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Author Topic: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )  (Read 41095 times)

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #45 on: October 23, 2009, 06:46:07 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 .

Dankie, I've pm'd you with more info but I plan to charge a modest amount for a preprogrammed chip with full colour laser printed build instructions and sources for all the components at the cheapest price, paypal through ebay. Existing customers will then be offered further firmware enhancements at a much reduced rate. It will make it easier for someone to build, just plug and play really. Also it will give me incentive to greatly enhance the software and produce a better product that will make a good peice of equipment with very high specs for anyones bench.

stprue

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #46 on: October 23, 2009, 06:53:16 PM »
I'll buy one  ;)

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #47 on: October 23, 2009, 07:08:26 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.

GK, I hear you! codeland is my favourite sanctuary.

Ever since I fried a 50MHz analog scope when trying to look at a cars ignition timing when I was a teenager, ever since then I am more careful.

I have thought about different schemes to guard against fast back transients should they occur. In my initial pure sin experiments I don't expect major surgeback through the oscillators, but when I go to square, well things might get rough.

Having said that, even with initial sin build I will definitely be putting isolation into the feedback path:

[1] signal in

[2] rectify

[3] smooth

[4] bleed via 1ohm 5w resistor to ground (to give a DC voltage proportional to output current)

[5] tie high side of bleed resistor with neon and avalanche diode in parallel to ground (safety path to GND on overvolt)

[6] optoisolator

[7] log opamp to give compression and so more range

[8] then into the microcontroller ADC to calculate realtime RMS power and display as necessary

I suppose it wouldnt hurt to put neons and parallel avalanche diodes to ground on each oscillator channel also, negligable capacitance is added, whether they would sink fast enough to protect my RF output amplifier chips, I don't know? Maybe you could try this after you fix your uProcessor.
« Last Edit: October 23, 2009, 10:23:08 PM by Yucca »

giantkiller

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #48 on: October 23, 2009, 09:31:55 PM »
Famous last words: I'll be more cautious next time?
I have pulled all chips and am using the board as a holder for just the uproc. I have tried 3 of the 4 uprocs. All the same results. With nothing but caps, diodes, + a DC2DC cnvtr the processor runs and communicates. The voltage is +5v and fine. With one uproc left that hasn't been plugged in I need to program it in another setup in case this build is breaking uprocs. Eek! I buy more, but still.

--gk.

Mannix

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #49 on: October 24, 2009, 01:16:01 AM »
I dont know if this is useful, but the cro i fried with my 3 channel ring had so many faults that seemed un related to the input channel. the faults were in the vertical amplifier,power supply and timebase ..separate,unrelated  faults it seemed ..I had a manual . I never succeeded in fixing it. It was a nice anritsu 100 mhz

This cat we chase sees pn junctions as cotton candy..so it seems

sparks

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #50 on: October 24, 2009, 06:24:02 AM »
   Magamps are used in all sorts of highenergy fields including radioactive.  If the acsupply to the magamp is uhf captured on a dipole antennae.  Instead of just dumping the carrier so as to obtain the modulation riding the carrier we filter and store the carrier in a resonant cavity.  Effecting a lowering of the frequency and a rise of amplitude.  Waves sitting on top of waves and beside them.  In other words taking uhf and converting it into non radiating khz.  After enough power has been collected the magamp bias supply and control circuit can be powered by the ac input.  The amplification occuring at a low frequency closed circuit whilt the input is open circuit. A portion of the signal used to amplify itself.  Amplify.  To make larger.  Lots of short wavelengths summed to create a longer wavelength.  The faster something changes the more energetic. Something changing 330million times a second expressed as something changing only 60 times a second

http://www.tpub.com/neets/book8/32n.htm
           





Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #51 on: October 24, 2009, 01:42:59 PM »
I dont know if this is useful, but the cro i fried with my 3 channel ring had so many faults that seemed un related to the input channel. the faults were in the vertical amplifier,power supply and timebase ..separate,unrelated  faults it seemed ..I had a manual . I never succeeded in fixing it. It was a nice anritsu 100 mhz

This cat we chase sees pn junctions as cotton candy..so it seems

Hi mannix

RIP, sounds like you put some monster spikes into the CRO ground system.

were you feeding the ring with squares or sin? I'm guessing square/PWM?


Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #52 on: October 24, 2009, 01:50:52 PM »
   Magamps are used in all sorts of highenergy fields including radioactive.  If the acsupply to the magamp is uhf captured on a dipole antennae.  Instead of just dumping the carrier so as to obtain the modulation riding the carrier we filter and store the carrier in a resonant cavity.  Effecting a lowering of the frequency and a rise of amplitude.  Waves sitting on top of waves and beside them.  In other words taking uhf and converting it into non radiating khz.  After enough power has been collected the magamp bias supply and control circuit can be powered by the ac input.  The amplification occuring at a low frequency closed circuit whilt the input is open circuit. A portion of the signal used to amplify itself.  Amplify.  To make larger.  Lots of short wavelengths summed to create a longer wavelength.  The faster something changes the more energetic. Something changing 330million times a second expressed as something changing only 60 times a second

http://www.tpub.com/neets/book8/32n.htm
         

Nice link about magamps, I will read that carefuly this evening.

