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Topic: Pulse-code modulation

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Pulse-code modulation - Wikipedia, the free encyclopedia Pulse-code modulation (PCM) is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a digital (usually binary) code. PCM is used in digital telephone systems and is also the standard form for digital audio in computers and various compact disc formats. PCM was invented by the British engineer Alec Reeves in 1937 while working for the International Telephone and Telegraph in France. en.wikipedia.org /wiki/Pulse-code_modulation   (795 words)

Compression Algorithms PCM doesn`t mean any specific kind of compression, it only implies PAM (pulse amplitude modulation) - quantization by amplitude and quantization by time which means digitalization of the analog signal. In the first example code word was an binary form of quantization level (level: 3 code word: 011 see table: related with first example). It can be noticed that unlike first example the code word in general is not a binary represented quantization level, positive values of quantization levels are just binary representatives, while negative values are represented binary in different way which corresponds to the encoding process. oldwww.rasip.fer.hr /research/compress/algorithms/fund/pcm   (2082 words)

Pulse Code Modulation Pulse code modulation (to be discussed in depth later) is the heart of technology in communications in today’s digital world. The stream of pulses and non-pulse streams of 1’s and 0’s are not easily affected by interference and noise. The analog signal is represented by a series of pulses and non-pulses (1 or 0 respectively). cbdd.wsu.edu /kewlcontent/cdoutput/TR502/page13.htm   (494 words)

PCM.txt Pulse Code Modulation (PCM) unity Pulse Code Modulation is the method by which analog transmissions are converted into a digital (or pulse) format to be carried by a digital line or digital switch. So, if each vertical line in the PAM Signal illustration represents a square pulse, and each space between each line represents a certian fixed time interval, then you can see that after sampling you are left with a number of values that can be converted. Distortion can occur with square pulse sampling due to the fact that the square pulses are not the most accurate things ever created. www.nettwerked.net /PCM.txt   (959 words)

Cipher apparatus for multiplex pulse code modulation systems - Patent 4365111 In particular the code pulse corresponding to the unit's digit is used to control the generation of the cipher key pulses and since that code pulse varies in an essentially random manner the cipher key changes in a similar manner. The time or position modulation of the entire array of enciphered pulses which occur in a random manner is somewhat analogous to phase modulation of a carrier current. This negative pulse applied to the grid of the left-hand section of tube 2312 is amplified and produces a sharp pulse in the plate circuit of this section of tube 2312. www.freepatentsonline.com /4365111.html   (15962 words)

Cisco - Waveform Coding Techniques PCM is a type of coding that is called "waveform" coding because it creates a coded form of the original voice waveform. Both are implemented using eight-bit code words (256 levels, one for each quantization interval). The numerical assignment of the bit positions in the eight-bit code word to segments and the quantization levels within segments are different. www.cisco.com /warp/public/788/signalling/waveform_coding.html   (2204 words)

Pulse Code “Modulation” (PCM) Because PCM pulses are quantised, most of the effect of additive noise in the communication channel can be avoided - this is called regeneration - see fig 3.7. In PCM a sequence of quantised pulses is used to represent a number Suppose that we quantise the pulse amplitude eg to 2 or 4 levels www.itr.unisa.edu.au /cbt/comm_eng/dig_com_intro/sld012.htm   (64 words)

ADPCM Codecs Adaptive Differential Pulse Code Modulation (ADPCM) codecs are waveform codecs which instead of quantizing the speech signal directly, like PCM codecs, quantize the difference between the speech signal and a prediction that has been made of the speech signal. Code for various ADPCM codecs, as well as the G711 A-law and u-law PCM, was released into the public domain by Sun Microsystems, Inc. Its available for FTP here. Also various patches for this code, including an extension to allow it to operate at 16 kbits/s, are available from the same FTP site. www-mobile.ecs.soton.ac.uk /speech_codecs/standards/adpcm.html   (247 words)

PCM - Wikipedia, the free encyclopedia Pulse-code modulation, a way to digitally encode signals representing sound and their video couterparts Power-train control module, a computer in a car which controls the car to minimize emissions and increase fuel economy PCM is an initialism which can have different meanings: en.wikipedia.org /wiki/PCM   (119 words)

Pulse-Code Modulation The pdm pulses are then used to gate the output of a precision pulse generator that controls the number of pulses applied to a binary counter. Pulse coding can be performed in a number of ways using conventional circuitry or by means of special cathode ray coding tubes. Moreover, the pcm signal can be retransmitted, as in a multiple relay link system, as many times as desired, without the introduction of additional noise effects; that is, noise is not cumulative at relay stations as it is with other modulation systems. www.tpub.com /neets/book12/49l.htm   (1358 words)

