Description
This is the most simple fm receiver with good performances that works
great even if the sensitivity is not too high. The working principle of
this fm receiver may seem a little unusual. It is made of an oscillator
(T2 and T3) that is synchronized with the received frequency of T1.
This transistor works as a broadband preamplifier in VHF range.
This transistor works as a broadband preamplifier in VHF range.
The oscillator is adjusted between 87 … 108 MHz with C5. Because of the
synchronization, the oscillator output will have the same frequency
deviation as the received signal from the fm antenna. This deviations
are caused by the broadcasted audio informations. The frequency
modulated signal show up on P1 + R5. Low pass filter R6/C6 extracts the
audio signal and then is amplifier by T4 … T6 and transmitted at the
output through C9 capacitor.
Circuit Diagram
The coil details are presented in the fm receiver circuit diagram. The
radio receiver is adjusted on different stations with the help of C5. P1
potentiometer is adjusted untill the best reception is obtained. If we
attach an audio amplifier and a speaker then this fm receiver can be
made very compact as a pocket radio.
+ comments + 2 comments
what is the value of L1,L2,L3?
IN H?
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