Capacity of pulseposition modulation ppm on gaussian. Principles of noise random variables, white noise, shot, thermal and flicker noise, noise in cascade amplifiers pulse. Analog communication pulse modulation tutorialspoint. There are many modulation techniques, which are classified according to the type of modulation employed. No information is lost, but the energy is redistributed in the frequency domain. It is primarily useful for optical communications systems, which tend to have little or no multipath interference. Pulse position modulated ppm ground receiver design for. Pulse width modulation pwm is a modulation technique, which converts an analog signal into a digital signal for transmission. Pulse amplitude modulation, pulse width modulation, pulse. In singlechannel efield sensing, the carrier we transmit is m, the sensed value is a, and the noise is n vectors. Using matlab mfile and simulink to implement fm modulation and demodulation. In particular, all telephone modems faster than 300 bits use quadrature amplitude modulation qam. The ppmwc signal is generated by summing the ppm signal and the pll reference 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. Modulation is a technique in which message signal is transmitted to the receiver with the help of carrier signal. To understand the methods of measuring and adjusting the pcm demodulation circuit. An enhanced pulse position modulation ppm uni scholarworks.
Pulse position modulation ppm is a form of signal modulation in which m message bits are. To study and perform pulse position modulation and demodulation. Pulse modulation modulation digital signal free 30. Pulse amplitude modulation is the basic form of pulse modulation. It is used in fibre optics and ir infrared remote controls where there is a lack of interference, it is a technique that uses pulses of the same breath and height but is displaced in time from some base position according to the. This paper presents the modulation and demodulation of pulse position modulation with carrier. It is another type of ptm, where the amplitude and width of the pulses are kept constant and only the position of the pulses is varied. Index terms ultra wideband, pulse position modulation, on off key modulation, multipath.
To study and perform pulse position 6 to study and perform pulse code modulation and demodulation. Here in modulation, we combine both carrier signal and message signal. The pulse may take any real voltage value that is proportional to the value of the original waveform. The amplitude of the fm signal is constant at all times and is independent of the modulation signal. The ideal modulated signal should have a minimum euclidean distance of 2. 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. Pulse position modulation ppm is an analog modulating scheme in which the amplitude and width of the pulses are kept constant, while the position of each pulse, with reference to the position of a reference pulse varies according to the instantaneous sampled value of the message signal. We use modulation technique to alter signals in time and frequency to accomplish desired objectives. Sampling theorem and pulse amplitude modulation pam reference stremler, communication systems, chapter 3. Pollara1 this article computes the capacity of various idealized softdecision channels modeling an optical channel using an avalanche photodiode detector apd and pulse position modulation ppm. Pulse position modulation ppm is an analog modulation scheme in which, the amplitude and the width of the pulses are kept constant, while the position of each pulse, with reference to the position of a reference pulse varies according to the instantaneous sampled value of the message signal. The pulse position modulation ppm is a modulation technique designed to achieve the goals like simple transmitter and receiver circuitry, noise performance, constant bandwidth and the power efficiency and constant transmitter power. Pcm is in binary form, so there will be only two possible states high and low0 and 1.
Introduction to modulation and demodulation modulation. Before we study in detail about pam lets know the concepts of modulation. Vectors and modulation cse 466 interfacing 3 spose m and n are orthogonal unit vectors. Each channel sharing scheme a set of basis vectors. Introduction also sometimes known as pulsephase modulation the amplitude and width of the pulse is kept constant in the system the position of each pulse, in relation to the position of a recurrent reference pulse, is varied by each instantaneous sampled value of the modulating wave cont often used in optical communication, such as fiber optics, in which there is little multipath way. Aug 17, 2017 for the love of physics walter lewin may 16, 2011 duration. Modulation and demodulation of pulse position modulation with carrier l. The original waveform amplitude is quantized with a resulting loss of information. A signal is pulse code modulated to convert its analog information into a binary sequence, i. To study and perform pulse width modulation and demodulation. This lab introduces students to communications theory with amplitude modulation and demodulation. In pulse position modulation the amplitude of the pulse is kept constant as in the case of the fm and pwm to avoid noise interference. Pulse modulation definition of pulse modulation by the. Dsbsc modulation at a carrier frequency, kc, specified by the student.
Modulation and demodulation principle borrow from radio telecommunication take a wide band signal few hz to khz modulate it with a single frequency the carrier signal which is the frequency associated to a given station emit the signal given the station frequency, a receiver follows a. A system of modulation in which pulses are altered and controlled in order to represent the message to be communicated. The obtained simulation and experimental results confirm well with the given analysis. Pulse position 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. First, just consider a simple example of throwing a paper for a much far distancecould u do that with ease. For the love of physics walter lewin may 16, 2011 duration. Application note of pampulse amplitude modulation signal. Cr1 is the input diode which allows capacitor c1 to charge to the peak value of the pam input pulse. 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. Pulse modulation modulation digital signal free 30day. Figure 321 includes a simplified circuit view a for this demodulator and its waveforms views b and c. Additional info pulse wave modulation pam, pwm, ppm do not convert baseband msg signal to bandpass, whereas continuos wave modulation am, fm, pm converts baseband into bandpass msg signal.
