●
●
●
● Modulators for amplitude and phase modulations
□ Pulse Amplitude Modulation (M-PAM)
□
□
● Demodulators for amplitude and phase modulations
□ M-PAM detection
□ M-PSK detection
□ M-QAM detection
□ Optimum detector on IQ plane using minimum Euclidean distance
● M-ary FSK modulation and detection
□ Modulator for M orthogonal signals
□ M-FSK detection
Note: There is a rating embedded within this post, please visit this post to rate it. Added to cart | Note: There is a rating embedded within this post, please visit this post to rate it. Added to cart | Note: There is a rating embedded within this post, please visit this post to rate it. Added to cart |
|
hi sir, my project title is modelling and simulation of prime physical layer(ofdm) using matlab. so kindly pls give me the brief note of it and which modulation sheme and channels can be used when compared to existing? can you pls give me the coding for this too…….?
Privacy overview.
Cookie | Duration | Description |
---|---|---|
cookielawinfo-checbox-analytics | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics". |
cookielawinfo-checbox-analytics | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics". |
cookielawinfo-checbox-functional | 11 months | The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". |
cookielawinfo-checbox-functional | 11 months | The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". |
cookielawinfo-checbox-others | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other. |
cookielawinfo-checbox-others | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other. |
cookielawinfo-checkbox-necessary | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary". |
cookielawinfo-checkbox-performance | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance". |
viewed_cookie_policy | 11 months | The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data. |
Modulation is the Fundamental Process in Communication Systems, In Modulation Low-Frequency Message Signal Blends with High-Frequency Carrier Frequency to Enable Efficient Transfer of the Signal. In this article, we will be going through Digital Modulation Techniques, First we will start our Article by Defining Modulation, Then we will go through the Three types of Digital Modulation techniques with Their Wave, At Last we will conclude our Article With their Application, Advantages, Disadvantages and Some FAQs.
Table of Content
Frequency shift keying, phase shift keying, m-ary encoding.
Modulation is the process of superimposing high-frequency carrier signals with low-frequency message signals resulting in a modulated wave. In modulation, one of the three parameters of the carrier wave is changed i.e. amplitude, frequency or phase according to the amplitude of the message signal at a given time instant. It is an important technique used to increase the range of communication, increase the signal-to-noise ratio , and decrease the size of the antenna.
There are mainly two types of modulation techniques which are
Analog Modulation : In Analog Modulation, both carrier and message signals are analogue waves.
Digital Modulation : In Digital Modulation, only the carrier signal is analogue and the message signal is in digital form.
Analog waves : Analog waves are those signals which can take an infinite value between two points.
Digital signals : Digital signals are binary values that can take either logic 0 as in zero volts or logic 1 as in any other voltage. There are no in-between voltage levels in the digital signal.
Types of Signals
There are mainly three types in Analog Modulation which are Amplitude Modulation, Frequency Modulation and Phase Modulation. Here the amplitude, frequency and phase of carrier wave changes with respect to amplitude of message signal. Whereas in Digital Modulation a process called as Shift Keying is used.
Shift Keying means that the amplitude, frequency or phase of the carrier wave is shifted between two or more discrete values rather than varying continuously like Analog Modulation. Binary data requires two discrete levels of amplitude, frequency or phase for modulation called as Binary Shift Keying. A group of bits can be clubbed together to form M-ary Shift Keying.
There are mainly three types of Digital Modulation techniques. They are :
In Amplitude Shift Keying (ASK) , each symbol in the message signal gives a unique amplitude to the carrier wave. There are two types of ASK, Binary and M-ary. In Binary ASK, logic 1 is associated with certain amplitude of carrier wave e.g. 12V and logic 0 is associated with different amplitude other than 12V e.g. 0V. In M-ary ASK, a group of log 2 M bits are considered together rather than 1 bit at a time and the amplitude level is associated with this group of bits.
For example, in 16-ary ASK, a group of 4 bits are considered and are given a respective amplitude. Since there are 16 possible 4 bit binary numbers (2 4 ), 16 different amplitude levels are required for modulation. If all such amplitudes are created using a single carrier wave, then it is called as coherent ASK. If multiple carrier wave each with different amplitudes are used for modulation then it is called as non-coherent ASK.
Amplitude Shift Keying Waveform
Block Diagram of Amplitude Shift Keying
Given Below is the Block Diagram of Amplitude Shift Keying
The analog message signal is converted to digital signal using Analog to Digital Converter. This digital signal is then passed to a multiplier which takes two inputs. A sine wave with high frequency is considered as carrier signal and is multiplied with the digital signal. When symbol present in the digital signal m(t) gets multiplied with the carrier Asin(2πft+p) it results in m(t)Asin(2πft+p).
