[time-nuts] Division Circuit

Brooke Clarke brooke at pacific.net
Fri Nov 14 23:09:50 UTC 2014


Hi:

The Twisted Johnson Ring Counter may be the one your looking for.
The individual stages are not clocked at the input frequency, but rather something like N/5.
http://en.wikipedia.org/wiki/Ring_counter#Four-bit_ring_counter_sequences
It's decodes using 2-input gates.
The last one I made used the 723 F-F from Fairchild.
http://www.prc68.com/I/comp.shtml#Lamp

Mail_Attachment --
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Tim Shoppa wrote:
> Yes! I did find a patent that illustrated the exact same feedback circuit
> as in the EE times article. But most self-decoding ring counters in
> mass-produced applications use simpler lower propagation-delay gate
> arrangements to ensure the counter self-corrects any defective sequences.
> e.g. look at how the CD4017 does not use a 10 input NAND gate!!!
>
> Tim N3QE
>
> On Fri, Nov 14, 2014 at 4:39 PM, Said Jackson via time-nuts <
> time-nuts at febo.com> wrote:
>
>> The premise of higher than "normal" click speed is false in the article
>> too because the complex NOR gate is slow with that many inputs, and its tpd
>> needs to be added to the Tsu and Tco of the flip flop chains, as well as
>> the pcb propagation delays through the worst case trace..
>>
>> It would have been faster to simply use a single reset RC delay to reset
>> all FF asynchronously while only setting one FF at the same time during
>> power-on. That would remove the Nor gate delay from the max speed
>> calculation..
>>
>> Sent From iPhone
>>
>>> On Nov 14, 2014, at 12:13, "Don Latham" <djl at montana.com> wrote:
>>>
>>> Thanks. You reminded me of the time when <design ideas> really had
>> content. No
>>> more, I'm afraid...
>>> Don
>>>
>>> Azelio Boriani
>>>> No need to digitize, the article is available here:
>>>> <
>> http://www.edn.com/design/test-and-measurement/4347165/Circuit-divides-frequency-by-N-1
>>>> or here (in .PDF):
>>>> ftp://ztchs.p.lodz.pl/PRP/PRP_2006_2007/71102di.pdf
>>>>
>>>> On Fri, Nov 14, 2014 at 8:02 AM, Perry Sandeen via time-nuts
>>>> <time-nuts at febo.com> wrote:
>>>>> List,
>>>>>
>>>>>
>>>>>
>>>>> I’ve digitized and edited an article titled* Circuit DividesFrequency
>> by N+1
>>>>> by Bert Erickson, Fayetteville, NY from EDN 7/11/2002*.
>>>>>
>>>>>
>>>>>
>>>>> Essentially, this circuit is expandable and allows for adivision by any
>>>>> number plus one.
>>>>>
>>>>>
>>>>>
>>>>> Anyone who wants a PDF copy please send me an original emailoff list.
>>>>>
>>>>>
>>>>>
>>>>> Regards,
>>>>>
>>>>>
>>>>>
>>>>> Perrier
>>>>>
>>>>>
>>>>> _______________________________________________
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>>>
>>> --
>>> "The power of accurate observation is commonly called cynicism by those
>> who
>>> have not got it."
>>> -George Bernard Shaw
>>>
>>> Dr. Don Latham AJ7LL
>>> Six Mile Systems LLC
>>> 17850 Six Mile Road
>>> Huson, MT, 59846
>>> mail:  POBox 404
>>> Frenchtown MT 59834-0404
>>> VOX 406-626-4304
>>> Skype: buffler2
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>>>
>>>
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