Patent
Error detection method for sub-band coding
TLDR
In this paper, a method and apparatus for improving the quality of speech samples communicated via sub-band coding utilizing adaptive bit allocation was proposed, by providing error detection only on the adaptive bit assignment information.Abstract:
A method and apparatus is disclosed (Fig. 3) for improving the quality of speech samples communicated via sub-band coding utilizing adaptive bit allocation (Fig. 1), by providing error detection only on the adaptive bit allocation information. A first error detection code (340), such as a cyclic redundancy check (CRC), is calculated on the bit allocation parameters (330) in the transmitter (130) and sent to the receiver (180), where a second error detection code (370) is calculated based upon the reconstructed bit allocation parameters (360). The transmitted error detection code is then used to determine (380) if the received bit allocation information is correct, and if not, the frame of speech data is discarded. By protecting only the bit allocation information, additional speech frames may be salvaged from the error-prone channel, thus further increasing speech intelligibility.read more
Citations
More filters
PatentDOI
Variable rate vocoder
Jacobs Paul E,Gardner William R,Lee Chong U,Gilhousen Klein S,Lam S Katherine,Ming-Chang Tsai +5 more
TL;DR: In this paper, a variable rate coding of frames of digitized speech samples is proposed, comprising the steps of determining a level of speech activity for a frame of digitised speech samples, selecting an encoding rate from a set of rates based upon the determined level of activity within said frame, and coding said frame according to a predetermined coding format for said selected rate wherein each rate has a corresponding different coding format.
Patent
Splitterless multicarrier modem
TL;DR: In this paper, a modem for use in Digital Subscriber Line communications transmits and receives data over the local subscriber loop in common with voice information over the loop, while avoiding the need for voice/data splitters.
Patent
Method and apparatus for push and pull distribution of multimedia
TL;DR: In this article, the authors present a multimedia distribution system and method for one-way satellite broadcast with a high-bandwidth oneway satellite transmission system and a terrestrial two-way communication system, including use of the Internet and a plurality of satellite affiliate workstations.
Patent
Digital signal encoding apparatus
TL;DR: In this paper, a digital signal encoding apparatus is proposed in which input digital signals are divided into a plurality of frequency bands so that the bandwidth of each frequency band will be greater the higher the frequency band, and the allowable noise level is set for each frequency bands on the basis of the energy value of each band.
Patent
Satellite receiver/router, system, and method of use
TL;DR: In this paper, a satellite transmission system for transmission of TCP/IP compatible packets from a head end computer through a satellite uplink, an extraterrestrial satellite, a satellite downlink, and an integrated satellite receiver/router is described.
References
More filters
Journal ArticleDOI
Quantizing for minimum distortion
TL;DR: This paper discusses the problem of the minimization of the distortion of a signal by a quantizer when the number of output levels of the quantizer is fixed and an algorithm is developed to simplify their numerical solution.
Journal ArticleDOI
Quadrature mirror filter design for an arbitrary number of equal bandwidth channels
TL;DR: A key feature of this filter structure is that the number of multiplies, adds, and stored coefficients required for implementation is significantly less than those needed for the conventional QMF structure, given the same number of channels.
Patent
Method and apparatus for efficient statistical multiplexing of voice and data signals
TL;DR: The improved multiplexer described in this paper uses split band encoding across a plurality of input ports to increase the statistical advantage for compression gains but does not require a large number of input nodes to achieve its advantage.
Patent
Process for compressing data relative to voice signals and device applying said process
TL;DR: In this article, the original frequency components of a telephone band width of the voice signal sampled at 8 KHz and quantized with 12 bits are transformed into three parameters: SIGNAL data representing adaptive quantization for lower frequency (300-800 Hz) sub-bands; COEF data representing pre-emphasized parcor type coefficients for the higher frequency (800-3000 Hz) band; and, ENERGY data representing higher frequency short term energy level.
Patent
Hybrid subband coder/decoder method and apparatus
TL;DR: In this article, a hybrid vocoder is proposed to maximize the quality of transmitted voice signals while yet permitting implementation within constrained digitial memory capacity and/or constrained transmission channel bandwidth, where the subband channels of a subband coder/decoder utilize different encoding/decoding algorithms so as to maximize overall signal transmission quality using a digital signal processor having limited digital memory capability.