If I use a CD 4060 to generate 137 Hz, given the divide down outputs available, what frequency crystal should I use?
I am not aware of what crystals are commonly available, so my mind is buckling trying to find a starting point.
Perhaps someone here is more familliar with this procedure and would be so kind as to offer advice.
Don Lerner
Just how accurate does it need to be?
Join the 21st century and use a microcontroller.
I would use a microcontroller for this. There are some small, inexpensive 8-pin devices out there that have internal clocks and counters. For example, this one should do nicely: Link:
It has an internal 7.373 MHz oscillator, or you can use an external crystal (from 20 kHz to 12 MHz). Just use software to count it down. Should be relatively easy to get
137 Hz out on a port pin.If you are not terribly familiar with uPC's, this sound like the PERFECT project to learn about them!! It doesn't get too much easier than this.
Good luck with your project!!
-mpm
As the other posters said a uC is the better choice here. If it absolutely has to be the 4060 the procedure goes like this:
Let Excel display a (2^x)*137 ladder of values, then see if any one comes close to a standard crystal. The only one I could see would be the former European chroma carrier frequency of 4.43MHz but you'd need
4.49MHz. Not easy to pull a crystal that far, it's more than a percent. I don't think this is really going to work with a crystal unless you use a uC, or the timer in there in particular.-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Of course you can get programmable XOs, programmed by the distributor, for a few bucks, at any frequency you like.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
As Joerg has pointed out, a straight divide by 2^n approach isn't too promising.
Throw in a 74HC40103 programmable 8-bit down-counter (or two) - which can divided by any number from 255 down, and you should be able to get pretty close.
-- Bill Sloman, Nijmegen
A 560kHz ceramic resonator seems to be commonly available. Dividing by 4096 (12 stages) gives you 136.71875Hz. I don't know if you can push it to 561.152kHz to get an exact 137Hz.
Or, if you're not firmly committed to using a 4060, you can use a CD4059 presettable counter to get 137Hz from just about any crystal (within reason of course). That includes a common
32.768kHz watch crystal divided by 239, the ubiquitous 455kHz resonator divided by 3321, 1MHz/7299 and so on.
I would second this -- it's a very good, fast, and inexpensive way to go. The only caveat is that these scillators are usually targeted towards digital applications, so their phase noise tends to be rather poor; just something to be aware of if it matters in your application.
But that's like ordering take-out pizza.
We always make our own from scratch, including dough and all :-)
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
Hey, how's the ticker doing? Much better than before the new valve?
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
So far the OP hasn't come back to clarify one vital point: whether he's simply looking for a way to generate 137Hz pulses or, for some reason, he wants to do it with a crystal and a CD4060. Neither has he given any indication of the degree of precision and stability he needs.
... but what noise does your pizza make when it's toasted?
-- Thanks, Fred.
Real men don't toast pizza, they bake it over a wood or charcoal fire, beer in hand :-)
BTW, we sometimes bake bread that way. It's so good you can't stop eating. Now if we just had your Camembert cheeses ...
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
That's just because you live in the boonies and don't know any better.
Me, I'm 2 blocks from Dom & Vinnie's. New York pizza doesn't get any better.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
s
-...
You can always get a custom crystal made if this is just a one off project. I had one made, but I found an off the shelf job that would work. I had a custom crystal cut for $18. I had the guy call back with the order, he said it would take a couple of days, but it took weeks. I had already redesigned the thing and moved on.
Regards, Chris
-- If you were to use all 14 stages, 1.122304 MHz, and for every stage shorter than 14, the frequency would drop by a factor of 2.
What is the 137Hz related to?
I know 24Hz and 25Hz are film related.
50Hz and 60Hz are AC line related.I would just program a uC for 24,25,50,60,100,120 and 137, using a 4 bits input selector. Anyone wants it for $1?
On Wed, 10 Mar 2010 18:12:01 -0600, John Fields wrote:>
3905JF
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