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donnie
Joined: 13 Nov 2003
Posts: 12
Location: Kissimmee Florida
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| Prescaler /256 |
 Posted: Wed Jun 23, 2004 9:31 am |
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I see that you can make a 50mhz frequency counter using a pic chip. Is it possible to do a /256 calc on the input code to allow it to count to 1 Ghz?
I know i can use a prescaler like a SAB6456 to divide it down.
Were 50 mhz to 1ghz in is scaled to 0-50mhz on the display.
Thanks,
Donnie |
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Neutone
Joined: 08 Sep 2003
Posts: 839
Location: Houston
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| Re: Prescaler /256 |
| Posted: Wed Jun 23, 2004 10:00 am |
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| donnie wrote: | I see that you can make a 50mhz frequency counter using a pic chip. Is it possible to do a /256 calc on the input code to allow it to count to 1 Ghz?
I know i can use a prescaler like a SAB6456 to divide it down.
Were 50 mhz to 1ghz in is scaled to 0-50mhz on the display.
Thanks,
Donnie |
There is a limit to how fast the timer can be incremented. You can do a divide by 256 but that does not effect the limit on the pulse rate on the input pin. The prescaler is a part of the timer and has the same limit on speed of operation. |
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donnie
Joined: 13 Nov 2003
Posts: 12
Location: Kissimmee Florida
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| Posted: Wed Jun 23, 2004 10:38 am |
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Thanks for the info.
Iam going to use the HMC394LP4 programmable divider chip.
With a divide by 20 1ghz in will equal 50 mhz out and will even do divide by 32.
Thnaks,
Donnie |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Wed Jun 23, 2004 4:24 pm |
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Hi donnie,
Yes of course you can use the SAB6456 as external prescaler
dividing by 256, will output 3,906Mhz with 1Ghz input.
Then itīs a matter of math to display the real frequency.
Humberto |
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