Controlling a 2 Gate Oscillator

At the very least, it sounds like you need a frequency comparison, which means sequential logic. An AND or XOR gate makes a basic phase detector (good for 180 degrees), and a flip-flop (fed runt trigger pulses) makes an even better one.

If you're keen, you might do it within a cycle. If you're not (or it doesn't matter much), you can filter it and do analog comparison. Or use F-V converters or something.

Tim

-- Deep Fryer: A very philosophical monk. Website @

That's something to think about. Thanks..

It's one of those electronics problems where just defining the problem is a problem :P

D from BC

Welll..Not too much SED interest on this item ... :( Too homeworkish I suppose..

I figured it out (or I'm very close)...and it took me all freakn day :( Only uses 1 schmitt NAND gates, 1 resistor and 1 capacitor.

One NAND schmitt gate is configured as a hysteretic oscillator. The control signal G connects to one of that gate inputs. The result is inverted but that's easy to fix. I'm checking it out with spice.

By the way... I goofed with the classic osc schematic..forgot one R

Also note...this circuit may not oscillate. 3 gates are needed for assured oscillation.

I used neither config.. Instead, used a single gate oscillator.

D from BC