Nnpulse position modulation demodulation pdf free download

Modulation is broadly classified into two categories namely analog modulation a. Communications contents introduction to communication systems analogue modulation am, dsbsc, vsb, ssb, fm, pm, narrow band fm, pll demodulators, and fll loops sampling systems time and frequency division multiplexing systems, nyquist principle, pam, ppm, and pwm. Modulation and demodulation of pulse position modulation. A new modified mppm for highspeed wireless optical. Demonstration with professor sandy hill from the university of massachusetts at amherst. Optical wireless communications, or, freespace optics. Each receiver can then apply a suitable filter to extract the baseband signal of interest to it. Among the types of modulation techniques, the main classification is continuouswave modulation and pulse modulation. Demodulation is extracting the original informationbearing signal from a carrier wave. The goal of this experiment is to become familiar with fm modulation and demodulation. The mdsr was also tested with wspr and jt65hf with excellent results. When input noise power is quite large we would be inclined to use fm and allows a sacrifice of bandwidth for the sake of improved. The receiving end is known as demodulation or detection. Pdf orthogonal spacetime block codes for binary pulse.

Demodulation channel decoding is the corresponding process at the receiver of converting the received waveform into a. The ideal modulated signal should have a minimum euclidean distance of 2. Carrier is usually a sinusoidal signal of high frequency. Pulse position modulation and demodulation trainer youtube. Using the free mdsr and rfseismograph software and our inexpensive lif interface pcb it is easy to do. Pulse position modulation for fso systems institut fresnel. You may get the doubt that what is the need of modulation. Index termspulse position modulation, ppm, synchroniza tion, error correction, selfsynchronizing code, commafree code, combinatorial design, optical. First, just consider a simple example of throwing a paper for a much far distancecould u do that with ease.

Follow 18 views last 30 days malek kashou on 26 dec 2012. There are different types of modulation and so are demodulators. Modulation is a technique in which message signal is transmitted to the receiver with the help of carrier signal. Pwm converts an audio signal into a sequence of pulses having constant amplitude, but the width is proportional to amplitude of an audio signal. To study and perform pulse position 6 to study and perform pulse code modulation and demodulation. In pulse position modulation, both the pulse amplitude and pulse duration are held constant but the position of the pulse is varied. An optimized scheme of pulse symmetrical position orthogonal spacetime block codes pspostbc is proposed and applied with mpulse positions modulation mppm without the use of a complex. Pulse amplitude modulation pulse width modulation pulse position modulation pulse code modulation pulse modulation the process of transmitting signals in the form of pulses discontinuous signals by using special techniques. Pulse width modulation pwm is a modulation technique, which converts an analog signal into a digital signal for transmission. Experimental training board has been designed specifically for the study of pulse position modulation and demodulation. Direct detection receiver and the helstrom bound mary ppm encodes digital data by positioning a. A demodulator is an electronic circuit or computer program in a softwaredefined radio that is used to recover the information content from the modulated carrier wave. Wireless optical communication woc, also known as free space optical fso.

The obtained simulation and experimental results confirm well with the given analysis. The pulse may take any real voltage value that is proportional to the value of the original waveform. No information is lost, but the energy is redistributed in the frequency domain. As the baseband signals have low frequencies with low power, therefore, they cannot be transmitted over long distance. The signal output from a demodulator may represent sound an. This expression is correct provided that we keep in the range. Baseband signals are transmitted without modulation i. The continuous wave modulation techniques are further divided into amplitude modulation and angle modulation. All the additional monitoring of 24h every day allows the creation of a very good understanding of your site, antenna and achievable propagation. These three pm techniques are classified as analog pulse modulation, which accounts for the fact that the respective pulse characteristics are modified with the sample value of the message signal. There are many types of modulation so there are many types of demodulators.

Modulation pam, pulse duration modulation pdm also known as pulse width modulation pwm, and pulse position modulation ppm. In this modulation, the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the modulating signal. It is primarily useful for optical communications systems, which tend to have little or no multipath interference. 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. Abstractwe consider the problem of demodulating mary optical ppm pulseposition modulation waveforms, and propose a structured receiver whose mean. Modulationdemodulation process facilitates channel assignment and. Abstractfor terrestrial free space optical fso sys tems, we investigate the. Pulse amplitude modulation is the basic form of pulse modulation. Fm modulation and demodulation electrical and computer. Here in modulation, we combine both carrier signal and message signal. Explain generation and demodulation of pam, ppm and pwm.

