the temperature compensated main oscillator.

If anyone else wants to build one I will send the code and instructions to any other OU member gratis.

Yucca.

otto

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #34 on: September 28, 2009, 07:22:08 AM »
Hello all,

@Yucca

very nice work.

As least you cant damage this oscillators like Im doing it with mine because of runaways every day, ha,ha.

Otto

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #35 on: September 28, 2009, 05:03:34 PM »
Otto & GK, Cheers guys, your work in TPU seems deeper than average, it'd take me weeks of reading to catch up on what you guys have done. Runaways sound exciting otto!

While I wait for bits to arrive I've designed a touch sensitive circuit, I hope to have the one metal dial be also touch sensitive so scanning can be performed with one control in one hand and no strain from pushing switch.

The circuit sets up two of the NORs as a 100kHz RC oscillator. This oscillator then pumps up the capacitance (which is touchpad to ground) the capacitance is leaked through the variable pot.

When someone touches plate the capacitance to earth increases greatly and so the resistor can't pull it down fast enough. the fourth nand buffers the output and debounces with 22uF electrolytic.

The microcontroller interprets a momentary touch between 10ms and 200ms as a valid user press.

Maybe a working TPU will hash up the operation lol, but it does work fine a meter away from a 10W spark fired aircore LC at ~6MHz.

BeeSee

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #36 on: October 22, 2009, 01:40:16 PM »
Hi Yucca!

Hope your project went on smoothly! Can you update us on its latest progress. Thanks!

Ernest

dankie

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #37 on: October 22, 2009, 06:37:08 PM »
Give it time LOL , this is quite the engineering project .

When you *build stuff* you run into trouble and have to trouble shoot and solve that problem .

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #38 on: October 22, 2009, 11:48:08 PM »
As Dankie says, it does take time, I find most time on the project is thinking time away from the bench, and then programming time, probably  over 30Hrs now, if I don't like the code structure I often rip it back a little and then proceed.

But here's an update:

The software is done to initial beta stage and seems bugfree. Scanning with power sampling is now complete and runs at a reasonable 1200 samples per second.

Most of my parts have arrived, see photo.

On the left you can see the 3 x DDS boards with AD9851 synthesizers and AD8008 RF amps. I can't stress enough what a superb job Analog Devices have done with these ICs; I have a very good radio receiver (scanner) that is very stable. I programmed a module to output 60MHz. Tuned the radio in on sideband reception and it was spot on. When I listen to the heterodyne signal it is really solid and clean. I can set heterodyne to 500Hz and even at 60MHz the 500Hz tone is rock solid! When you try the same with analog oscillator the heterodyne will drift all over depending on temperature, proximity of hand, phase of the moon lol etc. And when you change the output load it will disappear from the radio.

Another good thing is that the 3 seperate modules are all VERY close in frequency. I can hear a small beat between two seperate heterodyne signals. But at the moment each module has its own xtal oscillator. I plan to feed them all from one clock in the end. But I'll build it up with three seperate clocks to start with.

Also pretty pleased with the jogwheel encoder. A nice bit of kit, made in japan for CNC machine control, ballraced and strong, nice clean output signal, works well with the micro. Also I will be able to isolate its case ground and my touchsense circuit works well on it.

The 3 bunches of black cables are chinese wifi extender cables, these were dirt cheap and superb quality. If you bought 6m of RG174 cable and the plugs and sockets from digikey etc it would cost quite a bit. These cost €5 all up delivered to europe.

Before I expand the software to 3D sweeping I will upgrade to 32kb memory. I have plans to make the 3D scanning have 3D gradient ascent to quickly hunt into maximas. To do a brute force scan (raster scan) of 1000 x 1000 x 1000 samples = 1billion samples, it would take almost 10 days to scan that at 1.2 kS/s. With gradient ascent I should be able to shorten that to hours. I will also have raster scan as well. This will be nice for exploring areas of interest when the data is transfered via USB to the PC, I will in the end write a small PC app with openGL viewer so I can see the 3D data set and peel layers back to look inside.

I will also make small RF shields with cardboard and alu tape for each module.

I've also got to work out the best conditioning circuitry for the sampling input, I probably want an optoisolator and maybe a log opamp with small knob on box front to adjust gain.

I will order a small alu chassis case to put it in next paycheck.

It'll probably be done in a few weeks. Before then I'll probably make a vid showing performance of the  DDS modules.

giantkiller

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #39 on: October 22, 2009, 11:48:15 PM »
A beautifully, extensive play of the mind and wonderful engineering!

