Recursively indexed differential pulse code modulation

The performance of a differential pulse code modulation (DPCM) system with a recursively indexed quantizer (RIQ) under various conditions, with first order Gauss-Markov and Laplace-Markov sources as inputs, is studied. When the predictor is matched to the input, the proposed system performs at or close to the optimum entropy constrained DPCM system. If one is willing to accept a 5 percent increase in the rate, the system is very forgiving of predictor mismatch

Real-time data compression of broadcast video signals

A non-adaptive predictor, a nonuniform quantizer, and a multi-level Huffman coder are incorporated into a differential pulse code modulation system for coding and decoding broadcast video signals in real time

An image compression technique for use on token ring networks

A low complexity technique for compression of images for transmission over local area networks is presented. The technique uses the synchronous traffic as a side channel for improving the performance of an adaptive differential pulse code modulation (ADPCM) based coder

A high-speed distortionless predictive image-compression scheme

A high-speed distortionless predictive image-compression scheme that is based on differential pulse code modulation output modeling combined with efficient source-code design is introduced. Experimental results show that this scheme achieves compression that is very close to the difference entropy of the source

Study and simulation of low rate video coding schemes

The semiannual report is included. Topics covered include communication, information science, data compression, remote sensing, color mapped images, robust coding scheme for packet video, recursively indexed differential pulse code modulation, image compression technique for use on token ring networks, and joint source/channel coder design

Adaptive, differential pulse-code modulation for speech processing

The objective of the research reported here is the design of efficient speech coders that can easily be implemented in integrated circuit hardware. Companding techniques like those introduced by M. R. Winkler, J. A. Greefkes, F. DeJager, A. Tomozawa and H. Kaneko were explored along with a large body of theory concerning the application of linear prediction to speech coding. The best features of the speech signal to be measured and coded are the overall amplitude, the resonant frequencies and dampings of the vocal cavity and the fundamental frequency of the vocal cord oscillations. Adaptive quantization was used to track variations in overall amplitude, and adaptive prediction was used to track the frequencies and dampings of the cavity resonances. No attempt was made to exploit redundancies related to the vocal cord oscillations, however. An adaptive differential pulse code modulator (i.e., an ADPCM coder) with a fixed integrator was simulated first. Later a hardware model was constructed, signal to noise measurements were taken and subjective tests conducted. When operating at 4 bits per sample, speech of a quality nearly equal to that of 7 bit log PCM was regenerated by the ADPCM encoder. At 3 bits per sample speech quality was nearly equal to 6 bit log PCM. Further improvements were achieved with the application of adaptive predictors in place of the integrator. The predictor coefficients form a vector which is adapted in a direction away from the gradient with respect to the error power. By applying this technique to the quantized signals occurring in the coder, the coefficients are derived from the quantized error signal; hence, there is no need to transmit them

The Effect of Channel Errors in the Differential Pulse-Code-Modulation Transmission of Sampled Imagery

This Paper Presents an Analysis, Simulation, and Discussion of the Effects of Communication Errors on Four-Bit Differential Pulse-Code Modulation (DPCM) Sampled Imagery. Simulations Are Presented that Describe the Effects of Inserting Periodic PCM Updates in Order to Correct Communication Errors in the DPCM Transmission of Photographic Scenes that Have Been Scanned and Sampled at the Nyquist Rate. Copyright © 1971 by the Institute of Electrical and Electronics Engineers, Inc

Speech Compression Techniques: An Overview

Speech is the natural phenomena of human for communication purpose. The aim of speech coding is to compress the speech signal to the highest possible compression ratio but maintaining user acceptability. In this paper basically two major approaches for speech compression techniques are discussed like waveform coder: pulse code modulation, adaptive differential pulse code modulation, Sub-band coding, transform coding and vocoder: linear predictive coder, formant coder/synthesis

Портативний пристрій відтворення звукових повідомленнь

Запропоновано портативний пристрій відтворення звукових повідомлень, стиснутих з використанням адаптивної диференційної імпульсно-кодової модуляції (АDРСМ) та записаних в flash-пам'ять по інтерфейсу USВ.Предложено портативное устройство воспроизведения звуковых сообщений, сжатых с использованием адаптивной дифференциальной импульсно-кодовой модуляции (АDРСМ) и записанных на flash-память по интерфейсу USВ.This article proposes a device which plays the voice, downloaded to the onboard flash memory via USB interface. Adaptive Differential Pulse Code Modulation (ADPCM) is used for sound compressing