### Author Topic: RF frequency divider  (Read 1064 times)

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#### Sariel

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##### RF frequency divider
« on: August 09, 2024, 03:01:22 pm »
Hey,

I am looking for some material:
Schematic, book chapter,good practical paper about how to build a RF frequency divider.

It is easy to divide frequency in digital electronics for rectangular waveform. But I want to build a circuit to divide the frequency (without doing downconversion using a mixer). Just an opposite circuit to the typical multiplier circuit.

I would probably try this first in the VHF band, as parasitic will be easier to overcome and measurements easy to conduct.

#### szoftveres

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##### Re: RF frequency divider
« Reply #1 on: August 09, 2024, 03:17:17 pm »

#### vk4ffab

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##### Re: RF frequency divider
« Reply #2 on: August 09, 2024, 10:04:15 pm »
Hey,

I am looking for some material:
Schematic, book chapter,good practical paper about how to build a RF frequency divider.

It is easy to divide frequency in digital electronics for rectangular waveform. But I want to build a circuit to divide the frequency (without doing downconversion using a mixer). Just an opposite circuit to the typical multiplier circuit.

I would probably try this first in the VHF band, as parasitic will be easier to overcome and measurements easy to conduct.

depending on the resolution you want, you can divide by 2, 4 etc by using a couple of flip flops, you can use a PLL or there are dedicated divider IC's which are just a selection of gates and flip flops you can switch on and off like the SN74LS29. Drop your design frequency a lot and you can do frequency division with a 555 IC. The what and how depends on your application, but, with a single D flip flop IC you should be able to divide up your VHF input to something much smaller in about 5 mins on a bread board. Its the heart of a lot of home brew receivers needing a quadrature IF.

https://www.electronics-tutorials.ws/counter/count_1.html
« Last Edit: August 09, 2024, 10:07:06 pm by vk4ffab »

#### RFDx

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##### Re: RF frequency divider
« Reply #3 on: August 10, 2024, 10:34:00 am »
But I want to build a circuit to divide the frequency (without doing downconversion using a mixer). Just an opposite circuit to the typical multiplier circuit.

Search for "regenerative frequency divider". A few examples:

http://www.ke5fx.com/regen.htm
https://tf.nist.gov/general/pdf/2609.pdf
https://csaavedra.net/papers/conferences/2011-NORCHIP-divide-by-3.pdf
https://ieeexplore.ieee.org/document/6243683

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#### 807

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##### Re: RF frequency divider
« Reply #4 on: August 11, 2024, 12:18:56 pm »
Are you looking to just halve the frequency, or do you want to divide by 4, 8, 16 etc. or divide by some odd numbers?

#### Sariel

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##### Re: RF frequency divider
« Reply #5 on: August 11, 2024, 03:07:55 pm »
I am looking both for odd and even divisions.

#### Sariel

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##### Re: RF frequency divider
« Reply #6 on: August 11, 2024, 03:10:16 pm »
This is probably the circuit.

How popular and used is this method?
Are such circuits used as prescalers in commercial test equipment?

Can such circuits be simulated in ADS, just by using s paramters? Frequency domain? Or time domain simulations are needed to simulate correctly the feedback loop?

#### EggertEnjoyer123

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##### Re: RF frequency divider
« Reply #7 on: August 12, 2024, 08:37:50 pm »
This is probably the circuit.

How popular and used is this method?
Are such circuits used as prescalers in commercial test equipment?

Can such circuits be simulated in ADS, just by using s paramters? Frequency domain? Or time domain simulations are needed to simulate correctly the feedback loop?
You can't use S parameters because the transistors are behaving very non-linearly. You can tell because new frequencies are being generated (specifically half the input frequency), while with S parameters we assume that everything is linear and no new frequencies are created. You will have to do time domain simulation.

Is there a reason why the MC12093 (or something similar) won't work?

Smf