FM RECEIVER
A presentation on simulating and
implementing
an FM Receiver circuit by Group-B.
Department of EEE
L2-T2, Sec: C
Daffodil International University
INTRODUCTION
An FM receiver is an electronic device designed to capture
and process radio waves carrying FM (Frequency
Modulation) broadcasts. Here's a technical breakdown:
Function:
• Picks up radio waves with an antenna.
• Isolates the desired FM broadcast signal from others
using filters.
• Amplifies the weak signal for further processing.
• Demodulates the FM signal to recover the original audio
information.
METHODOLOGY
• Hardware
Implementation.
• Simulation in Software.
COMPONENTS
Components used in this project:
• Transistor BF494/2N3904 (2)
• Trimmer Capacitor 1-22pF
• Capacitor 0.22uF
• Capacitor 0.1uF
• LM 386 IC
• Inductor 4 turn
• Resistor 22k
• Potentiometer 10k
• Speaker
AMPLIFIER
LOCAL OSCILLATOR
OSCILLATOR WORKING
• The LC tank oscillator utilizes the opposing properties of
a capacitor (C) and inductor (L) to create sustained
oscillations at a specific frequency.
The Oscillation:
1.Charged capacitor (C) discharges through L, creating
current flow.
2.L builds a magnetic field opposing the current change.
3.When C is discharged, the collapsing magnetic field
induces a voltage, charging C in the opposite polarity.
4.The cycle repeats, resulting in continuous oscillation at a
frequency determined by L and C:
f = 1 / (2π√(LC))
BLOCK DIAGRAM
BASIC WORKING PRINCIPLE:
An FM receiver consists of several stages:
1.RF (Radio Frequency) Stage: The antenna captures radio
waves and the tuner circuit selects the desired FM broadcast
frequency.
2.IF (Intermediate Frequency) Stage: The selected signal is
converted to a fixed intermediate frequency for further
amplification.
3.Demodulating Stage: Recovers the original audio information
by demodulating the FM signal (extracting the changes in
frequency).
4.Audio Amplifier Stage: Amplifies the recovered audio signal for
playback through speakers.
CIRCUIT DIAGRAM
BREADBOARD IMPLEMENTATION
SIMULATION
BENEFITS & APPLICATIONS
• Frequency modulation can be used for the broadcasting of FM radio.
This helps in larger signal to noise ratio.
• Telemetry, radar and seismic prospecting, EEG monitoring of
newborns etc also use the technique of frequency modulation.
• It is also used in music synthesis, some systems that use video-
transmission and also for magnetic tape-recording systems.
ADVANTAGES OF FM
• Frequency modulation is resilient to signal level variations. Any
variation in signal level does not affect the output as long as the
receiver is able to cope up with the signal level. This makes the FM
ideal for two-way radio communication or mobile communication
application.
• Frequency modulation is also resilient to noise and interference.
• It is also easier to apply modulation at a low level power stage of a
transmitter.
• With the help of frequency modulated signals, we can use RF
amplifiers.
CONCLUSION
• This is a simplified overview. FM receivers can be
complex electronic devices, but the core principle
remains the same - capturing, processing, and delivering
audio information transmitted over radio waves using
frequency modulation.