Modulation is the process of changing the characteristics of the carrier signal in accordance with the instantaneous values of the modulating signal message signal. If the received carrier phase is assumed to be constant, each of the seven reference values will have to be shifted only once at the beginning of the simulation. To understand the methods of measuring and adjusting the pcm demodulation circuit. We consider the problem of demodulating mary optical ppm pulseposition modulation waveforms, and propose a structured receiver whose mean. Modulation allows us to transmit multiple signals in the same medium i. To study pulse position modulation and demodulation. Pulse modulation modulation digital signal free 30. Pulse amplitude, pulse width and pulse position modulation and demodulation lab experiment vtu duration. Fm demodulation using pll in fm modulation when the bandwidth becomes so large that the input noise power is relatively large, the performance of the fm system degrades rapidly and the system exhibits a threshold. This is repeated every t seconds, such that the transmitted bit rate is bits per second.

Capacityapproaching codes demodulation line coding modem anm pom pam pcm pdm pwm m ofdm fdm multiplexing v t e. Pulseposition modulation ppm is a form of signal modulation in which m message bits are. Each channel sharing scheme a set of basis vectors. In a noisefree environment, the arrival time of chaotic pulses. With 6 bands recoded at once it is possible to catch. Demodulation is defined as extracting the original informationcarrying signal from a modulated carrier wave. Pulse modulation definition is modulation of a radio wave or signal by pulses. Chapter 6 covers classical material on optimum demodulation for mary signaling in the pres. The code of psk modulation and demodulation has been developed using matlab according to conventional theory. Practical experience on this board carries great educative value for science and engineering students. Frequency modulation and demodulation file exchange. The ramp will attain different heights in each cycle since the widths are different and the heights attained are directly proportional to the pulse width and in turn the amplitude of the message signal.

This insight is useful because the noisefree behavior. A typical f c for lowrate telephone line modems is 1800 hz approximate center of 300 3400 band, and for 1200 baud signaling 1200 pulses per. If poss explain me the working of each syntax in the program. Rf modulation and demodulation of audio and video signals. A pulsemodulated signal in radar may be detected by a simple circuit that detects the presence of rf energy. As a result, the gate voltage assuming the two gate. In early days, the communication system is mostly using the analog signal to transmit signals. Using this training board one can know the specialized techniques of pulse position modulation and demodulation. Pulseposition modulation ppm is a form of signal modulation in which m message bits are encoded by transmitting a single pulse in one of possible required time shifts. Coded multipulse pulseposition modulation for freespace. Digital communication using chaoticpulseposition modulation. In singlechannel efield sensing, the carrier we transmit is m, the sensed value is a, and the noise is n vectors. But if u use a stone or any other object to wind the paper, then the paper reaches more t.

Rf modulation and demodulation of audio and video signals any information that is broadcast over the airwaves is broadcast via what are known as radio waves. Rc audio generator, oscilloscope, and spectrum analyzer demonstrations with speech and radio. Modulation is the process of impressing a lowfrequency information signal baseband signal onto a higher frequency carrier signal modulation is done to bring information signals up to. Pulse modulation definition of pulse modulation by. Principles of noise random variables, white noise, shot, thermal and flicker noise, noise in cascade amplifiers pulse.

The ppmwc signal is generated by summing the ppm signal and the pll reference signal. For more info please visit our website or join the yahoo user group. The idea is simple, though the notion that it can be used to modulate. Before we study in detail about pam lets know the concepts of modulation. A continuouswave goes on continuously without any intervals and it is the baseband message signal, which contains the information. Frequency modulation fm is a process in which the carrier frequency is varied by the amplitude of the modulating signal i. To understand the theory of pcm demodulation circuit. Circuits that are capable of this were covered in this chapter in the cw detection discussion. Pulseposition modulation ppm is a signal modulation used for both analog and digital signal transmissions. Pulse position modulation ppm is a form of signal modulation in which m message bits are. This paper presents the modulation and demodulation of pulse position modulation with carrier.

In analog applications, the carrier frequency is varied in direct proportion to changes in the amplitude of an input signal. Frequency modulation is a form of modulation, which represents information as variations in the instantaneous frequency of a carrier wave. The original waveform amplitude is quantized with a resulting loss of information. Radio frequency rf is the rate of oscillation or frequency at which a particular type of information is transmitted over the airwaves. This method is widely used for optical communication systems such as optic fiber and ir remote controls, where efficiency is required and little or no external interference occurs. The proposed scheme is examined by using computer simulation and experiment.

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