Analog modulation uses mainly am amplitude and fm frequency modulations. This is further developed as delta modulation dm, which will be discussed in subsequent chapters. Classification and types of analog modulation double sideband suppressed carrierdsb sc introduction. Nov 26, 2014 phase modulation is a subcategory of frequency modulation, whereby the phase angle of the carrier envelope is modified in response to changes in the signal. This page compares analog modulation vs digital modulation and describes difference between analog modulation and digital modulation. Also, output level is not dependent on optical level, and there is no degradation of signals through the system to the point that they go away, of course. Amplitude modulated signal and frequency modulated signals are the examples of analog communication. Although there are many types of modulation, there are two basic types. Coding is not applied to the signal as in case of digital data. Principles of communication modulation tutorialspoint. The digital modulation or dm is one kind of modulation, which utilizes discrete signals to change a carrier wave. Sep 28, 2015 analog and digital modulation refers to how a carrier signal is modified in order to transmit information.
The two common forms of analog modulation are amplitude modulation. Digital modulation in communications systems an introduction. Digital to analog conversion techniques myreadingroom. Digital modulation an overview sciencedirect topics. This kind of modulation eliminates the noise of communication and provides superior power for the signal interruption. In general when we talk about a digital system, we are usually talking about digital information over an analog medium.
In pulse width modulation, there are different types of modulation for analog and digital as shown below. For a better quality and efficient communication, digital modulation technique is employed. The general function sinusoidal waves is shown in the figure below, in which, three parameters can be altered to get modulation they are amplitude, frequency and phase. Display of dialed telephone numbers on seven segment displays.
Different types of modulation techniques in communication systems. As the resultant is a coded pulse train, this is called as pcm. We can see 3 parameters that can be changed in this sine wave to send information. The main advantage of the digital modulation over analog modulation include high noise immunity, available bandwidth, and permissible power.
Digital modulation types and relative efficiencies. Modulation of analog data 2 why analogtoanalog modulation. Before jumping to difference between analog and digital modulation types let us understand about modulation basics. The digital modulation technique is employed for efficient communication. The two binary states, logic 0 low and 1 high, are each represented by an analog waveform. Pulse coded modulation pcm is a form of modulation where there is no carrier, so. Modern mobile communication systems use digital modulation techniques. In digital modulation, the modulation technique used is pulse code modulation pcm where the analog signal is converted into digital form of 1s and 0s. Cell phone based dtmf controlled garage door opening system. The main advantages of the digital modulation over analog modulation include available bandwidth, high noise immunity and permissible power.
The radios are examples of analog data over analog medium. In digital modulation, an analog carrier signal is modulated by a discrete signal. The only difference between both categories is type of information modulating signal. Fsk frequency shift keying oqpsk offsetquaternary phase shift keying ofdm orthogonal frequency division multiplexing dsss. The am and fm radios are examples of analog data over analog medium. Modulation techniques pwm and pulse code modulation. This set of data communication and networking multiple choice questions and answers mcqs focuses on digital to analog to encoding modulation techniques amplitudeshift keying ask frequencyshift keying fsk phaseshift keying psk quadrature amplitude modulationqam. Or the process of modulation can be defined as varying the rf carrier wave in accordance with the intelligence or information in a low frequency signal. Signal is defined as the useful information which is sanded by the transmitter and received by the receiver.
Frequency modulation the frequency of the carrier signal is proportional to the modulating. Modulation, analog modulation, digital modulation, am,fm,pm, ask. Analog and digital pulse modulation techniques need. In digital wireless communication systems, the modulating. Analog communications 26 other modulation methods amplitude modulation the amplitude of the carrier signal is controlled by the modulating signal pitfall of am. Communication systemsanalog modulation introduction. In pulse width modulation or pulse duration modulation, the width of the pulse carrier is varied in accordance with the sample values of message signal or modulating signal or modulating voltage. Analog modulation delas with the voice, video and regular waves of base band signals. In cw modulation schemes some parameter of modulated wave varies.
