
	Where results make sense

Topic: Linear predictive coding

Related Topics

Speech coding

Speech processing

Linear prediction

Audio signal processing

Speaker recognition

PLL

Formant

RealAudio

Free software

Cheung Sha

Linear prediction

In the News (Tue 10 Nov 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Linear predictive coding - Wikipedia, the free encyclopedia
		Linear predictive coding (LPC) is a tool used mostly in audio signal processing and speech processing for representing the spectral envelope of a digital signal of speech in compressed form, using the information of a linear predictive model.
		LPC starts with the assumption that a speech signal is produced by a buzzer at the end of a tube (voiced sounds), with occasional added hissing and popping sounds (sibilants and plosive sounds).
		LPC analyzes the speech signal by estimating the formants, removing their effects from the speech signal, and estimating the intensity and frequency of the remaining buzz.
	en.wikipedia.org /wiki/Linear_predictive_coding (791 words)

	Linear Predictive Coding (Site not responding. Last check: 2007-10-21)
		LPC starts with the assumption that a speech signal is produced by a buzzer at the end of a tube.
		LPC synthesizes the speech signal by reversing the process: use the residue to create a source signal, use the formants to create a filter (which represents the tube), and run the source through the filter, resulting in speech.
		Linear prediction is a mathematical operation where future values of digital signal is estimated as a linear function of previous samples.
	www.cclinf.polito.it /~s99290/lpc.html (602 words)

	Speech Coding With Linear Predictive Coding (Site not responding. Last check: 2007-10-21)
		Linear Predictive Coding is one possible technique of analyzing and synthesizing human speech.
		The principle behind the use of LPC is to minimize the sum of the squared differences between the original speech signal and the estimated speech signal over a finite duration.
		Shifting to the voice excited LPC technique, the pitch and the binary choice in the method of excitation is dropped (7 bits per frame) but all the errors have to be sent.
	www.dspexperts.com /dsp/projects/lpc (4881 words)

	Block adaptive linear predictive coding with adaptive gain and bias - United States Patent 4,885,636
		A block adaptive linear predictive coding method for encoding a digital image is improved by calculating the mean of the error signals in each block, and selecting a quantizer for each block, using the calculated signal and the calculated mean, from a set of minimum square error two-variable quantizers.
		LPC refers to the general class of coding techniques in which the difference or error between a given signal value and a linear prediction of the signal value, based on correlated signal values, is coded.
		Predictions are made (18) for the pixel values in each block using the previous coded pixel values on the line and coded pixel values on the previous line.
	xrint.com /patents/us/4885636 (4630 words)

	9.2. Linear Predictive Coding
		LPC is another method of separating out the effects of source and filter from a speech signal; similar in intention to cepstral analysis but using quite different methods.
		The result of LPC analysis then is a set of coefficients a[1..k] and an error signal e[n], the error signal will be as small as possible and represents the difference between the predicted signal and the original.
		LPC coefficients can also be used to derive cepstral coefficients and area functions as described in the remainder of Chapter 6.
	www.ics.mq.edu.au /~cassidy/comp449/html/ch09s02.html (1397 words)

	Linear Predictive Coding (LPC) (Site not responding. Last check: 2007-10-21)
		Linear Predictive Coding is one of the most powerful speech analysis techniques, and one of the most useful methods for encoding good quality speech at a low bit rate.
		Basic Principles LPC starts with the assumption that the speech signal is produced by a buzzer at the end of a tube.
		The vocal tract (the throat and mouth) forms the tube, which is characterized by its resonances, which are called LPC analyzes the speech signal by estimating the formants, removing their effects from the speech signal, and estimating the intensity and frequency of the remaining buzz.
	www.student.chula.ac.th /~47704705/2-1.html (237 words)

	Seminar - Voice Coding Algorithms
		Pulse Code Modulation and Sub Band Coding are examples of waveform coding algorithms while Linear Predictive Coding is an example of an algorithm that models the vocal tract.
		In the LPC algorithm, the filter coefficients and the excitation type are all that is needed to be transmitted which can be significantly less than the amount of information need to be transmitted for PCM methods.
		High quality coding with the G.722 wideband speech coder is provided by a fixed bit allocation, where the low and high sub-bands ADPCM coders use a 6 bits/sample and 2 bits/sample quantizer, respectively.
	www.nextgendc.com /seminar_voice_coding.htm (1683 words)

