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.

Joe
W3JDR


"Mike W" wrote in message
...
I have a need to produce an accurate 4Mhz 50% dutycycle TTL squarewave
to use as a timebase.

I have a 10Mhz IQD frequency standard of suitable accuracy. How can I
divide this to produce the 50% duty cycle 4Mhz signal?. Is it even
possible with logic alone?. I can see how to mix with either 6Mhz or
14Mhz, but this then detracts from the required accuracy.

atb Mikw