James Mack-Pulse Code Modulation Firstly, PCM radios send what is known as a "checksum", which adds redundancy to the system by allowing the receiver to check that the data it is receiving is not corrupt. PCM and PPM are both encoding methods used for FM signals, and PCM is not a totally different transmission method like AM. Therefore, the PCM signal is affected by the same interference as a PPM signal. www.jmack.net /html/rcmodels/pulsecode   (2101 words)

Pulse Code Modulation PCM is a Time-Domain Waveform coding method and is defined within CCITT G.711, and ATT 43801. In both A-Law and Mu-Law PCM, the values used to represent the amplitude is a number between 0 and +/- 127; therefore, 8 bits are required to represent each sample (2 to the eigth power = 256). Note that the bit pattern for Mu-Law PCM is such that bit two is a zero for all eight bytes. telecom.tbi.net /digpcm.htm   (658 words)

pulse-code modulation In physics, a form of digital modulation in which microwaves or light waves (the carrier waves) are switched on and off in pulses of varying length according to a binary code. The amplitude, duration, and timing of a series of pulses are controlled in pulse-code modulation, which is relatively simple for digital data already in binary code. Morse code is a very simple example of pulse-code modulation. www.tiscali.co.uk /reference/encyclopaedia/hutchinson/m0031099.html   (233 words)

Pulse Code Modulation Encryption Unit The term "pulse code modulation" just means a bunch of 1/0 bits represented by pulses (ie, just about everything). Information on "the pulse code modulation unit" would be appreciated. Code to convert between linear and mu-law companded data is available in [6]. ftp.die.net /mirror/cryptome/pulse-code.htm   (608 words)

pulse-code modulation a form of modulation that transforms a wave-form, as an audio signal, into a binary signal in which information is conveyed by a coded order of pulses for transmission, storage on a disk, or processing by a computer. www.infoplease.com /dictionary/pulse-code+modulation   (55 words)

Pulse-Code Modulation At T1 the pulse corresponding to the least significant digit is applied and C1 charges to 16 volts. The pulse at T3 increases the charge on C1 by 16 volts to a total charge of 28 volts. A current source is used to apply the pcm pulses to an RC circuit, such as that www.tpub.com /content/neets/14184/css/14184_178.htm   (362 words)

pulse code modulation on Encyclopedia.com Pulse code modulation sound chip with 4Mb memory. Compute Signal Power with Fixed-Point Calculators -- In telecommunications devices that use pulse code modulation, it's necessary to compute the power of analog signals. Oki Electric Develops Three Models of PCM Sound Generator Chips for Mobile Phones. www.encyclopedia.com /html/x/x-pulsecod.asp   (243 words)

modulation, in communications: Pulse Modulation The modulation might vary the amplitude (PAM or pulse amplitude modulation), the duration (PDM or pulse duration modulation), or the presence of the pulses (PCM or pulse code modulation). Pulse modulation involves modulating a carrier that is a train of regularly recurrent pulses. 40 GHZ 'Optical sampler' provides advanced building block for emerging optical networking architectures; InP device supports RZ modulation, pulse shaping and OTDM - facilitating next-generation 40/160 Gbits/sec optical network architectures. www.infoplease.com /ce6/sci/A0859709.html   (267 words)

Definition: pulse-code modulation pulse-code modulation (PCM): Modulation in which a signal is sampled, and the magnitude (with respect to a fixed reference) of each sample is quantized and digitized for transmission over a common transmission medium. Note 2: PCM pulse trains may be interleaved with pulse trains from other channels. Note 1: In conventional PCM, before being digitized, the analog data may be processed (e.g., compressed), but once digitized, the PCM signal is not subjected to further processing (e.g., digital compaction) before being multiplexed into the aggregate data stream. www.atis.org /tg2k/_pulse-code_modulation.html   (123 words)

ADPCM - Adaptive Differential Pulse Code Modulation Full Name: Adaptive Differential Pulse Code Modulation Description:It is a PCM encoding technique by which analog voice samples are encoded into high-quality digital signals. Adaptive Differential Pulse Code Modulation process by which analog voice samples are encoded into high-quality digital signals. A coding method in which the difference between consecutive LPCM samples is coded--it is more bit-efficient than LPCM coding. www.auditmypc.com /acronym/ADPCM.asp   (490 words)

