A Project Report ON F.M JAMMER. Submitted By: in partial fulfillment for the award of the Degree of Bachelor of Technology

Transcription

1 A Project Report ON F.M JAMMER Submitted in partial fulfillment for the award of the Degree of Bachelor of Technology In Department of Electronic instrumentation & control Engineering Project Guide Submitted By: Mr. Rahul Tyagi Dharmesh kumar Asst. Prof.-ECE/EIC Raju Sharma Satish Department of Electronic instrumentation & control Engineering St. Margaret Engineering College, Neemrana Rajasthan Technical University, Kota November if you faced any problem on this project i ll help u 1

2 Department of Electronic instrumentation&control Engineering St. Margaret Engineering College Neemrana, NH-8, Alwar, Rajasthan CERTIFICATE This is to certify that the project titled F.M JAMMER submitted by Dharmesh kumar Gautam (08ESMEI013), Raju Sharma(08ESMSI043), Satish Babu(08ESMEI047) in partial fulfillment of the course work requirement for B.Tech. Program in the Department of Electronic instrumentation & control Engineering, St. Margaret Engineering College Neemrana is a bonafide work carried out by him under my guidance and supervision. This project report has been find quite satisfactory. Head of Department Project Guide Name Vinith Chouhan Head of Dept.-ECE/EIC Department of ECE/EIC Engineering St. Margaret Engineering College Neemrana Mr. Rahul Tyagi Asst. Prof. - ECE/EIC Department of ECE/EIC Engineering St. Margaret Engineering College Neemrana 2

3 ACKNOLEDGEMENT This project is indeed first of its kind of practical exposure offered to us and we must first acknowledge to our college and university for facilitating us such a tremendous experience. Our sincere obligation extends to our project guide Mr. Rahul Tyagi who helped us to make this project a success. The guidance enhanced the subject knowledge and encouraged us to a great extent. Special thanks to our project lab assistant Mr. surender Kumar for his sincere efforts for us. Throughout the project work his support and guidance helped us a lot for the partial fulfillment. This work would not have been possible without the encouragement and able guidance of our project incharge Mr. P.K. Nathaney and the entire faculty member. Their enthusiasm and optimism made this experience both rewarding and enjoyable. Most of the novel ideas and solutions found in this project are the result of their numerous stimulating ideas. Their feedback and editorial comments were also invaluable for the writing of this thesis. We would like to express our deep sense of gratitude towards the head of department of electronics for his constant source of inspiration for me throughout this work We would also hearty thanks to all our college guies and friends who have given us a indelible memories of working together. Their cooperation was simply awesome and instilled with us forever. Dharmesh kumar(08esmei013) Raju Sharma(08ESMSI043) Satish(08ESMEI047) 3

4 ACKNOWLEDGEMENT We would like to express our deep sense of gratitude to our project guide, Mr.Rahul Tyagi for encouraging us to undertake this project as well as providing all the necessary guidance and inspirational support throughout this project. We deem it our privilege to have carried this project under his valuable guidance. We are also grateful to other faculty members of our department, who has constantly watched us and helped us in times of need. We are also indebted to our friends for always being there with all their help and support. `` FM TRANSMITTER AS A JAMMER 4

5 Contents ABSTRECT PAGE NO. CHAPTER 1 Introduction : 8 CHAPTER 2 Terminology Used: 9 CHAPTER 3 History associated with Jamming: 10 CHAPTER 4 Fm Transmitter as Jammer (Methodology): Overview: 4.2 Modulation: 4.3 Colpitt Oscillator: 4.4 Signal Generation and Amplification: 4.5 Buffer: 4.6 Transmitter: 4.7 Capture Effect CHAPTER 5 Circuit Diagram: 15 CHAPTER 6 16 Principle of operation: 5

6 CHAPTER 7 19 Radio: CHAPTER 8 20 Discription of component used: CHAPTER What have we done: CHAPTER Result: CHAPTER Applications CHAPTER Appendices 12.1 TRAI 12.2 Data Sheet of LM 358 CHAPTER Bibliography: Conclusion 36 6

