VOICE CHANNEL TEST UNIT AND VOICE CHANNEL TEST CIRCUIT

Japanese Patent JP3468196

B2

PROBLEM TO BE SOLVED: To solve the problem of a conventional voice channel test unit that has had to device the configuration of the test unit because a correlator is required for testing a voice channel and a product sum arithmetic unit of the correlator requires many logic elements.
SOLUTION: The voice channel test unit testing a voice channel through which a companded voice signal is transmitted, is provided with a de-packet circuit that converts a packet in the voice channel into a continuous signal, an expansion circuit that expands the continuous signal, a voice channel test circuit that takes correlation between the expanded signal and a voice signal sent as a test signal and outputs a test result, a voice compression circuit that compresses the transmitted voice signal, and a packet circuit that assembles the compressed signal into a packet and outputs the packet to the voice channel, and the voice channel test circuit is provided with a quantization decoder that receives the test signal and quantizes the signal, a ΣΔmodulator that applies differential integration to an output of the quantization decoder in the unit of 1-bit, a correlator that takes correlation between an output of the ΣΔmodulator and the transmitted voice signal, and a comparator that compares an output of the correlator with a prescribed threshold value and the acceptance of the voice channel is discriminated on the basis of the result of comparison.

Motofumi Miyake

JP2000059397A

November 17, 2003

March 03, 2000

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NEC

G10L19/12; G10L19/00; G10L25/69; H03M3/02; H04L12/28; H04L69/40; H04M3/26; (IPC1-7): H04L29/14; G10L19/00; G10L19/12; H03M3/02; H04L12/26; H04L12/28; H04M3/26

JP2159842A
JP4363687A
JP6426976A

Johei Yamashita

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