Difference between pam, pwm, and ppm comparison of pwm and pam. By varying the amplitude of the pulses the carrier signal in proportion to the instantaneous values of the analog signal the message. This page on modulator vs demodulator covers basics of modulator and demodulator and also mention difference between modulator and demodulator. Another way of expressing the modulation index is in terms of the maximum and minimum values of the amplitude of the modulated carrier wave. A demodulator is an electronic circuit that is mainly used to recover the information content from the modulated carrier wave. Ee4512 analog and digital communications chapter 6 the analytical signal for double sideband, large carrier amplitude modulation dsblc am is. Frequency modulation consists of encoding information onto a carrier signal by varying the frequency of the carrier. Difference between modulation and demodulation compare the. Both modulation and demodulation are reverse processes of each other. Both transmit the information in the form of electromagnetic waves.
The continuous wave modulation techniques are further divided into amplitude modulation and angle modulation. In general, radio carrier generates at the transmission side of a telecommunication link. Radio waves can carry audio, video, and digital information over great distances by using changes in a carrier waves amplitude, frequency, or phase to represent the information being transmitted. Hapter modulation and demodulation mit opencourseware. We shall focus more on frequency modulation in this course and less on phase modulation. Modulator vs demodulatordifference between modulator. The receivers used to listen to amdsbc are perhaps the simplest receivers of any radio modulation technique. Communication systemsamplitude modulation wikibooks, open. This page on modulator vs demodulator covers basics of modulator and demodulator and also mention difference between modulator and demodulator as we know in telecommunication, in order to send information to longer distance and to take care of high bit rate requirement of the system different modulation techniques are employed. Amplitude modulation am is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. There are different types of modulation and so are demodulators.
Difference between modulation and demodulation with. Am or amplitude modulation and fm or frequency modulation are ways of broadcasting radio signals. Modulation and demodulation based interview questions. The output signal via demodulator may describe the sound, images or binary data. Use dcs600007 module xr 2206 modulator to modulate data signal 200 hz ttl, let j2 and j5. Quadrature frequency and phase demodulation radio frequency. Pass through reference and signal fibers twice, phase shift per unit length doubled. Difference between amplitude modulation and frequency modulation. Demodulation is the opposite process of modulation.
Modulation, analog modulation, digital modulation, am,fm,pm. Some phase modulation and quadrature amplitude modulation formats have a higher spectral efficiency for data transmission than frequency shift keying, a form of frequency modulation. This article provides a general tutorial on fsk in its many forms. Spectra have a typical trapezoidal shape in linear frequency and amplitude in decibels. Both modulation and demodulation schemes will be discussed binary fsk. Difference between modulation and demodulation compare. In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.
Once a signal has been modulated, information is retrieved through a demodulation process. For a perfect modulation, the value of modulation index should be 1, which means the modulation depth should be 100%. Encoding and modulation are two techniques used to provide the means of mapping information or data into different waveforms such that the receiver with the help of an appropriate demodulator and decoder can recover the information in a reliable manner. Modulation is the process of influencing data information on the carrier, while demodulation. A brief discussion about pulse code modulation and demodulation. Understanding iq signals and quadrature modulation radio. The modulating intelligence is contained in the difference between these frequencies. Quadrature demodulation can extract angle information that is relevant to both frequency modulation and phase modulation. The main difference between amplitude modulation and frequency modulation is that, in amplitude modulation, the amplitude of the carrier wave is modified according to the data whereas, in frequency modulation, the frequency of. Difference between am and fm amplitude modulation and frequency modulation are used to transmit data using the method of modifying a carrier signal. The term quadrature modulation refers to modulation that is based on the summation of two signals that are in quadrature. Modulationtypesamplitude,frequency,phase modulation. Analog modulation is cheaper to implement than digital modulation. Each channel sharing scheme a set of basis vectors.
Analog modulation delas with the voice, video and regular waves of base band signals. In transmission, it is necessary to send a signal a long. The vector addition of these frequencies provides the modulation envelope. There are two types of modulation analog and digital. Introduction in chapters 1 and 2 you studied how to apply intelligence modulation to an rfcarrier wave. In singlechannel efield sensing, the carrier we transmit is m, the sensed value is a, and the noise is n vectors. Pulse code modulation is a method that is used to convert an analog signal into a digital signal, so that modified analog signal can be transmitted through the digital communication network.
Describe phase demodulation circuit operation for the peak, lowpass filter, and conversion detectors. Here fc climbs slowly and will attain value equal to fd. Modulator vs demodulatordifference between modulator,demodulator. Pdf a moems accelerometer with high precision based on grating. Pcm is in binary form,so there will be only two possible states high and low 0 and 1. Difference between encoding and modulation compare the. Jul 19, 2011 the key difference between modulation and demodulation is that modulation is to transfer the message signal by adding it with the carrier signal while demodulation is the process of filtering out the actual message signal from the carrier signal.