7 ABSTRACT Cell phones and radio receivers are used everywhere these days. It's great to be able to call anyone anytime. But unfortunately, restaurants, movie theatres, concerts, shopping malls and churches all suffer from the spread of cell phones because not all cell-phone users know when to stop talking. While most of us just grumble and move on, some people are actually going to extremes to retaliate. FM Jammer can be one of the solutions to this problem. A transmitter is a device from which signal is transmitted into free space, after insertion of suitable carrier, i.e. is superimposed on a high frequency-sine wave. In Frequency Modulation, frequency of carrier is varied according to the modulating signal. The capture effect, or FM capture effect, is a phenomenon associated with FM reception in which only the stronger of two signals at, or near, the same frequency will be demodulated. It is defined as the complete suppression of the weaker signal at the receiver limiter (if it has one) where the weaker signal is not amplified, but attenuated. We are using this principle here to make a Jammer out of the FM transmitter. Major application of Jammer includes in controlling a hostage situation in which police can control when and where a captor can make a phone call. Police can block phone calls during a drug raid so suspects can't communicate outside the area. Cell-phone jammers can be used in areas where radio transmissions are dangerous, (areas with a potentially explosive atmosphere), such as chemical storage facilities or grain elevators. 7

8 CHAPTER :-1 INTRODUCTION Cell phones are used everywhere these days. According to the Telecom Regulatory Authority of India (TRAI), almost million people were subscribers of Mobile phones at the end of This is likely to increase to more than 500 million mobile phone users by 2010 according to a survey conducted by Nokia. [1] It's great to be able to call anyone at anytime. Unfortunately, restaurants, colleges, Hospitals, shopping malls and churches all suffer from the spread of cell phones because not all cell-phone users know when to stop talking. There comes the need of jamming which is nothing but blocking the signals. On one hand, jamming is seen as property theft, because a private company has purchased the rights to the radio spectrum, and jamming the spectrum is akin to stealing the property the company has purchased. It also represents a safety hazard because jamming blocks all calls in the area, not just the annoying ones. Jamming a signal could block the call of a babysitter frantically trying to contact a parent or someone trying to call for an ambulance. While on the other hand it is a very handy tool to curb in the theft/emergencies like bomb tracing (where usually cell phone communication is used) by controlling a hostage situation in which police can control when and where a captor can make a phone call. Police can block phone calls during a drug raid so suspects can't communicate outside the area FM in terms of noise rejection and co-channel (or adjacent channel interference). If two signals of same frequency (or within some deviation), the signal with the lower amplitude is attenuated with the factor of the amplitude of that having higher amplitude and the other remains unaffected. We are using this property to model this Jammer, which is known as capture effect. We have four major be converting speech signal to some voltage level and its amplification is done using OPAMP 8

9 (LM-358). Then with the help of buffer which is basically a voltage follower we give this signal to oscillator. Clapped oscillator modifies its frequency according to incoming signal given, thus modulation of frequency takes place in this stage. Finally this signal is transmitted through antenna of proper dimensions. It is said that science is a both boon and bane. It all depends upon the person who regular regulation and monitoring by the government in accordance with very strict guidelines to prevent any misuse arising from a jammer. CHAPTER:-2 TERMINOLOGY USED 1. Signal: In the physical world, any quantity measurable through time or over space can be taken as a signal. 2. Baseband Signal: Baseband signal refers to the message signals (Modulating signal) which are to be transmitted over long distances using suitable techniques. 3. Carrier: Carrier is a high frequency signal which is used for long distance transmission of low-frequency message signals. 4. Modulation: Modulation is defined as the superposition of a modulating signal over high frequency carrier signal so as to change the characteristics of the carrier wave according to the modulating signal. 5. FM Modulation: In Frequency Modulation, the frequency of carrier is varied by modulating voltage whose amplitude remains constant. 6. Transmitter: Transmitter as a whole refers to that block which consists of encoder, modulator and transmitting antennae in which a signal is converted into radio waves. 7. Oscillator: Oscillator is an instrument that generates repetitive alternating current/voltage waveform of fixed amplitude and frequency without any external input signal. 8. Voltage Controlled Oscillator: In a Voltage Controlled Oscillator, external input signal decides the frequency of oscillator. Frequency increase for positive input voltage and decreases for negative input voltage. 9. Amplifier: Amplifier is a device which boosts the input signal in parameters of either current or voltage. 9

