The PMT in control of the Devil

[Harry Dalek]

Looking at this further it should be possible to get the frequencies required from one 4060.

i have only really tried 400 and 12 and 25 hz same time out of it that runs the other frequencies out a touch slower line rate wise.

Three frame frequencies of 12.5, 25 and 50Hz, plus line frequencies of 200, 400, 800, 1,600 and 3,200Hz. Also 6,400 and 12,800Hz should you need them. Choosing the appropriate line and frame rates gives you quite a wide range of lines-per-frame all based on powers of two.

That sounds good thats every thing you could want i would be pleased with that !

Harry, would this be enough for what you require?

Beautiful ..Steve thats great

Klaas's Triple Waveform Generator used CD/HEF parts, what do you plan to use as the timing components may be different?

As is i think the high range would be 500hz or so ...the cap might need switching this will change the frame rate as well i hope to the ranges you mentioned above...i think the resistors can be kept as is .

Steve A.[/quote]

[Steve Anderson]

As is i think the high range would be 500hz or so ...the cap might need switching this will change the frame rate as well i hope to the ranges you mentioned above...i think the resistors can be kept as is .

If the frequencies I mentioned in my previous post are what you need there is no need for capacitor switching/variation unless you want odd frequencies like 500Hz. I suggest you keep with the frequencies as I listed unless you want odd line/frame rates or have another reason.

Steve A.

Chip type? It does make a difference. i.e. CD/HEF or HC? Also supply volts.

[Harry Dalek]

If the frequencies I mentioned in my previous post are what you need there is no need for capacitor switching/variation unless you want odd frequencies like 500Hz. I suggest you keep with the frequencies as I listed unless you want odd line/frame rates or have another reason.

OK Steve yes thats fine i was only saying set at 400hz i think it was pin 13 pin and out of pins 1 and 2 were 25 and 12 hz ...32 line fine but i was wanting some thing like what your working out so yes ///500hz or so was the oscillator as with my part top range but it would of changed the frame rates no good for the monitor !

Steve A.

Chip type? It does make a difference. i.e. CD/HEF or HC? Also supply volts.

[/quote]

i was running mine on 5 volts M74HC4060B1

[Steve Anderson]

OK, thanks Harry, I'll get on with it...

Steve A.

[Steve Anderson]

Here 'tis. You'll have to fiddle around with the Rt values, but all being well they should be not that far off...at least I hope +/-50%.

Don't forget some decent bypassing/decoupling on the supply rail.

Steve A.

I updated the drawing by changing the font, no electrical changes otherwise.

[Harry Dalek]

Here 'tis. You'll have to fiddle around with the Rt values, but all being well they should be not that far off...at least I hope +/-50%.

Don't forget some decent bypassing/decoupling on the supply rail.

Steve A.

I updated the drawing by changing the font, no electrical changes otherwise.

Thank you Steve ! now thats a really a elegant solution ! i am sure this will be of use to others as well great stuff ! I will let you know how it gos working onit now .

[Steve Anderson]

OK, keep the stray capacitance around pins 9, 10 & 11 to a minimum.

Steve A.

[Harry Dalek]

OK, keep the stray capacitance around pins 9, 10 & 11 to a minimum.

Steve A.

OK Steve knocked it up only problem i don't a meter to check my capacitors so i go by the code and ceramic capacitors i am not great working those out ..what i thought was a 100pf it was giving half frequency results i tried a 220j which is a 220pf i think its showing 42 hz on pin 1 should be 50hz .
Using a 10k and 10 k trimmer where you mentioned in place of the 15k so its on highest frequency results .
So really its just a matter of fiddling with the capacitor and that trimmer resistance it would be in range if i dropped the 10k fixed resistor a touch .
But good results for a quick knock today .\
Thanks again for the help here Steve

[Steve Anderson]

Yep, I did say you'll have to fiddle-arse around with the values. Again this is analogue circuity on logic silicon which has a huge spread. But once you get it there it should stay there. If you have to change the 4060 for whatever reason you'll probably have to go through this same exercise again.

