RADIO-FREQUENCY RELAY SYSTEM

• US 3,866,121 A
• Filed: 11/21/1972
• Issued: 02/11/1975
• Est. Priority Date: 11/24/1971
• Status: Expired due to Term

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Kazuo Morita, Masami Takada, Shinichi Nakamura
• Inventors: Nakamura, Shinichi, Morita, Kazuo, Takada, Masami
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US05/308,621
• Time in Patent Office: 812 Days
• Field of Search: 325/2,3,56,303,304 340/147SC,147C 333/2,3 178/69G 179/17R,17A
• US Class Current: 455/10
• CPC Class Codes: H04B 1/74 for increasing reliability, e.g. using redundant or spare channels or apparatus replacing by standby devices for amplifiers H03F1/52, H03F1/542

Abstract

A radio frequency relay system including at least two regular and independent transmission paths and a spare transmission path zigzagging between repeater stations in the regular independent transmission paths. The spare path provides an alternate route for signals of any of said regular paths when sections of the regular paths have high signal degradation qualities, such as rain or fog for high frequency signals. At various repeater stations of each regular path a common repeater is used which is capable of receiving and transmitting signals in either the regular path or the spare path.

Claims

1. A radio frequency relay system for use in the frequency range above 10 GHz, comprising:

a first radio signal transmission path comprising a first plurality of consecutively positioned relay stations, each of said first plurality of relay stations comprising receiving means adapted to receive a radio frequency signal in said first radio signal transmission path, transmitter means for transmitting a radio frequency signal along said first radio signal transmission path, and means connecting said receiving means and said transmitting means for causing said transmitting means to transmit said received radio frequency signal, a second radio signal transmission path, located over one kilometer away from said first radio signal transmission path, comprising a second plurality of relay stations, each of said second plurality of relay stations comprising receiving means adapted to receive a radio frequency signal in said second radio signal transmission path, transmitter means for transmitting a radio frequency signal along said second radio signal transmission path, and means connecting said receiving means and said transmitting means for causing said transmitting means to transmit said received radio frequency signal, and a spare radio frequency transmission path formed at an angle with respect to and intersecting said first and second radio frequency transmission paths, said spare transmission path comprising at least two of said first plurality of relay stations (first and third relay stations) and one of said second plurality of relay stations (second relay station), wherein, said first relay station comprises auxiliary transmitter means adapted to transmit a radio frequency signal along said spare path towards said second relay station, and switch means for selectively connecting said relay station receiver means to said auxiliary transmitter means to cause the signal received along said first path by said receiver means to be transmitted along said spare path by said auxiliary transmitter means, said second relay station comprises auxiliary receiver means adapted to receive a radio frequency signal emanating from the auxiliary transmitter of said first relay station, auxiliary transmitter means adapted to transmit a radio frequency signal along said spare path towards said third relay station, and switch means for selectively connecting together said auxiliary receiving and transmitting means of said second relay station for causing a radio signal received by said auxiliary receiving means to be transmitted by said auxiliary transmitting means, and said third relay station comprising auxiliary receiving means adapted to receive a radio frequency signal emanating from the auxiliary transmitter of said second relay station, and switch means for selectively connecting said auxiliary receiving means to said relay station transmitting means to cause the signal received along said spare path by said auxiliary receiver means to be transmitted along said first path by said transmitter means.

2. A radio frequency relay system as claimed in claim 1 wherein each of said relay stations forming a part of said spare path and one of said first and second paths comprises, in addition to said receiving means and transmitting means, an auxiliary receiving means and an auxiliary transmitting means adapted for receiving and transmitting radio frequency signals along said spare path, first normally closed switch means connecting said receiving means to said transmitting means, secondly normally closed switch means connecting said auxiliary receiving means to said auxiliary transmitting means, first normally open switch means connected between said auxiliary receiving means and said transmitting means, second normally open switch connected between said receiving means and said auxiliary transmitting means, whereby attenuation in between two consecutive repeating stations in either said first or second paths can be avoided by opening said normally closed switches, and closing at least one of said normally open switches in each said two relay stations.