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Old February 25th 04, 12:33 AM
R J Carpenter
 
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"ChipS" wrote in message
...

"W3JDR" wrote in message
...
Take a look at Analog Devices' line of DDS chips. Pretty much a one-chip
(needs ucontroller to drive it) digital solution to turn your 10MHz

clock
into virtually any frequency below 5 MHz (in theory; below 4MHz in easy
practicality). The AD9834 only consumes 20mw at 3.3 VDC. There are many
other devices in the product line. Many have built-in comparators to
produce square-wave output.


While blasts from the past, let me remind you of the CD4059 and the much
faster 74HC/HCT4059. The 74-series parts guarantee operation on inputs as
high as 20 MHz. "typically" as high as 50 MHz. These will divide by any
binary value from 3 to 2^16 or even as high as 21327 with some gaps.

The division ratio is set by 16 external pins plus some configuration pins
(24-pin DIP package).

The rub is that the part is very rare these days. I suppose discontinued.