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. Frequency modulation definition of frequency modulation. Frequency modulation fm, as well as phase modulation pm, are types of angle exponential modulation. Vary the modulating frequency and amplitude and observe the effects on the modulated waveform. In this experiment, the properties and characteristics of amplitude modulated amsignals and their frequency spectra are examined. Instantaneous frequency the instantaneousfrequencyof cos. 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. The percentage modulation can be calculated using the formula.
The radio wave was called a carrier, since it was seen to carry the speech information with it. Frequencymodulation article about frequencymodulation by. To perform the frequency modulation and demodulation using fm kit. Frequency modulation software free download frequency.
A circuit was then implemented to demodulate the signals via phase. It is often called as am and is commonly used in transmitting a piece of information through a radio carrier wave. Build simple fm demodulator by using frequency discriminator 2. Frequency modulation definition and meaning collins. Discover the best frequency modulation books and audiobooks. Vary the modulating frequency and amplitude and observe the effects on the modulated. In the context of radio communication, near the end of the 2oth century, few modulated signals contain a significant component at carrier frequency. Pdf analog communication system pdf notes ac notes sw.
Feel free to use the lab to practice your skills before the experiment. Powered by amrita virtual lab collaborative platform ver 00. The process and the signal were called amplitude modulation, or am for short. The heterodyne principle is the basic idea governing several different modulation schemes. Jan 21, 2018 in this physics video lecture in hindi for class 12 we explained modulation and demodulation in communication system. There are many di erent ways one can put information in it. Frequency modulation article about frequency modulation by. To understand the theoretical foundations for angle modulation as well as frequency modulation fm and demodulation. Analog communications lab manual pdf ac lab manual pdf. 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. Weexpresstheresultinganglewe express the resulting anglemodulatedwaveasmodulated wave as 4. 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 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. 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. From 2, the instantaneous frequency is obtained as f it f c. 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. Since the amplitude is kept constant, fm modulation is a. Frequencymodulation article about frequencymodulation. While amplitude modulation is achieved by varying e p, frequency modulation is realized by varying.
Lab 6frequency modulation formal report required groups of two this lab will have you create and analyze some simple frequency modulated fm waveforms. Build simple envelope detector for fm demodulation. 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. Recall that we can write an equation for a sine wave as follows. 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. This is a laboratory manual for analog communication experiments. Frequency modulation fm tutorial in digital and analog modulation tutorial basics duration. Here, we consider two representative schemes, namely, phase modulation and frequency modulation. Traditional broadcast radio modulation schemes like fm frequency modulation or am amplitude modulation are used because signals are picked up by many receivers. Using matlab mfile and simulink to implement fm modulation and demodulation. These are covered in chapter 5 of 2, or chapter 3 of 1. Build simple fm demodulator by using frequency discriminator.
Frequency modulation fm is a type of modulation where the frequency of the carrier is varied in accordance with the modulating signal. Complete notes download link ac notes analog communication pdf free download unit i introduction. Frequency modulation fm is a process in which the carrier frequency is. This technique contrasts with frequency modulation, in which the frequency of the carrier signal is. It is this process that is called demodulation or detection. Frequency modulationsimulation experiment introduction.
Amplitude modulation and frequency modulation are two types of analog signal. Frequency modulation fm is a process in which the carrier frequency is varied by the amplitude of the modulating signal i. Designing and analyzing frequency modulator and demodulator objective. It is also possible to change the frequency of a signal to give frequency modulation or fm.
Introduction to communication system, need for modulation, frequency division multiplexing, amplitude modulation, definition, time domain and frequency domain description. Frequency modulation fm is widely used in audio transmission, not only for its namesake fm radio, but. 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. Amplitude modulation am is a modulation technique used in electronic communication, most. Each radio station is assigned 200 khz, to transmit a stereo audio. While changing the amplitude of a radio signal is the most obvious method to modulate it, it is by no means the only way. Hapter modulation and demodulation free online course.
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. Techniques in virtual instrumentation and remote lab. Also see modulation and frequency shift keying fsk. Amplitude modulation definition, types, solved examples. 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. Using amplitude modulation to shift the baseband signal fm radio 88mhz108 mhz. Also before coming to the lab, you should complete the lab preparation and hand it to the t. Fm modulation and demodulation electrical and computer. However if st is sinusoidal, then the instantaneous frequency deviation of the anglemodulated signal is. Frequency modulation fm tutorial in digital and analog modulation tutorial basics. Amplitude modulation is mostly used in the form of electronic communication. 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.
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. 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. To send these electromagnetic waves across long distances in free space, the frequency of the transmitted signal must be quite high compared. Prelab theory a frequency modulation fm waveform can be represented mathematically by. There are two common forms of angle modulation, namely, phase modulation and frequency modulation.
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. The depth of modulation can be varied using the variable knob provided at a. Frequency modulation is widely used on frequencies above 30 mhz, and it is particularly well known for its use for vhf fm broadcasting. And why would that still be called frequency modulation. The information bearing signal the modulating signal changes the instantaneous frequency of the carrier. Fm signals are used in technology such as radars, telemeters, eeg, radio broadcasting, satellite communication and magnetic tape recording systems. Frequency modulation fm is the standard technique for highfidelity communications as is evident in the received signals of the fm band 88108 mhz vs.
Frequency modulation software free download frequency modulation top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices. Frequency modulation article about frequency modulation. An important feature of angle modulation is that it can provide better. Set the sampling frequency to 1khz and carrier frequency to 200 hz. An am modulator is constructed usingthe analog devices ad534 four quadrant multiplier, and the properties of the resultingsignal are examined using labview. What is fm, frequency modulation electronics notes. Once the signal has been received, filtered and amplified, it is necessary to recover the original modulation from the carrier. Modulation for analog nyu tandon school of engineering. Read frequency modulation books like ford sync with myford touch handbook and frequency modulation theory for free with a free 30day trial. Frequency modulation is a process of changing the frequency of a carrier wave in accordance with the slowly varying base band signal. Unicamp university of campinas, state of sao paulo pdf. The goal of this experiment is to become familiar with fm modulation and demodulation. 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. T he classic definition of fm is that the instantaneous output frequency of a transmitter is varied in accordance with the modulating signal.
Its main advantage is that it is more resistant to additive noise than am. Hapter modulation and demodulation free online course materials. Fm demodulation is a key process in the reception of a frequency modulated signal. Chapter 8 frequency modulationfm fm was invented and commercialized after am. Frequency modulation definition and meaning collins english. Learn from frequency modulation experts like ford motor company and jacques fagot. The modulation index can be used to make the frequency deviation more sensitive or less sensitive to variations in the baseband value. Discover frequency modulation books free 30day trial. A message signal was sent through a function generator, producing outputs at different rms values. Lab 5 amplitude modulation and demodulation pages 1 7. Amplitude modulation is a process by which the wave signal is transmitted by modulating the amplitude of the signal. In this physics video lecture in hindi for class 12 we explained modulation and demodulation in communication system. In words, the angle is used to carry information in a. Pdf simulation of analog modulation and demodulation.
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