G.726 40, 32, 24, 16 kbit/s Adaptive differential pulse code modulation (ADPCM) G.726 makes a conversion of a 64 kbit/s A-law or mu-law pulse code modulation (PCM) channel to and from a 40, 32, 24 or 16 kbit/s channel. In the ADPCM encoder after the conversion of the A-law or mu-law PCM input signal to uniform PCM, a difference signal is obtained, by subtracting an estimate of the input signal from the input signal itself. The synchronous coding adjustment is achieved by adjusting the PCM output codes in a manner which attempts to eliminate quantizing distortion in the next ADPCM encoding stage www.vocal.com /data_sheets/g726.html   (430 words)

PCM (Pulse Code Modulation) - DVD Audio Sampling Techniques PCM or Pulse Code Modulation has become the de facto standard for digitally encoding analogue signals in both computer software and home theater audio applications. PCM's method divides an analogue voltage into regular increments and assigns a binary number (a "pulse code") to each cycle. Using PCM, any analogue waveform can be completely converted into binary code. www.hometheaterfocus.com /dvd/pcm.aspx   (433 words)

ADPCM (Adaptive Differential Pulse Code Modulation) (Linktionary term) ADPCM is a more efficient version of the digitizing method called PCM (pulse code modulation). ADPCM (Adaptive Differential Pulse Code Modulation) (Linktionary term) The difference between samples is used and the coding scale can be dynamically changed to compensate for amplitude and frequency variations. www.linktionary.com /a/adpcm.html   (183 words)

Studying 'Pulse Code Modulation'. Connected Earth is the place to continue your study of the term pulse code modulation. To progress your search for the term pulse code modulation, browsing Connected Earth's website is a good idea. Find pulse code modulation pages using Google www.connected-earth.com /content/pulse_code_modulation.html   (299 words)

New Materials Japan: Pulse code modulation sound generator large scale integrations.@ HighBeam Research Pulse code modulation sound generator large scale integrations. Oki Electric Industry Co Ltd has developed two pulse code modulation (PCM) sound generator large scale integrations (LSIs) - the ML2860 and the ML2861 - used for mobile phones and personal handyphone systems (PHS). The LSIs are compliant with the industry-standard, general musical instrument digital interface (MIDI) system level 1 and provide maximum 32-note polyphony with 16 timbres simultaneous playback. www.highbeam.com /library/doc0.asp?DOCID=1G1:82360598&refid=holomed_1   (207 words)

Differential Pulse Code Modulation In PCM, each sample of the waveform is encoded independently of all the other samples. The source code file of the MATLAB code and the output can be viewed using MATLAB. The "dpcm_demo" shows the use of DPCM to approximate a input sine wave signal and a speech signal that were sampled at 2 KHz and 44 KHz, respectively. www.ece.drexel.edu /commweb/dpcm/dpcm.html   (383 words)

Researching 'Pulse-Code Modulation'. Connected Earth is an appropriate place to carry out your investigation of the term pulse-code modulation. The presentation is a uniquely multi-media one, allowing you to switch between straightforward descriptions, more thorough research, pictures of artefacts in 3D, written or oral stories from those who used to work in the telecommunications industry, movie clips, and simple animations or interactive explanations of how technology works. As well as hunting for information that specifically answers your questions, you may decide to explore one of the nine galleries. www.connected-earth.com /content/pulse-code_modulation.html   (286 words)

Pulse Code Modulation (PCM) The ``standard'' number format for sampled audio signals is officially called Pulse Code Modulation (PCM). This term simply means that each signal sample is interpreted as a ``pulse'' (e.g., a voltage or current pulse) at a particular amplitude which is binary encoded, typically in two's complement binary fixed-point format (discussed below). When someons says they are giving you a soundfile in ``raw binary format'', they pretty much always mean (nowadays) 16-bit, two's-complement PCM data. www.technick.net /public/code/cp_dpage.php?altmenu=1&aiocp_dp=guide_dft_pulse_code_modulation   (240 words)

Pulse Code Modulation PCM digital stereo is offered on selected Sony 8mm equipment. On the Sony EV-S7000 Hi8 VCR, PCM digital stereo allows for overdubbing of high-quality audio music or other sound—while retaining a videotape’s original soundtrack. It is recorded at a position on the tape separate from the regular AFM Hi-Fi soundtrack. www.digitalvideoforless.com /pcm.htm   (126 words)

Pulse Code Modulation from FOLDOC Nearby terms: pull-down list « pull-down menu « pull media « Pulse Code Modulation » pumpkin » pumpkineer » pumpking Virtually all digital audio systems use PCM, including, CD, DAT, F1 format, 1630 format, DASH, DCC, and MD. Many people get confused because "PCM" is also slang for Sony's F1 format which stores PCM digital audio on videotape. (PCM) A method by which an audio signal is represented as digital data. foldoc.org /?Pulse+Code+Modulation   (72 words)

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