Pulse position modulation thus as the trailing edges of the pwm. Pulse amplitude, pulse width and pulse position modulation and demodulation lab experiment vtu duration. Modulation pam, pulse duration modulation pdm also known as pulse width modulation pwm, and pulse position modulation ppm. Introduction ground reception technology for deep space optical communications is being developed at jpl in order to service future nasa missions. Apr 07, 2015 pulse width modulation pwm is a modulation technique, which converts an analog signal into a digital signal for transmission. Amplitude modulation of the vibration signatures is common and we have seen how this causes sidebands to be present in the frequency domain.
Pulse amplitude modulation pam theory of and its applications. This is repeated every t seconds, such that the transmitted bit rate is bits per second. Electronics a type of modulation in which a train of pulses is used as the carrier wave, one or more of its parameters, such as amplitude, being modulated or modified in order to carry. Demodulation channel decoding is the corresponding process at the receiver of converting the received waveform into a. Large aperture 10 m diameter telescopes will be used to. Among the types of modulation techniques, the main classification is continuouswave modulation and pulse modulation. The proposed scheme is examined by using computer simulation and experiment. Wardkein1 1department of telecommunication engineering, faculty of engineering 2faculty of information technology king mongkuts institute of technology ladkrabang, ladkrabang, bangkok, thailand 10520. Introduction also sometimes known as pulse phase modulation the amplitude and width of the pulse is kept constant in the system the position of each pulse, in relation to the position of a recurrent reference pulse, is varied by each instantaneous sampled value of the modulating wave cont often used in optical communication, such as fiber optics, in which there is little multipath way. The amplitude of the carrier remains constant phase modulation pm another form of analog modulation technique which we will not discuss. Pulse amplitude modulation pam, quadrature amplitude modulation qam 12. It is a modulation system in which the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the signal at the instant of sampling.
Then, students will use labview to program an am demodulator and use it to explore and visualize the. Modulation and demodulation of pulse position modulation with. Students will explore the mathematical theory behind amplitude modulation and use the analog discovery 2 to visualize the effects of amplitude modulation in the time and frequency domains. Capacityapproaching codes demodulation line coding modem anm pom pam pcm pdm pwm m ofdm fdm multiplexing v t e. Pulseamplitude modulation is widely used in modulating signal transmission of digital data, with nonbaseband applications having been largely replaced by pulsecode modulation, and, more recently, by pulseposition modulation. 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. The modulator the modulator outputs two files, the first with the modulated signal exactly n real elements long and the.
Modulation allows us to transmit multiple signals in the same medium i. The phasedev argument is the phase deviation of the modulated signal, in radians. We can also get back our analog signal by demodulation. Pulse amplitude modulation is a technique in which the amplitude of each pulse is controlled by the instantaneous amplitude of the modulation signal. Pulse position modulation ppm is a signal modulation used for both analog and digital signal transmissions. 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. But if u use a stone or any other object to wind the paper, then the paper reaches more t. Nov 06, 20 pulse amplitude, pulse width and pulse position modulation and demodulation lab experiment vtu duration. Capacity of pulse position modulation ppm on gaussian and webb channels s. Pulse amplitude demodulation peak detection is used to detect pam. A modulation technique that allows variation in the position of the pulses according to the amplitude of the sampled modulating signal is known as pulse position modulation ppm. 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. Frequency division multiplexing, fdma amplitude modulation and demodulation.
Pulseposition modulation ppm is a form of signal modulation in which m message bits are. The information is conveyed via changing position of pulses. Pulse position modulation definition of pulse position. Pulseposition modulation ppm is a signal modulation used for both analog and digital signal transmissions. Digital communication using chaoticpulseposition modulation. In this paper, we combine all the optimal and nearoptimal optical demodulation receivers that have been found to date under one general class of structured receiversthe conditional pulse nulling cpn. Investigation of the pulse time modulation techniques for. A pulsemodulated signal in radar may be detected by a simple circuit that detects the presence of rf energy. Introduction frequency modulation is a form of modulation, which represents information as. Increased data rates accompanied by a reduction in payload mass, volume and power, motivate. In this modulation, the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the modulating signal. Modulation and demodulation of pulse position modulation. Ook modulation, in the article an energy adaptive demodulation for high data rates with impulse radio.
Pulse position modulation ppm is an analog modulating scheme in which the amplitude and width of the pulses are kept constant, while the position of each pulse, with reference to the position of a reference pulse varies according to. Circuits that are capable of this were covered in this chapter in the cw detection discussion. Pulse amplitude modulation is widely used in modulating signal transmission of digital data, with nonbaseband applications having been largely replaced by pulse code modulation, and, more recently, by pulse position modulation. Therefore all the ppm pulses have the same amplitude and width.
The continuous wave modulation techniques are further divided into amplitude modulation and angle modulation. 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. You may get the doubt that what is the need of modulation. Of them all, the digital modulation technique used is pulse code modulation pcm. Pulse width modulation and in position ppm, pulse position. Sampling theorem determines the necessary conditions which allow us to change an analog signal to a discrete one. Pulse code modulation is a method that is used to convert an analog signal into a digital signal so that a modified analog signal can be transmitted through the digital communication network. Pulse position modulation, sometimes known as pulse phase modulation is used for digital signal transition.
Sampling theorem and pulse amplitude modulation pam. A continuouswave goes on continuously without any intervals and it is the baseband message signal, which contains the information. Pulse position modulation ppm provides a means of using high peak power lasers for transmitting communications signals from planetary spacecraft to earthbased receiving stations. To understand the theory of pcm demodulation circuit. Pulse position modulation and demodulation trainer youtube.
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