When m(t) is high, the carrier wave is passed as it is. But when m(t) is logic 0, then the result of multiplication is 0. Hence ASK wave is generated. However this ASK wave contains abrupt changes in amplitude which causes unnecessary high bandwidth usage. Hence this signal is passed through Band Pass Filter which limits the bandwidth usage.
For demodulating, the ASK wave is passed through a multiplier again where the carrier wave is multiplied again which results in m(t)Asin 2 (2πft+p). This signal is passed through Low Pass Filter where the original digital message is received. This digital signal is converted to analog wave using Digital to Analog Converter.
In Frequency Shift Keying (FSK), each symbol in the message signal gives a unique frequency to the carrier wave. There are two types of FSK, Binary and M-ary. In Binary FSK, logic 1 is associated with certain frequency of carrier wave e.g. 50MHz and logic 0 is associated with different frequency other than 50MHz e.g. 25MHz. In M-ary FSK, a group of log 2 M bits are considered together rather than 1 bit at a time and the frequency is associated with this group of bits.
For example, in 16-ary FSK, a group of 4 bits are considered and are given a respective frequency. Since there are 16 possible 4 bit binary numbers (2 4 ), 16 different frequencies are required for modulation . If all such frequencies are created using a single carrier wave, then it is called as coherent FSK. If multiple carrier wave each with different frequencies are used for modulation then it is called as non-coherent FSK.
Frequency Shift Keying Waveform
Block Diagram of Frequency Shift Keying
Given Below is the Block Diagram of Frequency Shift Keying
The analog message signal is converted to digital signal using Analog to Digital Converter . This digital signal is then passed to two multipliers which takes two inputs each. A sine wave with frequency f 1 is considered as carrier signal for logic 1 and a sine wave with frequency f 2 is considered as carrier signal for logic 0. These carrier waves are multiplied with the digital message signal. When logic 1 present in the digital signal gets multiplied with the carrier Asin(2πf 1 t+p) it results in Asin(2πf 1 t+p) only since the other multiplier gets logic 0 as input since it is passed through a NOT gate .
When logic 0 present in the digital signal gets multiplied with the carrier Asin(2πf 2 t+p) it results in Asin(2πf 2 t+p) only since the multiplier gets logic 1 as input since it is passed through a NOT gate. Both this signals are added to form FSK wave A[sin(2πf 1 t+p)+sin(2πf 2 t+p)]. However this FSK wave contains abrupt changes in frequency which causes unnecessary high bandwidth usage. Hence this signal is passed through Band Pass Filter which limits the bandwidth usage.
For demodulating, the FSK wave is passed through two multipliers again where their respective carrier waves are multiplied again. This signal is passed through two Band Pass Filters out of which the top BPF allows f 1 frequency to pass if logic is 1 and the bottom allows f 2 frequency to pass if logic is 0. The output of both BPF is compared with each other where the output of the comparator is high if output of BPF 1 is greater than output of BPF 2 and is low if output of BPF 2 is greater than output of BPF 1 . Hence a digital signal is received at the output of the comparator. This digital signal is converted to analog wave using Digital to Analog Converter .
In Phase Shift Keying (PSK), each symbol in the message signal gives a unique phase shift to the carrier wave. There are two types of PSK, Binary and M-ary. In Binary PSK, logic 1 is associated with certain phase shift of carrier wave e.g. 90 ° and logic 0 is associated with different phase shift other than 90 ° e.g. 0 ° . In M-ary PSK, a group of log 2 M bits are considered together rather than 1 bit at a time and the phase shift is associated with this group of bits.
For example, in 16-ary PSK, a group of 4 bits are considered and are given a respective phase shift. Since there are 16 possible 4 bit binary numbers (2 4 ), 16 different phase shifts are required for modulation. If all such phase shifts are created using a single carrier wave, then it is called as coherent PSK. If multiple carrier wave each with different phase shifts are used for modulation then it is called as non-coherent PSK.
Phase Shift Keying Waveform
Block Diagram of Phase Shift Keying
Given Below is the Block Diagram of Phase Shift Keying
The analog message signal is converted to digital signal using Analog to Digital Converter. This digital signal is then passed to two multipliers which takes two inputs each. A sine wave with phase shift p 1 is considered as carrier signal for logic 1 and a sine wave with phase shift p 2 is considered as carrier signal for logic 0. These carrier waves are multiplied with the digital message signal. When logic 1 present in the digital signal gets multiplied with the carrier Asin(2πft+p 1 ) it results in Asin(2πft+p 1 ) only since the other multiplier gets logic 0 as input since it is passed through a NOT gate.