	Heritage (Site not responding. Last check: 2007-10-21)
		In 1967, B. Atal, Schroeder, and S. Hanauer conceived the method of linear prediction as an improvement for characterizing the amplitude spectrum of speech.
		Also subsequently, the linear prediction method was applied by Atal to a vocoder method in which multiple pulses in successive time intervals were used to optimally describe the residual prediction error signal.
		When the redundancy is separated or extracted from speech, what is left is the residual signal which can be represented by several prevalent models: buzz-hiss (see Vocoder), multiple pulse or multiple pulse sequence, random code sequence (i.e., code excitation), or even a fake process, which only retains the critical statistical property of the residual.
	www.bell-labs.com /org/1133/Heritage/Lpc (301 words)

	Linear Predictive Coding (LPC)
		Linear Predictive Coding (LPC) is one of the most powerful speech analysis techniques, and one of the most useful methods for encoding good quality speech at a low bit rate.
		This means that for each frame, the LPC encoder must decide if the sound source is buzz or hiss; if buzz, estimate the frequency; in either case, estimate the intensity; and encode the information so that the decoder can undo all these steps.
		Linear Predictive Coding is a powerful speech analysis technique for representing speech for low bit rate transmission or storage.
	www.otolith.com /otolith/olt/lpc.html (1334 words)

	Linear predictive coding
		The analysis/synthesis method known as linear predictive coding (LPC) was
		The LPC implements a type of vocoder [10], which is an analysis/synthesis
		The basic assumption behind LPC is the correlation between the n-th sample
	www.faqs.org /docs/sp/sp-96.html (324 words)

	LPC - TheBestLinks.com - Lpc, Abbreviation, Microsoft, Linear predictive coding, ... (Site not responding. Last check: 2007-10-21)
		LPC is also an abbreviation for linear predictive coding.
		LPC is also an abbreviation for Local Procedure Call, a cross-address space communication mechanism used by Microsoft's Windows NT.
		LPC is also an abbreviation for Low Pin Count.
	www.thebestlinks.com /Lpc.html (136 words)

	Adaptive predictive coding - Wikipedia, the free encyclopedia
		Adaptive predictive coding (APC) is a narrowband analog-to-digital conversion that uses a one-level or multilevel sampling system in which the value of the signal at each sampling instant is predicted according to a linear function of the past values of the quantized signals.
		APC is related to linear predictive coding (LPC) in that both use adaptive predictors.
		However, APC uses fewer prediction coefficients, thus requiring a higher sampling rate than LPC.
	en.wikipedia.org /wiki/Adaptive_predictive_coding (146 words)

	Linear Predictive Coding of Speech
		The linear-prediction voice model is best classified as a parametric, spectral, source-filter model, in which the short-time spectrum is decomposed into a flat excitation spectrum multiplied by a smooth spectral envelope capturing primarily vocal formants.
		When applying LPC to audio at high sampling rates, it is important to carry out some kind of auditory frequency warp is a non-uniform scaling of frequency.
		LPC demands that the vocal tract be driven by a flat spectrum--either an impulse (or low-pitched impulse train) or white noise--which is not physically accurate.
	ccrma-www.stanford.edu /~jos/smithbook/Linear_Predictive_Coding_Speech.html (425 words)

	LPC Tutorial
		Linear Predictive Coding performs a spectral analysis of an input signal by sectioning the signal into frames.
		The name Linear Predictive Coding is derived from the fact that output samples are predicted by a linear combination of filter parameters and previous samples.
		An LPC analysis consists of a frame number, the root-mean-square (rms) of the residual of analysis (krmsr), the rms of the original signal (krmso), the normalized error signal (kerr), and the pitch in Hertz (kcps) [See Csound manual].
	www-personal.umich.edu /~msimoni/LPC-Tutorial.html (657 words)

	Low Complexity CELP Speech Coder (Site not responding. Last check: 2007-10-21)
		Code excited linear predictive (CELP) coding is a well-known technique that synthesizes speech using encoded excitation information to excite a linear predictive coding (LPC) filter.
		LPC analysis is performed on input speech to determine the LPC filter parameters.
		The analysis includes comparing the outputs of the LPC filter when it is excited by the various candidate vectors from the table or codebook.
	www.isr.umd.edu /ISR/accomplishments/007_CELP (1023 words)