10 10. Buffer: A Buffer is the one that provides the impedance transformation from one circuit to another. 11. Capture Effect: The capture effect is defined as the complete suppression of the weaker signal at the receiver limiter (if it has one) where the weaker signal is not amplified, but attenuated. 12. Bandwidth: It s the difference between the maximum and the minimum frequency component contained in a signal. CHAPTER:-3 HISTORY ASSOCIATED WITH JAMMING: During World War II ground radio operators would attempt to mislead pilots by false instructions in their own language, in what was more precisely a spoofing attack than jamming. Radar jamming is also important to disrupt use of radar used to guide an enemy's missiles or aircraft. Modern secure communication techniques use such methods as spread spectrum modulation to resist the deleterious effects of jamming. Jamming of foreign radio broadcast stations has often been used in wartime (and during periods of tense international relations) to prevent or deter citizens from listening to broadcasts from enemy countries. However such jamming is usually of limited effectiveness because the affected stations usually change frequencies, put on additional frequencies and/or increase transmission power. 10

11 CHAPTER:-4 FM Transmitter as Jammer (Methodology) 4.1 Modulation: Modulation is defined as the superposition of a modulating signal over high frequency carrier signal so as to change the characteristics of the carrier wave according to the modulating signal. In Frequency Modulation, the frequency of carrier is varied by modulating voltage whose amplitude remains constant. In other words argument of carrier is varied according to modulating signal. Mathematically, let m(t) be the modulating signal and v(t) be the carrier signal such that m(t)= A cos ( wmt ) and v(t)= V cos ( wct + ø ). Then modulated signal x(t)= V cos ( wct + Ɵ(t) ) where Ɵ(t)= Kf ʃ m(t) dt. Simply if Wx(t), is the frequency of modulated signal, it varies as Wx(t) = wc + Kf wm Oscillator is an instrument that generates repetitive alternating current/voltage waveform of fixed amplitude and frequency without any external input signal. In a Voltage Controlled Oscillator, external input signal decides the frequency of oscillator. Frequency increases for positive input voltage and decreases for negative input voltage. So if modulating signal is applied to the input of VCO, the output of Oscillator will have a varying frequency signal which is nothing but the frequency modulated signal. 4.2 Colpitt Oscillator: A crystal Oscillator provides constant stable frequency at higher frequencies but we cannot vary the frequency by applying input bias voltage or simply it cannot act as a VCO. A colpitt oscillator provides relatively stable frequencies in which the output frequency can be obtained as a simple function of modulating voltage. A Colpitts oscillator is one of a number of designs for electronic oscillator circuits using the combination of an inductance (L) with a capacitor (C) for 11

12 frequency determination, thus also called LC oscillator. The basic Colpitts circuit has two capacitors and one inductor to determine the frequency of oscillation. The feedback needed for oscillation is taken from a voltage divider made by the two capacitors. As with any oscillator, the amplification of the active component should be marginally larger than the attenuation of the capacitive voltage divider, to obtain stable operation. Thus, using the Colpitts oscillator for a variable frequency oscillator VFO is best done by using a variable inductance for tuning, instead of tuning one of the two capacitors. If tuning by a variable capacitor is needed, it should be a third one connected in parallel to the inductor (or in series as in the Clapp oscillator). Here base of transistor is grounded, that implies the frequency of oscillator is constant. If some input is applied to this frequency will increase or decrease depending upon the amplitude of bias applied is positive or negative. Moreover this deviation in frequency is proportional to the amplitude of bias. Thus if modulating signal is applied to this base, output of the oscillator will be a frequency modulation signal. General diagram of colpitt oscillator is given below: 12

13 Figure of colppt oscillator 4.4 Signal Generation and Amplification: A mike (or mic ) is used to generate signal from audio signal. Some other signal generator with high Bandwidth could be used if we are to cover the maximum of BW of a signal that we intend to block. This signal is very week so it needs to be amplified. An operational amplifier has a very high gain which can be used to amplifying such weak signal. We have used here LM 358 which has a high gain Oscillation Frequency is given by: where C = Series comination of C1 and C2 Or, and has internally frequency compensated operational amplifiers which are designed specifically to operate from a single power supply over a wide range of voltages. [5] We are using LM 358 as non-inverting amplifier. Further to reduce the effect of noise and stabilize the circuit we are using voltage divider circuit at input. 13

