FM ICs in AM receiver

I have a ciruit diagram of an AM RECEIVER (118Mhz-136Mhz) in which the IC CA3075(FM IF AMPLIFIER LIMITER) and CA3012(FM IF WIDEBAND AMPLIFIER) are being used. I dont get it why are FM ICs being used in an AM receiver.Please help.

I think you need to show the source of the information. If you put AM through a limiting amplifier there won't be much amplitude information left!

Keith

Without referring to the specific usage of the chips in the AM receiver, the question is about meaningless. CA3075 might be e.g. used for an AFC circuit,

The CA3012 is a linear amplifier, so it can be used for any modulation. Limiting amplifiers like CA3075 are only suitable for other than AM. By the way, the frequency band 118-136 MHz is mostly used for NBFM (narrow-band FM) signals, so your receiver may not be an "AM" type.

The CA3012 data sheet I have says it is a limiting amplifier. It may be linear below the limiting voltage (around 300uV).

Keith

I agree. CA3012 cannot be used for AM demodulation at all. The only internal stage that can be used in a AM receiver is the audio preamplifier, which is available at pin 14 and pin 12.

118-136 MHz is air band (aviation communication). It's using AM, except for WX (weather information) sent as FM.

A dedicated airband transceiver or receiver will most likely have both AM and FM capability.