	Heritage (Site not responding. Last check: 2007-10-21)
		Analysis-by-Synthesis linear predictive coding was found to be an efficient approach towards speech coding.
		Although originally thought to be complex to be usable in practical speech coding systems, the next 10 years of research by the speech coding community resulted in many innovative solutions for solving the complexity problem.
		As a result almost all modern speech coding standards as used in cellular and internet communications are based on the CELP coding paradigm.
	www.bell-labs.com /org/1133/Heritage/Celp (119 words)

	second_draft (Site not responding. Last check: 2007-10-21)
		Linear Predictive Coding (LPC) is one possible technique of analyzing and synthesizing human speech.
		Subband coding is mostly utilized in the medium to high bit rate applications of speech coding.
		The bit rate for a plain LPC vocoder is shown in Table 1 and the bit rate for a voice-excited LPC vocoder with DCT is printed in Table 2.
	home.comcast.net /~chaspong/second_draft.html (2644 words)

	Instructions for Using MiXViews
		A portion of an open LPC datafile must be selected first, followed by the selection of a region in a sound to be filtered.
		LPC analysis, which originally was used for statistical analysis, proved useful in computer music because of its ability to extract and store time-varying formant information.
		In the LPC analysis command, the number of poles specifies the accuracy of the analysis: the greater the number of poles, the more precisely the format regions will be captured.
	www.create.ucsb.edu /~doug/htmls/mxv-manual.html (7066 words)

	Untitled Document (Site not responding. Last check: 2007-10-21)
		The basic idea behind linear predictive analyses is that a speech sample can be approximated as a linear combination of past speech samples.
		The basic linear prediction idea leads to a set of analyses technique that can be used to estimate parameters of a speech model.
		Actually, rather than using the linear prediction coefficients ai, we could have used the reflection coefficients which are obtained in the Levinson Recursion algorithm.
	plaza.ufl.edu /vigneshk/introduction.html (380 words)

	Untitled Document
		The coder is based on the principles of linear prediction analysis-by-synthesis coding and attempts to minimize a perceptually weighted error signal.
		The unquantized LPC coefficients are used to construct the short-term perceptual weighting filter, which is used to filter the entire frame and to obtain the perceptually weighted speech signal.
		The combination of the LPC synthesis filter, the formant perceptual weighting filter, and the harmonic noise shaping filter is used to create an impulse response.
	www.uic.edu /classes/ece/ece434/chapter_file/Chapter5_files/Speech.htm (2058 words)

	MMSP Lab - Paper Abstracts (1986) (Site not responding. Last check: 2007-10-21)
		Delayed decision coding together with noise masking theory is used in a code excited linear predictive speech coding system.
		Prediction errors are coded in blocks of N samples.
		A new algorithm that estimates the pitch period is coupled with the covariance formulation of determining the predictor coefficients.
	www.tsp.ece.mcgill.ca /Kabal/papers/P1986.html (499 words)

	[No title]
		Firstly, linear predictive coding (LPC) is explored as a potential method for extracting partial reflection coefficients (PARCORs) as well as an error signal from a given audio input.
		As mentioned, the synthesis filter, H(z), in linear predictive coding is represented by an all-pole filter, and the response of this filter in the spectral domain may be expressed as EMBED Equation.3 (2) where A(z) is the prediction filter.
		This is the heart of linear predictive coding, and is given by EMBED Equation.3 (3) What happens, then, in linear predictive analysis is that the predictor, A(z), generates an estimate signal, EMBED Equation.3 , from the original input signal.
	www.music.mcgill.ca /~wes/school/605/ProjectSummary (2057 words)

	Speak & Spell assignment (12.4KA1)
		Originally, linear predictive coding was designed as a compression technique for speech.
		Despite not being designed for the purpose, linear predictive coding is also readily adaptable to speech synthesis.
		The voice synthesizer performs reverse linear predictive coding on this data to generate the sound.
	www.cee.hw.ac.uk /~cmj/projects/Speak/operation/operation.html (587 words)

	Assignment 4, due Tuesday, March 4, 1997
		LPC works best with speech, and at lower sampling rates.
		It does a pitch analysis of the sound, an lpc analysis, stabilizes the lpc analysis, merges the pitch and lpc analyses, and does a flat resynthesis of the sound.
		A program called lpcplot will allow you to doctor the details of an lpc data set, changing, smoothing and replacing values for pitches, and voiced unvoiced flags.
	www.cs.princeton.edu /courses/archive/spr99/cs325/lpc.html (901 words)

Try your search on: Qwika (all wikis)