Rookie Frequency Divider Question

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Engineer1138
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Post by Engineer1138 » Wed Apr 25, 2007 12:12 pm

Since the goal is to multiply the input by 5/8, I'd use an AVR processor and a state machine.
STATE PULSES_IN PULSES_OUT
0 2 1
1 2 1
2 2 1
3 2 2
0 2 1
...

This can be simplified, but that's the basic method.The end goal is to output 5 pulses for every 8 input.

A more sophisticated approach, which will result in smoother output pulses with constant spacing (unlike the above), is to do a software PLL where the output frequency is 5/8ths the input.

VIRAND
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Post by VIRAND » Wed Apr 25, 2007 1:12 pm

In other words:

STATE 0 --- 1 --- 2 --- 3
IN- 0101 0101 0101 0101
OUT 0100 0100 0101 0100

IN WAVE _/\_/\_/\_/\_/\_/\_/\_/\
OUT WAVE _/\___/\___/\_/\_/\__

Looks funny but might work.

Gorgon
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Post by Gorgon » Mon Apr 30, 2007 5:46 am

You could also solve this with an old eprom and a binary counter. Make a sequence 1609 cycles long and program the eprom to let out 1000 cycles during this sequence and use oneof the outputs to reset the counter on the correct number of cycles. This way you increase the accuracy too.

TOK ;)
Gorgon the Caretaker - Character in a childrens TV-show from 1968. ;)

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