14 4.5 Buffer: Voltage follower is used as buffer here. Voltage follower used here is a simple unity gain amplifier realised with same LM 358 operational amplifiers. This is used to match the impedance transformation from one circuit to another. 4.6 Transmitter: A transmitter is an electronic device which, usually with the aid of an antenna, propagates an electromagnetic signal such as radio, television, or other telecommunications. Generally in communication and information processing, a transmitter is any object (source) which sends information to an observer (receiver). When used in this more general sense, vocal chords may also be considered an example of a transmitter. In radio electronics and broadcasting, a transmitter usually has a power supply, an oscillator, a modulator, and amplifiers for audio frequency (AF) and radio frequency (RF). The modulator is the device which piggybacks (or modulates) the signal information onto the carrier frequency, which is then broadcast. Size of transmitting antenna should be comparable to that of wavelength of signal. Mathematically, size of antenna L= α/4; where α is the wavelength of signal. Wavelength of the signal used is related to its frequency f by α = c/f where c is velocity of light in vacuum. Therefore, L = α/4f; 4.7 Capture Effect: In telecommunication, the capture effect, or FM capture effect, is a phenomenon associated with FM reception in which only the stronger of two signals at, or near, the same frequency will be demodulated. The capture effect is defined as the complete suppression of the weaker signal at the receiver limiter (if it has one) where the weaker signal is not amplified, but attenuated. When both signals are nearly equal in strength, or are fading independently, the receiver may switch from one to the other and exhibit picket fencing. The capture effect can occur at the signal limiter, or in the demodulation stage, for circuits that do not require a signal limiter. Some types of radio receiver circuits have a stronger capture effect than others. The measurement of how well a receiver can reject a second signal on the same frequency is called the capture ratio for a specific receiver. It is measured as the lowest ratio of the power of two signals that will result in the suppression of the smaller signal. A1 cos ( wct + ø(t) ) A2/A1 cos ( wct + ø(t) ) A1 cos ( wct 14

15 + ø(t) ) A2 cos ( wct + ø(t) ) If amplitude A1> A2, the signal received at the receiver due to FM2 is attenuated by a factor of A1. Therefore, signal due to FM2 will be A2/ A1 cos ( wct + ø(t) ). CHAPTER:-5 CIRCUIT DIAGRAM OF FM 1 FM 2 RECEIVER: CIRCUIT DIAGRAM OF FM 1 FM 2 RECEIVER: 15

16 CHAPTER:-6 PRINCIPLE OF OPERATION:RADIATION OF ELECTROMAGNETIC ENERGY The electromagnetic radiation from an antenna is made up of two components, the E field and the H field. We discussed these fields in chapters 1 and 2. The two fields occur 90 degrees out of phase with each other. These fields add and produce a single electromagnetic field. The total energy in the radiated wave remains constant in space except for some absorption of energy by the Earth. However, as the wave advances, the energy spreads out over a greater area and, at any given point, decreases as the distance increases. Various factors in the antenna circuit affect the radiation of these waves. In figure, for example, if an alternating current is applied at the end of the length of wire from A to B, the wave will travel along the wire until it reaches the B end. Since the B end is free, an open circuit exists and the wave cannot travel farther. This is a point of high impedance. The wave bounces back (reflects) from this point of high impedance and travels toward the starting point, where it is again reflected. The energy of the wave would be gradually dissipated by the resistance of the wire of this back-and-forth motion (oscillation); however, each time it reaches the starting point, the wave is reinforced by an amount sufficient to replace the energy lost. This results in continuous oscillations of energy along the wire and a high voltage at the A end of the wire. These oscillations are applied to the antenna at a rate equal to the frequency of the rf voltage. These impulses must be properly timed to sustain oscillations in the antenna. The rate at which the waves travel along the wire is constant at approximately 300,000,000 meters per second. The length of the antenna must be such that a wave will travel from one end to the other and back again during the period of 1 cycle of the rf voltage. 16

17 Remember, the distance a wave travels during the period of 1 cycle is known as the wavelength and is found by dividing the rate of travel by the frequency. Look at the current and voltage (charge) distribution on the antenna in figure 4-6.Amaximum movement of electrons is in the centre of the antenna at all times; therefore, the centre of the antenna is at a low impedance. This condition is called a STANDING WAVE of current. The points of high current and high voltage are known as current and voltage LOOPS. The points of minimum current and minimum voltage are known as current and voltage Noise shows a current loop and current nodes. View B shows voltage loops and a voltage node. View C shows the resultant voltage and current loops and nodes. The presence of standing waves describes the condition of resonance in an antenna. At resonance the waves travel back and for thin the antenna reinforcing each other and the electromagnetic waves are transmitted into space at maximum radiation. When the antenna is not at resonance, the waves tend to cancel each other and lose energy. 17