When logic 0 present in the digital signal gets multiplied with the carrier Asin(2πft+p 2 ) it results in Asin(2πft+p 2 ) only since the multiplier gets logic 1 as input since it is passed through a NOT gate. Both this signals are added to form PSK wave A[sin(2πft+p 1 )+sin(2πft+p 2 )]. However this PSK wave contains abrupt changes in phases which causes unnecessary high bandwidth usage. Hence this signal is passed through Band Pass Filter which limits the bandwidth usage.
For demodulating, the PSK wave is passed through two multipliers again where their respective carrier waves are multiplied again. This signal is passed through two Band Pass Filters out of which the top BPF allows the signal with phase shift p 1 to pass if logic is 1 and the bottom allows the signal with phase shift p 2 to pass if logic is 0. The output of both BPF is compared with each other where the output of the comparator is high if output of BPF1 is greater than output of BPF2 and is low if output of BPF2 is greater than output of BPF1. Hence a digital signal is received at the output of the comparator. This digital signal is converted to analog wave using Digital to Analog Converter.
It Involves transmitting of more than two bits simultaneously on the same signal that can help to save bandwidth by efficiently utilizing the available frequency spectrum.
Digital Modulation techniques offer numerous advantages such as high immunity to noise, enhanced security through encryption, efficient bandwidth utilization, and high data accuracy. Despite requiring additional circuitry and power consumption, the benefits outweigh the drawbacks, making Digital Modulation important in modern communication systems. Its applications is used in military communication, mobile networks, broadcasting, radar systems, and more, contributing to the advancement and reliability of global communication networks.
Can we combine two or more modulation techniques.
It is possible to combine ASK, FSK and PSK. Combining different modulation techniques increases the number of symbols available which in turn increases the bit rate, because increasing the number of symbols increases the number of bits per symbol.
Yes, one type of Digital Modulation is Pulse Modulation where the message signal is analog and the carrier is digital whose amplitude, width and position is changed with respect to amplitude of message signal.
FDMA can be used with both Analog and Digital Modulation techniques. However FDMA is predominantly used with Analog Modulation since it can support TDMA and out of FDMA and TDMA, TDMA is commercially viable and has high spectral efficiency. Hence TDMA is used in Digital Modulation.
Similar reads.
IMAGES
VIDEO
COMMENTS
Modulation Catagories The modulated signal, x(t), is given by The modulation can be classified into two categories: Linear modulation: A modulation process is linear when both a(t)cos ζ(t) and a(t)sin ζ(t) terms are linearly related to the message information signal. Nonlinear modulation: when the modulating signal, ν(t),
e still used today with digital signals.1. Three basic digital modulation formats are still very popular with low data rate sho. t range wireless applications: amplitude shiftkeying (a), on off. keying (b), and frequency shift keying (c). These waveforms are coherent. s the binary state.
Metrics for Digital Modulation • Power Efficiency - Ability of a modulation technique to preserve the fidelity of the digital message at low power levels - Designer can increase noise immunity by increasing signal power - Power efficiency is a measure of how much signal power should be increased to achieve a particular BER for a given
20_comp.dvi. Comparison of digital modulation systems. Degree of channel linearity. Channel delay distortion. The three factors that influence the choice of digital modulation system are. Channel fading. Bandwidth efficiency: the number of bits per second that can be. transmitted per Hertz of channel bandwidth.
Equation 2-5 can be simplified and rearranged to express the number of conditions possible with N bits as. 2N=M. (2.6) For example, with one bit, only 21 = 2 conditions are possible. With two bits, 22 = 4 conditions are possible, with three bits, 23 = 8 conditions are possible, and so on.
Quadrature Amplitude Modulation Matched Filter. • In order to detect a signal at the receiver, a linear filter that is designed to provide the maximum output SNR in AWGN for a given symbol waveform is used. This filter is called a "matched filter" (section 3.2.2) r(t) y(t) (SNR)max. Matched Filter.
specific digital modulation method for a practical application represents a compromise among cost and performance objectives. The purpose of this paper is to identify important design variables of digital modulators and to discuss the manner in which they influence cost and performance. In particular, we derive formulas that show the variation of
Modulation and Demodulation Introduction A communication system that sends information between two locations consists of a transmitter, channel, and receiver as illustrated in Figure 1. The channel refers to the physical medium carrying the information signal (voice, video, data etc.) from one location to another.