I'm worried about spikes coming back through control coils and frying my RF amp chips and maybe also my DDS chips especially when I go to square wave mode.

Do you have any ideas for protecting semiconductor OPs against spikes? I'm thinking Transient Voltage Suppression (TVS diodes) which avalanche at say 70% of IC max and then in parallel to those put neons to take the brunt of the later current and so protect the diode junction, I'm wondering if the neon would be fast enough to take the heat. If the TVS fails it will go short so worst case is that the TVS are just pricey fuses.
« Last Edit: October 24, 2009, 02:37:27 PM by Yucca »

giantkiller

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #53 on: October 24, 2009, 08:06:18 PM »
Quote
Regardless of the amount of load flux or polarity of the load voltage, there is no net effect of load flux on control flux.
I see this as an isolation issue and that the mag amp can be used as a part of the feedback loop. This has been said before but I see in now a little different.

--gk.

sparks

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #54 on: October 25, 2009, 02:30:44 AM »
    Even tubes have a hard time with reflection.  That's why we have microwave ovens nowadays.  Standing waves would setup inside the tubes of the day and toast the grids.  Whereas the cyclotrons create a spoked electron field that is spun.  The moving charge of the electron bunch creating waves in resonant cavities of the anode as the spokes alternately align with the anode cavities.  Ingenious device.  And I believe it is at the heart of the matter with the tpu.
Free electrons will orbit at a given cyclotron frequency about magnetic field lines.  We now have moving mass simply by providing free electrons and a magnetic field..  Where does the energy come from that allows the electron to move in a predictable drift or current.  In a torroidal coil the electron drift will be determined by three forces.  The polidal field the magnetic field and the gravitational field.  One electron drifting 1mm a second isn't much power but billions of them is.  Again where does the power come from that allows an electron to move.  Does an electron moving from cathode to anode effect the cathode anode potential if the electron never reaches the anode plate?  Electrons have moved but never reached the other side of the capacitor allowing the capacitor to remain charged.  Unlike when a capacitor is discharged into a closed circuit there is no exchange of charged mass in the two capacitor plates.  But there was an electron acceleration in the field between the two capacitor plates.  Adda magnetic field perpendicular to the polidial field and the electron acceleration now takes on a curved path.  Stop the polidial field and the electron movement spirals about the magnetic field lines.  In a torroidal coil there happens to be a conductor field full of free electrons in geometric aligment with the electron drift about the magnetic field lines contained within the core of the torroid. One more time where does the energy come from that causes an electron to move or orbit a magnetic field line. 

dankie

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #55 on: October 25, 2009, 02:34:42 AM »
Then maybe sparks you can build an device and show us how you do it .

sparks

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #56 on: October 25, 2009, 04:29:27 AM »
Dankie

   I am asking the question about what makes electrons move about a magnetic field line or a neucleus for that matter  because I DONT KNOW.  I do know that whatever force or combination of forces that govern unbound electron motion is an important thing to figure out.  So I"ll just keep on asking questions and researching until I know and then I'll tell everybody I possibly can as many times as I can what the fuck is going on.

Yucca

     Back in the day I worked alot with unijunction triggering of scrs.  They were the fastest things around with the least drop.
The ujt would have to be heatsunk to last as it is purely a resitive element but if it picksup the field reversal and triggers the scr to shunt the reflection it may work as an active transient suppression device.  If it works I wouldn't waste the current on just heating though.  The ujt would act as a reversed field sensor and fire the scr into conduction until the transient voltage dropped below the holding voltage needed for scr conduction.

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #57 on: October 25, 2009, 06:08:46 PM »
A short video showing the stability of one of the DDS modules.

A digital radio receiver is tuned into 40MHz LSB and we hear the audio tone of it heterodyning with the DDS module also set around 40MHz.

When a Tektronix FG504 undergoes the same test it falls rather short.

http://www.youtube.com/watch?v=6nMC93-TAy0

Sorry about the crappy video/audio quality.

sparks

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #58 on: October 25, 2009, 08:09:27 PM »
   Nice oscillator I can see why you are worried about frying it.  No way to use optical isolation for your finals?

giantkiller

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #59 on: October 26, 2009, 03:38:37 AM »
@Yucca!
That is one sweet setup and test with good solid results!
How are you going to synch or phase adj the 3 DDS60 units?

--gk