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Author Topic: what LPF circuit to use for FM MPX decoder IC output  (Read 550 times)

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Offline ELS122Topic starter

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what LPF circuit to use for FM MPX decoder IC output
« on: January 11, 2022, 12:21:53 pm »
so I'm fixing a radio that isnt broken (trying to improve it),  ;D and I pointed my attention to the LPF of the FM Multiplex decoder IC (which is a KA2263), and since I did a dumb thing and just removed it entirely, I dont know what it was,
the datasheet says I need to also filter out 18khz... why?
and if so, can't I somehow mix in a 18khz signal from the IC instead? in the opposite phase?

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Offline bob91343

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Re: what LPF circuit to use for FM MPX decoder IC output
« Reply #1 on: January 11, 2022, 06:05:32 pm »
You need a diagram and parts list.
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Offline ELS122Topic starter

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Re: what LPF circuit to use for FM MPX decoder IC output
« Reply #2 on: January 12, 2022, 10:50:58 am »
a diagram for something I'm asking for a diagram for?
« Last Edit: January 12, 2022, 10:58:55 am by ELS122 »
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Offline jonpaul

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Re: what LPF circuit to use for FM MPX decoder IC output
« Reply #3 on: January 12, 2022, 11:12:00 am »
18 kHz LPF removes 38 kHz sidebands of FM stereo composite signal.

These are common parts from Murata, TDK, etc.

Search"18kHz FM streo filter"

j



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Jean-Paul  the Internet Dinosaur
 
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