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Old 26th May 2021, 5:38 am   #12
Join Date: Apr 2017
Location: Buderim, Queensland, Australia.
Posts: 370
Default Re: 1MHz output impedance query?

If you are using an LC RF Filter for square to sine conversion, can I suggest you use an online calculator.

Sample filter circuit for your situation attached.

This was calculated with RF Tools "LC Filter Design Tool".

I checked the sample circuit with the SimSmith analyser program to be OK, but values can be slightly optimised.

If you go ahead with this and have difficulty with making or testing the inductors, I can make them up for you and post them off FOC.
If you make a different design with different values, I can check the circuit then make up the inductors and post them off.
You may need to tell us the circuitry immediately before and after the filter, so I can adjust the filter source and load impedances for a final design.

If you make up the inductors yourself, I suggest using type 61 ferrite cores in 50 size (one half inch). The core may be marked "FT50-61".

I have not gone into some filter aspects deliberately, but you are in the right forum to ask questions, even very difficult (radio) ones.
I may not be the one to answer however.

Good luck
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