Nov, 2006 hey guys, just wanted to know if any1 could please shred sum light on wat would the differnce in demodulation schemes of double side band suppressed carrier and single side band suppressed carrier. Dec 21, 2017 amplitude modulation is one of the earliest radio modulation techniques. Jun 09, 2017 demodulation is also very useful for diagnosing problems in rolling element bearings of very low speed machines. We can also get back our analog signal by demodulation. Classification and types of analog modulation double sideband suppressed carrierdsb sc introduction. Modulation is the process of altering the characteristics of the amplitude, frequency, or phase angle of the highfrequency signal in accordance with the instantaneous value of the modulating wave. Digital modulation produces more accurate output than analog modulation. It is a type of pulse time modulation ptm technique where the timing of the carrier pulse is varied according to the modulating signal in pulse duration modulation pdm, the amplitude of the pulse is kept constant and only the variation in width is noticed.
Among the types of modulation techniques, the main classification is continuouswave modulation and pulse modulation. The first step in the receiver will be demodulation of the received signal. This is what i done with matlab coding for modulation and demodulation. Interrogated with only single fiber between sourcedetector and sensor.
The key difference between modulation and demodulation is that modulation is done at the transmitter side while demodulation is done at the receiver side of a. For example, the signal in a cell phone is a voice signal with a. Similarly, when an analog signal is received, the modem converts it back demodulates it to a digital signal. The main difference between analog and digital modulation is that an analog modulated signal can take up any value in a possible range whereas a digitally modulated signal can only take up one of a discrete set of values.
Where as digital modulations are with bit streams or symbols from computing vevices as base band signals. What is the difference between economic theory and behavioral theory of how information systems affects organizations. Am works by modulating varying the amplitude of the signal or carrier transmitted according to the information being sent, while the frequency remains constant. Sep 28, 2015 analog and digital modulation refers to how a carrier signal is modified in order to transmit information.
The major difference between modulation and demodulation is that modulation is the act of altering the parameters of the carrier signal according to message. A continuouswave goes on continuously without any intervals and it is the baseband message signal, which contains the information. Pdf the modulation and demodulation module of a high. Carrier modulation allows the transmission of modulating frequencies without the use of transmission wire as a medium. Most radio systems in the 20th century used frequency modulation fm or. The key difference between modulation and demodulation is that modulation is to transfer the message signal by adding it with the carrier signal while demodulation is the process of filtering out the actual message signal from the carrier signal in general, radio carrier generates at the transmission side of a telecommunication link. Modulation and demodulation hold dominant positions in communication. In the circuit design, the modulated light intensity signal is converted to a voltage. When sending a signal, the device converts modulates digital data to an analog audio signal, and transmits it over a telephone line.
Modulation is the process of influencing data information on the carrier, while demodulation is the recovery of original information at the distant end from the carrier. The major difference between modulation and demodulation is that modulation is the act of altering the parameters of the carrier signal according to message signal for convenient data transmission. It is the extent of modulation denoted in percentage, and is denoted by m. If you have a machine that turns at 60 rpm 1 hz and you want to find bearing frequencies in a range between 3xrpm and 10xrpm, the frequency of those harmonics will be lower than 10 hz. The main difference between both modulations is that in frequency modulation, the frequency of the carrier wave is modified as per the transmit data, while in amplitude modulation, the carrier.
Signals and demodulation frequency shift keying fsk is the most common form of digital modulation in the highfrequency radio spectrum, and has important applications in telephone circuits. Gfsk vs fskdifference between gfsk and fsk modulation techniques. As we know in telecommunication, in order to send information to longer distance and to take care of high bit rate requirement of the system different modulation techniques are employed. Latest posts by ben joan see all difference between sony cybershot s series and w series december 22, 2012. Before going to discuss the difference between pam, pwm, and ppm, let us discuss individually each. Modulation and demodulation based interview questions and. On the contrary, demodulation is done in order to recover the original message signal from a modulated signal. A modem is an equipment that performs both modulation and demodulation. Radio systems can use a digital signal processor in conjunction with an analogtodigital converter to apply mathematical analysis to iq waveforms. Oct 05, 2015 amplitude modulation and frequency modulation are both methods of modifying a carrier signal in order to transmit data. Short for modulator demodulator, a modem is a hardware device that allows a computer to send and receive information over telephone lines. Analog modulation has a range of valid values while digital modulation only has two.
885 1229 1090 1238 778 20 14 323 1348 1260 1263 28 400 536 69 1490 920 1433 120 193 1435 815 261 606 217 1517 110 1204 1195 1299 180 1174 578 159 1462 437 589 1060 1192 1281 1437 1309 599