First considers the three basic forms of digital modulation: amplitude shift-keying, frequency -shift keying, and phase-shift keying. Compares binary modulation systems, in terms of power efficiency and spectrum efficiency. Explains the principle of quadrature modulation used with M-ary PSK.
This chapter considers digital modulation techniques that are of importance to wireless communications. It presents a general mathematical model of a digital modulator and discusses the representation of the generated waveforms via an orthonormal basis and estimation of their spectral occupancy. Next, a number of single-carrier (SC) modulation ...
3. MODULATION TECHNIQUES Different modulation techniques that can be used in the LTE systems are given below: 3.1 BPSK Phase shift keying is the digital modulation technique in which data is transmitted by changing the phase of the carrier wave. BPSK is the simplest form of the PSK (which is also
PTER 5Digital modulation techniques Modulation is defined as the process by which some characteristics of a carrier is vari. d in accordance with a modulating wave. In digital communications, the modulating wave consists of binary data or an M-ary encoded version o. it and the carrier is sinusoidal wave. Different Shift keying methods that are u.
of digital modulation used in many communications systems today. Emphasis is placed on explaining the t. adeoffs that are made to optimize efficiencies in system design.Most communications systems fall into one of three cat. gories: bandwidth efficient, power efficient, or cost efficient. Bandwidth efficiency describes the ability of a.
Key focus: Compare Performance and spectral efficiency of bandwidth-efficient digital modulation techniques (BPSK,QPSK and QAM) on their theoretical BER over AWGN.. More detailed analysis of Shannon's theorem and Channel capacity is available in the following book Wireless Communication Systems in Matlab (second edition), ISBN: 979-8648350779 available in ebook (PDF) format and Paperback ...
Digital Modulation Theory for an AWGN Channel. Binary Modulation. M-ary Modulation. The Digital Modulation System. Examples of Digital Modulations. Comparison of Digital Modulation Systems. Advanced Digital Modulation Techniques. Digital Transmission of Analog Signals. Problems. References
Digital modulation techniques - Free download as Powerpoint Presentation (.ppt / .pptx), PDF File (.pdf), Text File (.txt) or view presentation slides online. This document provides an overview of several digital modulation techniques including Pulse Amplitude Modulation (PAM), Pulse Width Modulation (PWM), Pulse Position Modulation (PPM), and Pulse Code Modulation (PCM).
Chapter 4 Digital Modulation_Part 1.ppt - Free download as Powerpoint Presentation (.ppt), PDF File (.pdf), Text File (.txt) or view presentation slides online. Digital modulation techniques allow digital signals to be transmitted over analog carriers. This chapter discusses several digital modulation techniques including: - Amplitude-shift keying (ASK) which varies the amplitude of the ...
Where Eb is the transmitted signal energy per bit and Tb is bit duration the CPSK signal S(t) is expressed in the conventional form of an angle modulated signal as. 2. S ( t ) Eb. cos 2 f t ( 0) . T. c. b. The phase θ(t) is a continuous function of time which is given by. ht.
The document discusses digital modulation techniques. It begins with an introduction comparing analog and digital modulation. It then discusses digital modulation in more detail, its applications, advantages over analog systems, and important criteria. The document outlines different digital modulation techniques including ASK, FSK, PSK, and QAM. It provides examples and discusses related ...
There are mainly two types of modulation techniques which are. Analog Modulation. Digital Modulation. Analog Modulation : In Analog Modulation, both carrier and message signals are analogue waves. Digital Modulation : In Digital Modulation, only the carrier signal is analogue and the message signal is in digital form.
Comparison of digital modulation systems The three factors that influence the choice of digital modulation system are Bandwidth efficiency: the number of bits per second that can be ... Some modulation techniques are better than others if these factors are of importance on a communication channel. 2. Title:
Digital Modulation Techniques - Free download as Powerpoint Presentation (.ppt / .pptx), PDF File (.pdf), Text File (.txt) or view presentation slides online. This document discusses digital modulation techniques and is presented by a group of 5 students: Omkar Nayak, Gurpreet Singh Saini, Daivik Salian, Sumedh Nerlekar, and Anmol Sharma. It introduces the topic of digital modulation ...
The document summarizes different digital transmission techniques. It discusses modulation systems including analog modulation, digital modulation and demodulation. It describes various digital modulation techniques like FSK, PSK, ASK and MSK. It also discusses reasons for choosing different encoding techniques and provides examples of ASK, FSK and PSK modulation. The document is about a ...