Now when you want that device to run free at 60Mhz strap a hamster to the plate. That way you won't be around when it blows up.

Otherwise Saint Peter will be asking you "Well now son, What is that in your hand? You know we don't let that kind of technology in here. We have enough clouds as it is. And it also looks like your brought one of your own?"

--gk.

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #40 on: October 23, 2009, 12:24:33 AM »
A beautifully, extensive play of the mind and wonderful engineering!

Now when you want that device to run free at 60Mhz strap a hamster to the plate. That way you won't be around when it blows up.

Otherwise Saint Peter will be asking you "Well now son, What is that in your hand? You know we don't let that kind of technology in here. We have enough clouds as it is. And it also looks like your brought one of your own?"

--gk.

Cheers GK. I realise I'm covering similar ground you walked many moons ago. Your TPU sings vid is a classic, those sounds are real nice like an ambient track, with suprising complexity.

Lol, I don't plan to do any closing the loop (yet), all open loop with weak fuses.

I'm still wondering whether I should also use faraday cage or maybe I'd be better with a simple tinfoil hat lol?

I can't wait to start exciting some different winds with it. I'll probably play with pure sin first and then add fast comparators and FETs for squares later.

I've watched the vids lots of times and nothing screams fake, also one thing I will say is that the TPU subject is teaching me alot of new things, which is cool!

Yucca.
« Last Edit: October 23, 2009, 01:04:10 AM by Yucca »

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #41 on: October 23, 2009, 01:03:40 AM »
Hi Yucca!

Hope your project went on smoothly! Can you update us on its latest progress. Thanks!

Ernest

Welcome to the forum Ernest, I see you registered along time ago so you probably have quite a bit of background reading done already.

To give you and all a brief idea as to what I will be trying first with this box:

I will wind a circular collector loop 6inch diam, it will have a small trimmer cap across it for tuning.

On it I will place 3 collector coils, each covering 120 degrees.

I will excite each collector with different frequencies while sampling the collectors output power and scoping its output.

I don't expect to see COP>1 on this first experiment. But it will be interesting to see the 3D power distribution and if I see clusters of power I may try concentrating on that area and try to get clusters to join up with changes to coil geometry and tuning.

It should be good watching because I plan to make youtube vids of the 3D power structure slowly spinning in 3D frequency space and gradually unpeeling to the hotspots in the centre. I wonder what shape the distribution will be? Spherical, Ellipse, Curved seperate planes, curved lines, straignt lines? hmm?

Yucca.

BeeSee

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #42 on: October 23, 2009, 02:31:22 AM »
Million thanks for your prompt reply!
I am indeed a newbie and this is my 1st post, though I am a long registered member of OU.com.

My interest is not in the TPU (too advance for me to handle). I am interest to know more specifically how to build your 3-channel Pure Sin Generator. Hope your next video will cover the steps of the construction of this unit.

Will you all the success and Million thanks for sharing your valuable knowledge with us!

Ernest


dankie

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #43 on: October 23, 2009, 04:32:44 PM »
Yucca , I hope you wont be stupid enough to offer this for free , after all that hard work .

You know theres a potential market for this ...

If somebody can only copy it , then he must buy it .

giantkiller

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #44 on: October 23, 2009, 05:42:24 PM »
@Yucca,
Good job. This is quite the addition for any future attempts. You will be pleased. I am digging deep into my controller failure. Seems the BEMF or shockwave burned all my outputs of the uproc.
I am writing a program to toggle the output lines in a standalone mode. No usb comm. I am locking this little bugger in a cage and gonna poke it with a sharp stick!
No caveats. But I must relay this bit of advice. I put all my current efforts and resources into this device. Don't have a backup plan as in other types of test equipment to do this type TPU testing. I have shopped and I don't like the pricing behind the LF & HF multichannel signal genny with synchronization capability.
So this controller route is good. Jason did implement alot of safety features. But nothing to guard against user misconfigs, like putting a feedback BEMF at the SSR gate drive that feedsback into the controller with no firewall. And I have a firewall safety that I built 2 years ago sitting there unattached! Argh. In my zeal gained from other builds and tests I ran roughshod over this new build and cataclysmically denied myself the favor of being peaceful in my attempts. So let this be a lesson to ya! I do all the blowin' up stuff here. LOL.
I am in code land and that is very dark and addictive real estate.

--gk.