[time-nuts] reference oscillator input circuit
jimlux at earthlink.net
Wed Dec 8 13:09:24 EST 2010
Rick Karlquist wrote:
> jimlux wrote:
>> I'm looking for suggestions on a general circuit that can be used to
>> receive an external frequency reference (nominally a real clean sine
>> wave at, say, 10 MHz, although up to 100 MHz is possible) and turn it
>> into a "real clean" square wave. Galvanic isolation is a plus (a
>> transformer or capacitor would probably do that).
> In the 5071A at 80 MHz, we capacitively coupled a sine wave into
> a 74AC series logic gate, that had DC bias resistors to hold
> it at half the supply voltage.
that's similar to what Said recommended last year.. he uses a big
resistor from output to input to set the bias, rather than a divider.
More information about the time-nuts