Phase-preserving Frequency Divider

165

01:38:42

Decelerate phase-shifted signal in order to evaluate with lower-cost components. e.g. for laser distance measurement.

Add both input signals to a slightly faster or slower frequency.
The result is an amplitude modulated harmonic, which is then rectified and smoothed.
The output has two slower frequencies with an equivalent phase shift.

https://www.youtube.com/watch?v=pcw3Ue3cLUo&t=677s
http://www.electronicdeveloper.de/FilterAktivAllPass.aspx

The left circuit is a simple phase shifter to test the devider circuit.

an other solution http://everycircuit.com/circuit/5252526659338240

published 8 years ago

zorgrian

8 years ago

Interesting! Is this easier than achieving this objective using a microcontroller?

himitsu

8 years ago

If you wanted to measure the phase shift directly, then you would need very fast and expensive electronics. However, if the signal is slowed down sufficiently, then a very favorable microcontroller, such as e.g. an ATtiny85

zorgrian

8 years ago

Yes, excellent. Then just use the microcontroller for math and UI

hurz

8 years ago

So light is traveling within 1us about 300m, which is a little to much for a distance measurement consumer tool. Anyway, lets think about 10MHz reference we go down to 100ns and 30meter distance. Lets stay at this circuit and 300m. 90kHz delta frequency make a periode of 11.1us while the reflected light compared trabels 150m and need only 1us and is still on 10% of 90kHz period. To bring that down to one meter pecision you still need to have a phase precision measurement with your Tiny85 by much less than a 1% accurate! I think its better to go to the 10MHz reference.

himitsu

8 years ago

Original were used 1,000 and 1,001 MHz, but that is the simulator too fast for you, or the simulation is so slow that you can hardly recognize anything here. A difference of 0.001 then gives a 1000 times the frequency. Here it is only about 11 times. In the end, it comes down to a compromise. The microprocessor is not that slow, but higher frequencies. The more the signal is slowed down, the closer the frequencies must be to each other and the more accurate the frequencies must be.

hurz

8 years ago

Yes the ratio of 1:1000 is hard to catch within everycircuit, or even makes no sense to try

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