U.S. Philips Corporation

U.S. Philips Corpration

Rainer Dietsch

Karl Hellwig

Dietmar Lorenz

Harald Bauer

Complex coding of speech signals, as this is used, for example, in the GSM half rate speech coder, requires the use of a signal processor. On the other hand, a hands-free facility requires an arithmetic unit which adaptively calculates filter coefficients. This is only effected during speech pauses in which the speech coder is switched to a mode in which it generates codes for background noise with only little processing circuitry and expense. According to the invention, the signal processor for the coding device is therefore used for calculating the coefficients for the echo cancelling filter during speech pauses. This requires the use of not more than a single signal processor which can thus be used twice.

System for transmitting coded speech signals

A signal processor which includes a first data processing unit for processing data supplied thereto by a data bus system which operates in successive command cycles, and at least one further data processing unit operating in parallel with the first processing unit to process data supplied from the first processing unit during the command cycles. Since the further processing unit does not receive data from the bus system, that processor and still further processors can be added without requiring extension of the bus system. The parallel operation of a plurality of processing units achieves enhanced speed of computation, so that the signal processor is particularly adapted to computation of auto-correlation and cross-correlation functions and for FIR digital filtering.

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Heiligenstadt, Germany

Rainer Dietsch