18 The wave bounces back (reflects) from this point of high impedance and travels toward the starting point, where it is again reflected. The energy of the wave would be gradually dissipated by the resistance of the wire of this back-and-forth motion (oscillation); however, each time it reaches the starting point, the wave is reinforced by an amount sufficient to replace the energy lost. This results in continuous oscillations of energy along the wire and a high voltage at the A end of the wire. These oscillations are applied to the antenna at a rate equal to the frequency of the rf voltage. 18

19 CHAPTER 7 RADIO :- An audio signal (top) may be carried by an AM or FM radio wave Radiation Edwin Howard Armstrong (1890±1954) was an American electrical engineer who invented frequency modulation (FM) radio. He patented the regenerative circuit in 1914, the super heterodyne receiver in 1918 and the super-regenerative circuit in He presented his paper: "A Method 19

20 of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation", which first described FM radio, before the New York section of the Institute of Radio Engineers on November 6, The paper was published in As the name implies, wideband FM(W- FM) requires a wider signal band width than amplitude modulation by an equivalent modulating signal, but this also makes the signal more robust against noise and interference. Frequency modulation is also more robust against simple signal amplitude fading phenomena. As a result, FM was chosen as the modulation standard for high frequency, high fidelity radio transmission: hence the term "FM radio"(although for many years the BBC called it "VHF radio", because commercial FM broadcasting uses a well-known part of the VHF band -- the FM broadcast band. FM receivers employ a special detector for FM signals and exhibit a phenomenon called capture effect, where the tuner is able to clearly receive the stronger of two stations being broadcast on the same frequency. Problematically however, frequency drift or lack of selectivity may cause one station or signal to be suddenly overtaken by another on an adjacent channel. Frequency drift typically constituted a problem on very old or inexpensive receivers, while inadequate selectivity may plague any tuner. An FM signal can also be used to carry a stereo signal: see FM stereo. However, this is done by using multiplexing and demultiplexing before and after the FM process. The rest of this article ignores the stereo multiplexing and demultiplexing process used in "stereo FM", and concentrates on the FM modulation and demodulation process, which is identical in stereo and mono processes. A highefficiency radio-frequency switching amplifier can be used to transmit FM signals CHAPTER 8 DESCRIPTION OF COMPONENTS USED 8.1 Transistor 20

21 Introduction: The transistor is a semiconductor device than can function as a signal amplifier or as a solid-states witch.a typical switching circuit using a PNP transistor is shown at the left. In a transistor a very small current input signal flowing emitter-to-base is able to control a much larger current which flows from the system power supply, through the transistor emitter-tocollector, through the load, and back to the power supply. In this example the input control signal loop is shown in red and the larger output current loop is shown in blue. With no input the transistor will be turned OFF (cutoff) and the relay will be dropped out. When the low-level input from the PLC microprocessor turns the transistor ON (saturates) current flows from the power supply, through the transistor, and picks the relay. Transistor Packages There are many transistor case designs. Some conform to JEDEC Standards and are defined by Transistor Outline (TO) designations. Several case designs are illustrated below. Solid -state devices other than transistors are also housed in these same packages. In general, the larger the unit, the greater the current or power rating of the device There are three main classifications of transistors each with its own symbols,characteristics, design parameters, and applications. See below and the following pages for additional details and applications on each of these transistor types. Several special-function transistor types also exist which do not fall into the categories below such as the uni junction (UJT) transistor that is used for SCR firing and time delay applications. These special function devices are described separately. 21

22 Bipolar transistors are considered current driven devices and have a relatively low input impedance. They are available as NPN or PNP types. The designation describes the polarity of the semiconductor material used to fabricate the transistor..field Effect Transistors, FET s, are referred to as voltage driven devices which have a high input impedance. Field Effect Transistors are further subdivided into two classifications: 1) Junction Field Effect Transistors, or JFET Transistors or MOSFET used in it. s, and 2) Metal Oxide Semiconductor Field Effect Insulated Gate Bipolar Transistors, known as IGBT s, are the most recent transistor development. This hybrid device combines characteristics of both the Bipolar Transistor with the capacitive coupled, high impedance input, of the MOS device. 22

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24 Transistor testing 8.2 PNP Test Procedure Connect the meter leads with the polarity as shown and verify that the base-to-emitter and base-to collector junctions read as a forward biased diode: 0.5 to 0.8 VDC. 24

