A time compression or expansion circuit for audio signals comprises an analog to digital converter (12), a random access memory (17), a latch circuit (18), a digital to analog converter (19), a clock pulse generator (13), a counter circuit (14), a data selector (16), and a timing controller (13). The timing controller (15) is supplied with a clock pulse from the clock pulse generator (13) and a timing signal from the counter circuit (18), and produces a series of writing-in pulses and a series o...

An audio signal expander apparatus for integration into a satellite receiver for recovering audio signal transmissions carried by satellite services utilizing compressed audio signal transmission processing wherein the incoming audio signal is expanded by a ratio which varies with both the audio signal amplitude and audio signal frequency. The audio signal passes first through a low-pass filter and then through a frequency selective negative feedback circuit the output of which is filtered and d...

A parametric signal processing structure, which receives autocorrelation coefficients, produces, in an additive sparse superlattice embodiment, quantities .lambda..sub.i.sup.+, defined as (1-k.sub.m) (k.sub.m-1 +1), and in a subtractive sparse superlattice embodiment, quantities .lambda..sub.m.sup.-, defined as (1+k.sub.m) (1-k.sub.m-1), where the quantities k.sub.i correspond to the lattice predictor coefficients, or PARCORS of the signal under study. The additive and subtractive sparse superla...

A synthesizer for generating a decorrelation signal using an input signal is operative on a plurality of subband signals, wherein a subband signal includes a sequence of at least two subband samples, the sequence of the subband samples representing a bandwidth of the subband signal, which is smaller than a bandwidth of the input signal. The synthesizer includes a filter stage for filtering each subband signal using a reverberation filter to obtain a plurality of reverberated subband signals, whe...

An audio decoding device includes a playback speed change device for changing, with respect to a decoded audio signal obtained by a decoding device, the playback speed thereof; an output buffer for temporarily storing a digital audio signal outputted from the playback speed change device; a read out device for reading out the digital audio signals stored in the output buffer at predetermined time intervals; a playback speed control device for controlling the playback speed change device on the b...

Method disclosed is used for compressing the four quantization per subband tables used in MPEG1 layer 2 audio to minimize a required memory size. The method also describes how to decode the compressed tables and use the data to maximize efficiency when reading the audio samples from the input stream, de-grouping and requantization of the audio samples. The efficiency of this method is suitable for use with the implementation of a RISC/micro-processor based MPEG1 layer 2 audio decoder. Specifical...

A system and method to manipulate information in an audio decoder, the system having a demultiplexer to separate the information into packets of audio data and packet parameters, a control manager for controlling the packet parameters, and an audio decoder to manipulate the packets of audio data in response to the packet parameters. The invention also includes a control processor for passing host parameters to the control manager and a digital-to-analog converter to convert the audio information...

In a method for coding an audio signal digitized at a low sampling rate to obtain time domain audio samples. A frequency domain representation of the time domain audio samples is produced. The frequency domain representation includes successive frequency lines. These frequency lines are grouped into a plurality of scale factor bands. The successive frequency lines in a scale factor band are coded with the same scale factor. A plurality of regions is formed by grouping the scale factor bands, whe...

A device for compressing a digital audio signal, includes a device for allocating bits available for the transmission or storage of the signal, controlling means for the adaptive quantization of the signal, in order to enable a major reduction in the bit rate while at the same time preserving the quality of the starting signal to the maximum extent. The device includes means for allocating a specific number of bits for the expression of the coefficients of each frequency band of a transformed di...

A balanced multiple descriptive coder codes data in streams so that an acceptable replica of source data can be generated if either stream is lost. The balanced multiple descriptive coder may include a pair of coding branches, each branch including a coding chain and a prediction chain.