CMOS Divide by 5.9 Cicuit

in software using "bit bang" method.

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that's kind of hard as 5.9 is not a clean factor of 32.

which CMOS features do you need? and how close to 5.9 do you need to get.

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"get's out calculator.. punch punch.." if you divide 32,768 by 5554 you get 5.8998... Hz. 5554 is even so reset counter after 2777 and then a divide by two as the last step to get your square wave.

George H.

"Dividing down by 5.9Hz increments" doesn't make sense. What do you really want?

I assume that you want a signal with a frequency of n * 5.9Hz, with you choosing n, and that you want to use the crystal as a frequency reference.

Yes? No?

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standard method is to multiply by 59, then divide by 5 and last step divide by 2 to get 50% duty cycle.

The way I read his requirement is to start with 32,768 Hz, and do some logic to get outputs at 32,762.1 Hz, another at 32,756.2 Hz, another at 32,750.3 Hz, etc., etc., etc.

Seems that a microprocessor would be the best solution. Start with 32,768 Hz, multiply it up by some factor, then use a software counter to click off the outputs.

Clarification, Ken??? How many outputs are you after, and what are the specific frequencies?

Dave M

He says steps of 5.9Hz, not divisions ratios of 5.9, 11.8, ...

But yes, as soon as he tells us what he _really_ wants, I'm sure that we can help him.

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I am sorry my orignal explanation was unclear to some readers.

It is easy to generate 32Hz with a 32,768 clock crystal and a CD4060.

I then would like to produce from this four or five frequencies that all differ by the same number of Hz.

To take a simple example, if that was 4Hz I would get 28, 24, 20,

16Hz, and so on.

Since coding is not one of my skills, can this be done with logic IC's? Maybe something involving sums and differences.

I could also use a separate generator for each frequency, but was hoping for a more efficient method, if there is one.

Ken Knowles

Still not real clear.

since a crystal is a crystal and soundcards use crystal clock, you could directly drive a soundcard generate your tone(s) individually or all at once.

You can get really fine steps that way

So, in clear language, you'd like to create 32Hz, 26.1Hz, 20.2Hz,

14.3Hz, etc, down to ???, from one 32768Hz source, all with 50% duty cycle. That's probably not trivial in old-fashioned logic, but a multiple DDS algorithm in a tiny microcontroller could come pretty close with relative ease.

Do you mind telling us why you want to do so? Often the *real* problem is easier to solve that someone's weird idea of a solution.

Jeroen Belleman

Since I don't have coding skills, it seems the opnly viable solutuion is to build a separate generator for each frequency.

Thanks to all for the helpful suggestions.

Ken Knowles

I think I may have figured out a way to get something close to the result I am looking for.

The CD4060 with a 32,768Hz crystal will output a 32, and 8Hz squarewave.

If I filter these into sine waves, what is the procedure for having them along with their sum and difference frequencies all together in one signal?

IOW to end up with a repetitive arbitrary waveform comprised of 40,

32, 27 and 8Hz.

Ken Knowles

take 32 and 'multiply' it 8 in something like a MC1496

if done well, that will produce 40, 32, 27, and 8

a MUCH simpler way is to drive your stupid soundcard with a .wav repetitively. use the standard 48kS/s to be an EXACT multiple, use octave to make the .wav file and you can get equal amplitude ANY phase you want, complete control and not even have to breadboard anything. All these tools are FREE to work with, too.

arrrggg! that was NOT handwritten, just NO excuse! not 27, but 24

Since I don't have coding skills, it seems the opnly viable solutuion is to build a separate generator for each frequency. "

Are you measuring output from subwoofers ?

If you are trying to get better than the pink noise method, you have to filter the input, to where it does not pick up harmnics of the frequency put into the woofer.

If the application is something else, sorry to waste your time.

but I did not notice the exact purpose of this device. Maybe you got your reasons.

Ken Knowles wrote in news: snipped-for-privacy@4ax.com:

Completely the wrong approach.

Assuming it is *ESSENTIAL* to lock the frequency to the 32768 Hz crystal, I'd start by squaring it up and doubling the frequency with a RC delay and an XOR. Then use a programmable divider chip (or rather chips as you'll probaby need to cascade them) to get pulses at a rate as close as possible to N*11.8 Hz.

Finaly a flipflop divides by two to get a good square wave.

If you dont need to start with 32768 Hz, its much more accurate if you use a significantly higher crystal frequency - at the expense of needing a longer divider chain and more bits for the division ratio to program it.

You need some way of storing the division ratio which could be programmed with a hard wired diode matrix + a 10 way rotary switch (for n=1 to 10) to ground one column at a time of the matrix, with the rows giving the binary division ratio.

Ditch the 4060, its no help at all. The oscillator can be built from the spare gates on the XOR.

However all this grief and considerable expense could be avoided if you can call in any favours to get someone to write a suitable program for a small PIC and program one for you.

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The problem is, 32 Hz has a period of 0.312500 seconds, which is

1024 'ticks' of a 32768 Hz clock. And 26.1 Hz has a period of .03831417625 seconds, which is 1255.478927.. ticks of that clock. There's no digital way to directly generate frequencies without approximations, unless the frequencies of interest line up 'just right' with your digital clock.

I hope you meant 24, not 27.

This is NOT a digital composition. A roughly square waveform may be possible that contains arbitrarily few lower harmonics (e.g., a magic sinewave approximation), but I doubt it is near trivial to compose from the source frequencies alone.

You've also suddenly changed your requirement, as I don't see how 40, 32,

24 (or 27) or 8 have anything whatsoever to do with 5.9 as a subtractive or divisive factor.

Perhaps if you could tell us a little about the underlying enigmatic purpose, we could suggest something both better suited and easier to construct.

Tim

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