Frequency modulation is widely used for radio transmission due to the fact that the signaltonoise ratio snr is large in this method of modulation and hence radio frequency interference is minimized. Analog communications lab manual pdf ac lab manual pdf. Prelab theory a frequency modulation fm waveform can be represented mathematically by. Build simple fm demodulator by using frequency discriminator. Frequency modulation fm is the standard technique for highfidelity communications as is evident in the received signals of the fm band 88108 mhz vs. Discover frequency modulation books free 30day trial. Hapter modulation and demodulation free online course. It is this process that is called demodulation or detection. Frequency modulation fm is a type of modulation where the frequency of the carrier is varied in accordance with the modulating signal. The process and the signal were called amplitude modulation, or am for short. Build simple envelope detector for fm demodulation. Fm modulation and demodulation electrical and computer. Frequency modulation article about frequency modulation. Frequency modulation fm the process of combining the message signal with the carrier signal that causes the message signal to vary the frequency of the carrier signal.
To implement the simulink models for fm including a basic sinusoid and a multimedia file music to analyze each signal in time and frequency domains. Since the amplitude is kept constant, fm modulation is a low noise process and provides a high quality modulation technique which is used for music and speech in hifidelity broadcasts. To send these electromagnetic waves across long distances in free space, the frequency of the transmitted signal must be quite high compared. There are many di erent ways one can put information in it. This technique contrasts with frequency modulation, in which the frequency of the carrier signal is. In words, the angle is used to carry information in a. To perform the frequency modulation and demodulation using fm kit. In this experiment, the properties and characteristics of amplitude modulated amsignals and their frequency spectra are examined. Lab 6frequency modulation formal report required groups of two this lab will have you create and analyze some simple frequency modulated fm waveforms. Recall that we can write an equation for a sine wave as follows. In telecommunications and signal processing, frequency modulation fm is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave in analog frequency modulation, such as fm radio broadcasting of an audio signal representing voice or music, the instantaneous frequency deviation, the difference between the frequency of the carrier and its center. Frequency modulation definition and meaning collins. The left and right channels each limited to 15khz are multiplexed into a single baseband signal using amplitude modulation using frequency modulation to shift the baseband.
Frequency modulation fm, as well as phase modulation pm, are types of angle exponential modulation. An am modulator is constructed usingthe analog devices ad534 four quadrant multiplier, and the properties of the resultingsignal are examined using labview. This is a laboratory manual for analog communication experiments. Frequency modulation fm is widely used in audio transmission, not only for its namesake fm radio, but. Frequency modulation definition and meaning collins english. T he classic definition of fm is that the instantaneous output frequency of a transmitter is varied in accordance with the modulating signal. Also see modulation and frequency shift keying fsk. Jan 21, 2018 in this physics video lecture in hindi for class 12 we explained modulation and demodulation in communication system. Frequency modulation software free download frequency modulation top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices. Pdf analog communication system pdf notes ac notes sw. Unicamp university of campinas, state of sao paulo pdf. There are two common forms of angle modulation, namely, phase modulation and frequency modulation. The modulation index can be used to make the frequency deviation more sensitive or less sensitive to variations in the baseband value. While amplitude modulation is achieved by varying e p, frequency modulation is realized by varying.
The heterodyne principle is the basic idea governing several different modulation schemes. The vco has an input voltage of 2v and is running at its free running. The factor 2 in the equation is to account for both the upper and lower sidebands left and. It is often called as am and is commonly used in transmitting a piece of information through a radio carrier wave. In this physics video lecture in hindi for class 12 we explained modulation and demodulation in communication system. An important feature of angle modulation is that it can provide better.
Frequency modulation software free download frequency. Frequency modulation fm tutorial in digital and analog modulation tutorial basics. Frequency modulationsimulation experiment introduction. Frequency modulation definition of frequency modulation. Lab 5 amplitude modulation and demodulation pages 1 7. Set the sampling frequency to 1khz and carrier frequency to 200 hz. Amplitude modulation definition, types, solved examples. Since the amplitude is kept constant, fm modulation is a. Its main advantage is that it is more resistant to additive noise than am. The percentage modulation can be calculated using the formula. Each radio station is assigned 200 khz, to transmit a stereo audio. Fm is a so called angle modulation scheme, it was inspired by phase modulation but has proved to be more useful partly for its ease of generation and decoding. A message signal was sent through a function generator, producing outputs at different rms values.
