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Primary Examiner: Claffy, Kathleen H.
Assistant Examiner: Kemeny, E. S.
Attorney: Armstrong, Nikaido, Marmelstein & Kubovcik

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Title: Frequency band compression of FDM using time expansion

Abstract: A frequency band compression method, using Time Compression, for use with a frequency division multiplex (FDM) signal carrying voice signal. On the transmission end, the multiplexed signal is divided into a plurality of time segments, each segment having a certain duration, then deleting a part of the each segment and time-expanding the remaining part of the segment by a sawtooth variable delay, thus lowering the frequency of the signal to a predetermined ratio. On the receive end, the signal segments are compressed by a corresponding variable delay, thus making the received frequency higher and reproducing the original multiplexed voice signals.

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Inventors: Yuguchi, Hiroshi (Fuchu, JP)
Nunokawa, Makoto (Kawasaki, JP)
Nakai, Taiichiro (Fujisawa, JP)

Application Number: 846832
Filing Date: 1977-10-31
Publication_date: 1979-04-10
Assignee: Kokusai Denshin Denwa Co., Ltd. (Tokyo, JP)
Primary Class(es): 370/477 704/205
Other Classes:
US Patent Ref:

3786195

Jan, 1974

Shiffman

179/15.

Other Refs: Other References: F. Lee, "Time Compression and Expansion of Speech by Sampling Method,", J. of AES, Nov. 1972, pp. 738-742.