Seeing as your scope has four digits for frequency use the 6.4kHz output to set the frequency, this will give you the best precision. The other outputs will fall into line.

Steve A.

[Harry Dalek]

Yep, I did say you'll have to fiddle-arse around with the values. Again this is analogue circuity on logic silicon which has a huge spread. But once you get it there it should stay there. If you have to change the 4060 for whatever reason you'll probably have to go through this same exercise again.

Seeing as your scope has four digits for frequency use the 6.4kHz output to set the frequency, this will give you the best precision. The other outputs will fall into line.

Steve A.

No worries Steve will do ,i will finish it off tomorrow much less than i was expecting to do when i started walking up this road fiddling with a few part valves is ok

[Harry Dalek]

Got it adjusted Steve as with the changes in the overlay in your schematic .
I would say both trimmers should be the multi turn type.
Once you have the correct frequencies lowering the 10k fixed resistor with the extra trimmer replace with a fixed resistor if you could be bothered .
My capacitor is a 220j which i think is a 220pf i don't have a capacitor meter at the moment so how far off or correct to 220pf it is i am not sure .
Working now on finishing off the sawtooth circuits which will drive the raster on the oscilloscope .
i am thinking of just making the video signal with sync pulse added to the video so will need a monostable to adjust the pulse width also since i have framing pulse suppose i could add this as well but getting ahead of my self ...need to get the saw tooth circuits operational and synced to the clock .
BTW i must of been scraping the probe on the 25hz test photo and the 12800khz photo hard to see the 8 but it is an 8.

[Steve Anderson]

A good result. Though I don't know why the scope says 12.00Hz when it should be 12.50Hz (half of 25Hz). Maybe there's a limit on its low-frequency measurements.

Odd capacitor, 222 would usually indicate 2.2n, 2 then 2 followed by 2 zeros = 2200p = 2.2n.

In an ideal situation the ramp generators could do with a re-design now they're not operating at a single fixed frequency. I'll have a think on this, it's not an easy task.

Steve A.

Correction - it's 220 which should be 220p as you say. Quite a way off the design formula, but if it works, so be it.

[Harry Dalek]

A good result. Though I don't know why the scope says 12.00Hz when it should be 12.50Hz (half of 25Hz). Maybe there's a limit on its low-frequency measurements.

Yes its either 12 or 13 hz no in between on the low readings Steve

Odd capacitor, 222 would usually indicate 2.2n, 2 then 2 followed by 2 zeros = 2200p = 2.2n.

I will study this ,i recall when i did have a meter makes you lazy checking the code.

In an ideal situation the ramp generators could do with a re-design now they're not operating at a single fixed frequency. I'll have a think on this, it's not an easy task.

Steve A.

OH OK i recall on the devil 32 then resistance change needed on the frequency control for any thing above also on the frame side its now direct to the clock i am not sure may just sync to 25 50hz also..
i will be out for the morning Steve but check the posts when i get home .

[Harry Dalek]

Got one of the saw tooth oscillators to work correctly the other playing up could be the capacitor was not showing up on another capacitor i was using just for testing.
First two little scope shots are the line frequency range free running with a trimmer replacing the fixed frequency resistor R724.

Second the frame its giving me a new one for a problem i have not come across before.

[Steve Anderson]

As I mentioned, the original ramp generators are not really designed for multi-frequency work without a lot of capacitor and resistor switching. Have a look at the circuit diagram of an analogue oscilloscope timebase. You'll see what I mean.

It is very easy to do this with a small 14-pin DIL microcontroller but I guess that's maybe not the way you wish to go. It measures the input frequency and sets the charge current of the capacitor such that it's a constant amplitude whatever the frequency. It would be no harder than using a 74HC00.

For the time being perhaps some thought needs to be put into this without using a micro.

Steve A.