Vary the modulating frequency and amplitude and observe the effects on the modulated waveform. These are covered in chapter 5 of 2, or chapter 3 of 1. What is fm, frequency modulation electronics notes. Powered by amrita virtual lab collaborative platform ver 00. Frequency modulation is a process of changing the frequency of a carrier wave in accordance with the slowly varying base band signal. Modulation for analog nyu tandon school of engineering. Frequency modulation fm is a process in which the carrier frequency is. Amplitude modulation is a process by which the wave signal is transmitted by modulating the amplitude of the signal. Introduction to communication system, need for modulation, frequency division multiplexing, amplitude modulation, definition, time domain and frequency domain description. Frequency modulation fm tutorial in digital and analog modulation tutorial basics duration. Sysc 3501 lab 3 report rashad alsaffar 101006781 mohammad danyal 101003904 1 introduction the purpose of this lab was to understand the concepts of frequency modulation and phase modulation.
Using matlab mfile and simulink to implement fm modulation and demodulation. The mathematical representation of frequency modulation consists of a sinusoidal expression with the integral of the baseband signal added to the argument of the sine or cosine function. Learn from frequency modulation experts like ford motor company and jacques fagot. Frequency modulation fm is a process in which the carrier frequency is varied by the amplitude of the modulating signal i. And why would that still be called frequency modulation. Phase and frequency modulations are techniques that modify the instantaneous phase and frequency, respectively, of a sinusoid in a way dictated by an information signal f. Nov 11, 2016 frequency modulation is widely used for radio transmission due to the fact that the signaltonoise ratio snr is large in this method of modulation and hence radio frequency interference is minimized.
In the context of radio communication, near the end of the 2oth century, few modulated signals contain a significant component at carrier frequency. Discover the best frequency modulation books and audiobooks. Fm demodulation is a key process in the reception of a frequency modulated signal. The depth of modulation can be varied using the variable knob provided at a. Once the signal has been received, filtered and amplified, it is necessary to recover the original modulation from the carrier. Also before coming to the lab, you should complete the lab preparation and hand it to the t. However if st is sinusoidal, then the instantaneous frequency deviation of the anglemodulated signal is. Vary the modulating frequency and amplitude and observe the effects on the modulated. Pdf simulation of analog modulation and demodulation. Traditional broadcast radio modulation schemes like fm frequency modulation or am amplitude modulation are used because signals are picked up by many receivers. Weexpresstheresultinganglewe express the resulting anglemodulatedwaveasmodulated wave as 4. Frequencymodulation article about frequencymodulation. A circuit was then implemented to demodulate the signals via phase. Techniques in virtual instrumentation and remote lab.
Frequency modulation article about frequency modulation by. The information bearing signal the modulating signal changes the instantaneous frequency of the carrier. Chapter 8 frequency modulationfm fm was invented and commercialized after am. Hapter modulation and demodulation free online course materials. Amplitude modulation am is a modulation technique used in electronic communication, most. It is also possible to change the frequency of a signal to give frequency modulation or fm. Frequency modulation please go to experiment 11 in the emona datex lab manual volume1 and follow all the steps and necessary connections from page 114 till page 1115 to answer the following questions. While changing the amplitude of a radio signal is the most obvious method to modulate it, it is by no means the only way. A disadvantage of the am, dsbsc and other form of amplitudemodulation communication systems is that they are susceptible to picking up electrical noise in the transmission medium the channel. Read frequency modulation books like ford sync with myford touch handbook and frequency modulation theory for free with a free 30day trial. Amplitude modulation is mostly used in the form of electronic communication. Fm signals are used in technology such as radars, telemeters, eeg, radio broadcasting, satellite communication and magnetic tape recording systems. Modulation is the process in which some property of the high frequency wave, also called as carrier wave c, is altered in such way by low frequency information signal, called as.
In telecommunications and signal processing, frequency modulation fm is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave in analog frequency modulation, such as fm radio broadcasting of an audio signal representing voice or music, the instantaneous frequency deviation, the difference between the frequency of the. Instantaneous frequency the instantaneousfrequencyof cos. From 2, the instantaneous frequency is obtained as f it f c. Cannel capacity and ideal communication systems, intersymbol interference, bandpass signaling, am, fm, pm modulated sysetms, phase modulation and frequency modulation, output signalto noise ratios for analog systems, binary modulated bandpass signaling, 8psk modulation, multilevel modulated bandpass signaling. Using amplitude modulation to shift the baseband signal fm radio 88mhz108 mhz. Build simple fm demodulator by using frequency discriminator 2. To understand the theoretical foundations for angle modulation as well as frequency modulation fm and demodulation. The goal of this experiment is to become familiar with fm modulation and demodulation. Feel free to use the lab to practice your skills before the experiment. Complete notes download link ac notes analog communication pdf free download unit i introduction.
Frequencymodulation article about frequencymodulation by. Frequency modulation is widely used on frequencies above 30 mhz, and it is particularly well known for its use for vhf fm broadcasting. Designing and analyzing frequency modulator and demodulator objective. The radio wave was called a carrier, since it was seen to carry the speech information with it. Here, we consider two representative schemes, namely, phase modulation and frequency modulation.
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