Where as digital modulations are with bit streams or symbols from computing vevices as base band signals. Pdf analog and digital modulation techniques assignment 1. Analog to analog conversion analogtoanalog conversion, or modulation, is the representation of analog information by an analog signal. Carrier modulation and demodulation types of analog modulation technique i. In digital modulation, the modulating signal or message signal is converted from analog to digital. Pdf analog and digital modulation techniques assignment. Pdf on jul 1, 2017, vidyarani k r and others published. This article discusses an overview of what is modulation and what are the different types of modulation techniques involved in it. Easier multiplexing of various forms of information like voice. Analog and digital modulation techniques assignment 1. Pulse modulation timedivision multiplex tdm continued time multiplexing of two pam signals continued method 2. Modulation, analog modulation, digital modulation, am,fm. Pdf implementation of analog modulation techniques using.
Ee4512 analog and digital communications chapter 6 the dsbsc am coherent receiver has a bandpass filter centered at f c and with a bandwidth of twice the bandwidth of st because of the lsb and usb. Modulation makes it possible to transmit analog or digital signal over the air or through the. Modulation is the process of superimposing a low frequency signal on a high frequency carrier signal. Ask amplitude shift keying a digital modulation method that sends transmission data by varying the presenceabsence of analog signals. There are two types of modulation analog and digital. Frequencyshift keying fsk is a method of transmitting digital signals. Digital modulation schemes have greater capacity to convey large amounts of information than analog modulation schemes. Chapter 6modulation techniques shandong university. Therefore, dm techniques have a huge demand due to their capacity for communicating superior amounts of information than am analog modulation techniques.
Advantages of digital modulation allows information to be packetized can compress information in time and efficiently send as packets through network in contrast, analog modulation requires circuitswitched connections that are continuously available. Pulse duration modulation pdm or pulse width modulation pwm. Phase modulation is used in many transmission applications, notably wifi and satellite tv. Demodulation channel decoding is the corresponding process at the receiver of converting the received waveform into a. Many signals in modern communication systems are digital also, analog signals are transmitted digitally. Ee4512 analog and digital communications chapter 6 the analytical signal for double sideband, large carrier amplitude modulation dsblc am is. The design of a communication system is application modulation oriented and is dependent on the type of the signal. Reduced distortion and improvement in signal to noise ratios. In analog modulation, analog signal sinusoidal signal is used as a carrier signal that modulates the message signal or data signal. These digital modulation techniques are discussed in our digital. Automatic dialing to any telephone using i2c protocol on detecting burglary. An analog signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity i. Modulation definition need for modulation types of. Pulse digital modulation is also used in both analog and digital communications.
Aug 28, 2015 when we take the pulse digital modulation, we use a periodic sequence of rectangular pulses as the carrier signal. The process of varying any of the three characteristics as the amplitude, frequency or the phase of a carrier signal is called as modulation we know that the information signal to be transmitted can be of any form such as data, music, video etc. In both the techniques, the baseband information is converted to radio frequency signals, but in analog modulation these rf communication signals are continuous range of values, whereas in digital modulation these are prearranged discrete states. Because there are two possible wave phases, bpsk is sometimes called biphase modulation. Frequency modulation fm is the most popular analog modulation. Digital modulation dm gives more capacity of data, high information security, and accessibility of a faster system by enormous quality communication. An advantage of digital modulation is that it can operate with much lower signal to noise ratio than can analog modulation, as shown in figure 4. Analog digital modulation lanalog modulation l the input is continues signal l used in first generation mobile radio systems such as amps in usa. Analog to analog conversion modulation geeksforgeeks. Digital modulation aims at transferring a digital bit stream over an analog. This term is called the amplitude, and changing it is called amplitude modulation am. Demodulation is the opposite process of modulation.