Doubler circuit

[T Hergen]

Joe,

Nice simple circuits.  I was going to try the an equivalent doubler
circuit using a resistor and cap instead of flip-flops to feed the '86,
but I like your idea much better. 

One possible improvement... add another flip flop inline with the input.
The output of the first flip flop receiving the input may go meta-stable
(leading to lots of transitions on the output) if the clock goes high near
the same time as the input.  A 74175 and 74174 have 4 and 6 flip flops
respectively so the IC count won't increase.

Thanks,
Tom

On Tue, 29 Sep 1998 jdzura at csc.com wrote:

> 
> Here is a postscript file with an all digital pulse doubler. You can use GSview
> (ghost view) to look at the schematic. There are some issues, to get a non ground
> reference (AC) output, just put a cap in series with the output gate. If
> necessary, the circuit can be easily modified to generate a 50% duty cycle output
> that is not referenced to the onboard oscillator. Remember, the pulsewidth of the
> output circuit will be 1 oscillator cycle wide at a frequency of 2x the input. The
> osc can be anything you can find, we use the X043B series of canned TTL
> oscillators. They always start, regardless of temp.
> There is also a D flip flop configured for a divide by 2. (See attached file:
> P_dblr.zip)
> 
> Let me know if you have  any questions or problems
> Joe D.
> (See attached file: doubler.ZIP)
>