25 Reverse the meter connections to the transistor and verify that both PN junctions do not conduct. Meter should indicate an open circuit. (Display = OUCH or OL.) Finally read the resistance from emitter to collector and verify an open circuit reading in both directions. (Note: A short can exist from emitter to collector even if the individual PN junctions test properly. 25

26 8.3 NPN Test Procedure Connect the meter leads with the polarity as shown and verify that the base-to-emitter and base-to collector junctions read as a forward biased diode: 0.5 to 0.8 VDC. Reverse the meter connections to the transistor and verify that both PN junctions do not conduct. Meter should indicate an open circuit.(display = OUCH or OL.) Finally read the resistance from emitter to collector and verify an open circuit reading in both directions.(note: A short can exist from emitter to collector even if the individual PN junctions test properly.) 8.4 Transistor 2N2222: The 2N2222, often referred to as the 'quad two' transistor, is a small, common NPN BJT transistor used for general purpose low-power amplifying or switching applications. It is designed for low to medium current, low power, medium voltage, and can operate at moderately high speeds.it was originally made in the TO-18 metal can as shown in the picture, but is more commonly available now in the cheaper TO-92 packaging, where it is known as the PN2222 or P2N

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28 CHAPTER 9 WHAT HAVE WE DONE? We have :i.e made our own inductor for the project. This inductor has a value falling in micro henry range. For this, we took 16 AWG enamelled copper wire and wound it on a 9 mm former, giving it 6 turns in total. Then we removed the former and obtained an inductor of desired value.ii.implemented the circuit on multi sim. We designed the circuit on Multi sim software, gave the components the required values and tested it for proper functioning. Next, we observed the output waveforms being transmitted from the inductor. The circuit designed and the output waveform produced are shown below: 28

29 designed the circuit on a PCB.Then, we released the whole circuit physically to see its practical working. For this, we used a Printed Circuit Board and joined the various components on the PCB with a connecting wire using soldering it. Points to be kept in mind: *For L1 make 6 turns of 16AWG enamelled copper wire on a 9mm plastic former. *The circuit can be powered using a 9V PP3 battery. *For extended range, use an antenna. *A 30cm long wire connected anywhere on the coil will do for the antenna. *For better performance, assemble the circuit on a good PCB. Modus Operandi: *This circuit simply generates VHF (Very High Frequency) waves. *These waves interfere with the FM waves being transmitted. *This interference is destructive in nature and thus the FM waves are blocked. 29

30 CHAPTER:-10 RESULT Our intention is to block MHz signal which is AIR Hamirpur in vicinity. From circuit diagram we have C9 =33 pf and L=112 uh C= 2.22 uf. Therefore, the value at which Varicap is to be tuned is equal to pf which is approximately equal to 33 pf. The circuit maker simulation of the FM transmitter as jammer is shown in the subsequent plot. 30

31 CHAPTER:-11 APPLICATIONS: During a hostage situation, police can control when and where a captor can make a phone call. Police can block phone calls during a drug raid so suspects can't communicate outside the area. Cell-phone jammers can be used in areas where radio transmissions are dangerous, (areas with a potentially explosive atmosphere), such as chemical storage facilities or grain elevators. It can be used in places like Hospitals, restaurants, movie theatres, concerts, shopping malls and churches where silence is required. Examination Halls, where there are chances of high some fraud, can install this system to block this radio signal so that no communication can take place from outside. (To stop Munna Bhai Effect... don t be serious) 31

32 CHAPTER 12 APPENDICES:- (A) TRAI: 32

33 (B) Data Sheet of LM 358 Internal Block Diagram 33

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36 CHAPTER 13 Bibliography Annual Report 2008, Telecom Regulatory Authority of India (TRAI). Electronic Communication Systems by Kennedy and Davis. Linear Integrated Circuit by Ramakant A. Gayakward. Signals and systems By B.P. Lathi FM Transmitter (Google Search) Electromagnetic Field Theory by KD Prasad. Circuit Maker Manual. 36

37 CONCLUSION FM Jammer is used for the cell phones and radio receivers are used everywhere these days. It s great to be able to call anyone anytime. But unfortunately, restaurants, movie theatres, concerts, shopping malls and churches all suffer from the spread of cell phones because not all cell phone users know when to stop talking. While most of us just grumble an move on some people are actually going to extremes to retaliate. 37