#### neazoi

##### Advanced Member level 6

Hi,

My application requires a about 32Hz reference oscillator (an OCXO accuracy will do), preferably square wave, but not essential.

My question is, how to derive this frequency using the less amount of components, but only using discrete components, not ICs at all (that is a requirement).

Some ideas:

1. Start with a watch crystal at 32.768kHz because these will require least stages of division. The division stages can also be discrete transistor flip flops. You will need 10 divide-by-2 stages to get from 32.878kHz down to 32Hz.

2. Another idea, to divide by a factor greater than 2 in one single stage, would be transistor phantastron divider circuits (transistor equivalent of an old valve/tube circuit). You might then only need 3 divide-by-10 circuits, instead of 10 divide-by-2 circuits.

But I cannot find any such circuits or how do they work.

3. Start off with TWO 32.768kHz oscillators and add capacitance so that one frequency is offset from the other by 32Hz. Then mix them together and select the difference frequency. I think the two-oscillators idea would have less components (just mixers, not flip-flops) but also less stability with temperature. The ppm drift of the crystals is multiplied by 1024, compared to the case where the frequency of a single crystal is divided. But if an oven is used for both oscillators, should the frequency be stable enough?

4. Any other ideas...?

My application requires a about 32Hz reference oscillator (an OCXO accuracy will do), preferably square wave, but not essential.

My question is, how to derive this frequency using the less amount of components, but only using discrete components, not ICs at all (that is a requirement).

Some ideas:

1. Start with a watch crystal at 32.768kHz because these will require least stages of division. The division stages can also be discrete transistor flip flops. You will need 10 divide-by-2 stages to get from 32.878kHz down to 32Hz.

2. Another idea, to divide by a factor greater than 2 in one single stage, would be transistor phantastron divider circuits (transistor equivalent of an old valve/tube circuit). You might then only need 3 divide-by-10 circuits, instead of 10 divide-by-2 circuits.

But I cannot find any such circuits or how do they work.

3. Start off with TWO 32.768kHz oscillators and add capacitance so that one frequency is offset from the other by 32Hz. Then mix them together and select the difference frequency. I think the two-oscillators idea would have less components (just mixers, not flip-flops) but also less stability with temperature. The ppm drift of the crystals is multiplied by 1024, compared to the case where the frequency of a single crystal is divided. But if an oven is used for both oscillators, should the frequency be stable enough?

4. Any other ideas...?

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