This document describes a voice transmission system using frequency modulation for a college radio application. It includes an introduction to radio transmission and frequency modulation. The system uses a microcontroller, real-time clock, power supply, and relay to automatically control an FM radio according to a scheduled program. It allows setting time intervals to turn the radio on and off and broadcasting college programs and information through radio frequencies. The system provides an automated solution with advantages of flexibility and no human effort required.

1. PRESENTED BY
RAJESH REDDY 11X31A0435
B.NAGESH 12X31A0415
CH.SHASHANK 12X31A0422
PRAKASH 12X31A0446

2. VOICE TRANSMISSION USING
FREQUENCY MODULATION
TECHNIQUE FOR COLLEGE RADIO
APPLICATION

3. CONTENTS
 Introduction
 Existing System
 Block Diagram
 Power Supply Unit
 Working
 Advantages
 Applications
 Conclusion

4. INTRODUCTION
1. Radio is the transmission of signals through
free space by electromagnetic waves ,from
about 3 kHz to 300 GHz.
These waves are called radio waves.
2. Electromagnetic radiation travels by means of
oscillating electromagnetic fields that pass
through the air and the vacuum of space.
3.Information such as sound is carried by
systematically changing (modulating) some
property of the radiated waves such as
their amplitude, frequency, phase, or pulse width.

5. EXISTING SYSTEM
 The importance of FM radio is of course to be entertained by
listening to music and other radio programs.
 In addition, radio news and dramas can also be listened too to
stimulate our emotions and to update our knowledge about the
latest happenings.
 Through this, companies may also advertise their products and
services.
 It is also a medium of distant communication.

6. BLOCK DIAGRAM

7. RECEIVER

8. POWER SUPPLY UNIT
POWER SUPPLY UNIT

9. FM RADIO
 FM radio is used to track Radio signal.
 Radio waves are a type of electromagnetic radiation with
wavelengths in the electromagnetic spectrum longer than
infrared light. Radio waves have frequencies from 300
GHz to as low as 3 kHz, and corresponding wavelengths
from 1 millimeter to 100 kilometers. Like all other
electromagnetic waves, they travel at the speed of light.

10. REAL TIME CLOCK(DS1307)
 The RTC chip uses an internal battery that keeps the time and date
even when the power is off.

11. MICROCONTROLLER(AT89S52)
 The AT89S52 is a low-power, high-performance CMOS 8-bit
microcontroller with 8K bytes of in-system programmable
Flash memory.
 The device is manufactured using Atmel’s high-density
nonvolatile memory technology and is compatible with the
Indus-try-standard 80C51 instruction set and pinot.
 The on-chip Flash allows the program memory to be
reprogrammed in-system or by a conventional nonvolatile
memory pro-grammar.
 By combining a versatile 8-bit CPU with in-system
programmable Flash on a monolithic chip, the Atmel AT89S52
is a powerful microcontroller which provides a highly-flexible
and cost-effective solution to many embedded control
applications.

12. PIN DIAGRAM

13. FEATURES OF AT89S52
 ROM - 8K bytes
 RAM - 256 bytes
 Timer - 3
 I/O pins - 32
 Serial port - 1
 Interrupt sources - 8

14. RELAY:
A RELAY IS AN ELECTRICALLY CONTROLLABLE
SWITCH WIDELY USED IN INDUSTRIAL CONTROLS,
AUTOMOBILES, ETC…
inductor

15. LIGHT EMITTING DIODE (LED)LIGHT EMITTING DIODE (LED)
A LIGHT-EMITTING DIODE (LED) IS A SEMICONDUCTOR
LIGHT SOURCE. LED’S ARE USED AS INDICATOR LAMPS
IN MANY DEVICES, AND ARE INCREASINGLY USED FOR
LIGHTING.
k
A

16. WORKING
 Power up the entire circuit using 5V power supply unit.
• The project is specially designed to automatically switch ON the
college FM radio.
 This campus radio is run by students of college and all the
programs can listened through air.
 Bridge type full wave rectifier is used to rectify the ac out put of
secondary of 230/12V step down transformer.
 7805 Three terminal voltage regulator is used for voltage
regulation.
 This voltage supply of 5volts dc is given to the microcontroller.
 We are controlling this FM transmitter by means of a
microcontroller.
 And also we are interfacing 16x2 LCD display to the
microcontroller to I/O ports.

17.  The FM radio is interfaced to the controller
through relay by using a transistor driver circuit.
 We are using Real time clock chip DS1307 is
used to set the schedule.
 The activation and deactivation time schedules
can be programmed with microcontroller and
displayed on the lcd display.

18.  Here we are using 5 switches that switches are time interval, to
update the time fm ON, increment and decrement switches for
Increasing time, decreasing time,2 switches for setting the
Alarm.
 If FM is in ON condition at that time you can tune particular
frequency in our mobile to track the exact data.
 In this way we can design an voice transmission using
frequency modulation technique for college radio application.

19. N/C
COM
N/O
AC
230V
BULB
INDUCTOR
IRON
ARM
ON
OFF
Diagrammatic explanation:Diagrammatic explanation:

20. ADVANTAGES
 highly-flexible
 Fit & Forget System
 No need of human effort
 Easily locate different radio frequencies.
 Path Tracking
 Direction Identification

21. APPLICATIONS
 Detection and search radar
 Missile guidance systems are radar used to locate
the target of a missile. This is often present in
military aircraft.
 Radar for biological research
 Air traffic control and navigation radar
 Weather-sensing radar systems

22. CONCLUSION
 This project “Voice transmission using
frequency modulation technique for college
radio application” is designed to provide
better personal assistance depending on
user requirement. The project is been
designed and implemented with Atmel
89S52 MCU in embedded system
domain. Experimental work has been
carried out carefully.