System for carrying out spread spectrum communication through an electric ...

[54] SYSTEM FOR CARRYING OUT SPREAD

SPECTRUM COMMUNICATION THROUGH
AN ELECTRIC POWER LINE

[75] Inventor: Satosbi Hasegawa, Tokyo, Japan

[73] Assignee: NEC Corporation, Tokyo, Japan

[21] Appl. No.: 662,111

[22] Filed: Oct. 18, 1984

[30] Foreign Application Priority Data

Oct. 18, 1983 [JP] Japan 58-194908

Feb. 2, 1984 [JP] Japan 59-17353

Jul. 3, 1984 [JP] Japan 59-137609

[51] Int. CI.* H04B 3/54

[52] U.S. CI 375/1; 340/310 A;

340/825.08

[58] Field of Search 375/1, 111, 113, 115;

340/825.08, 310 R, 538; 455/38, 58; 370/18, 85,

91, 93, 96

[56] References Cited

U.S. PATENT DOCUMENTS

2,435,010 1/1948 Knapp et al 455/58

3,098,215 7/1963 Waite 370/96

3,475,558 10/1969 Cahn 375/1

4,307,380 12/1981 Gander 375/1

4,438,519 3/1984 Bose 375/1

4,468,792 8/1984 Baker et al 375/1

4,517,679 5/1985 Clark et al 375/1

Primary Examiner—Benedict V. Safourek
Attorney, Agent, or Firm—Sughrue, Mion, Zinn,
Macpeak & Seas

[57] ABSTRACT

A communication system for carrying out communication between a plurality of stations through an electric power line operating in a commercial power frequency band. Spread spectrum modulation of an information signal, employing a pseudorandom code sequence is used at a transmitting station. Spread spectrum demodulation is carried out in a receiving station to reproduce the information signal. The modulated signal is spread over a wide frequency band different from the commercial frequency band. Each station may comprise both of a transmitter and a receiver, and may be specified by a an assigned destination address that also is transmitted. The destination station address may be indicated either by an address signal or by an additional pseudorandom code sequence peculiar to a destination station. Alternatively, polling operation is carried out through the electric power line by a polling station to select one of the stations. Preferably, another pseudorandom code sequence is superposed on the modulated signal so as to specify a synchronization signal and different from the pseudorandom code sequences conveying the information signal and/or the destination address.

14 Claims, 28 Drawing Figures