[sdiy] frequency counter

[Scott Gravenhorst]

mark verbos <mverbos at earthlink.net> wrote:
>How do you ddivide by 25,000? Aren't all counters powers of 2?

There are circuits that can divide by numbers other than powers of 2.  I
figured out a circuit for a symmetrical output divide by 3.  For 25,000, you
will need divide by 5 and divide by 2 as they are the two prime factors of
25,000.  Ring counters are one way, JK flip flops with special logic
interconnections is another.  

I wouldn't mind knowing of a reference of different non-binary power counter
circuits, especially ones with symmetrical outputs.

>Mark
>
>
>
>Magnus Danielson wrote:
>
>>From: mark verbos <mverbos at earthlink.net>
>>Subject: Re: [sdiy] frequency counter
>>Date: Sat, 26 Jun 2004 21:22:36 -0400
>>Message-ID: <40DE215C.3000700 at earthlink.net>
>>
>>  
>>
>>>Ian Fritz wrote:
>>>
>>>    
>>>
>>>>Sure.  When I set up a patch for recording I just zero-beat the VCOs 
>>>>in against my xtal-derived A440.  And since I have carefully taken out 
>>>>all the drift in my VCOs I never have to touch the tuning again 
>>>>(although I can't help checking once in a while, anyway).
>>>>      
>>>>
>>>What crystal frequency did you use to get an A440?
>>>    
>>>
>>
>>I was thinking the same thing.
>>
>>  
>>
>>>I have been tinking about this over the last week and haven't seen any that
>>>seemed right for it.
>>>    
>>>
>>
>>However, I came to realize that 11 MHz isn't that unusual. Just divide by
>>25000 and you are home free!
>>
>>Cheers,
>>Magnus
>>
>>  
>>
>

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