Title:
SQUELCH METHOD IN NON-REGENERATIVE RELAY STATION
Document Type and Number:
Japanese Patent JP3210930
Kind Code:
B2
Abstract:
PURPOSE: To facilitate the maintenance and monitor of a subordinate station due to raising of an alarm in the operation of a squelch circuit by giving effect of alarm transmission and transmission level reduction up to a subordinate non-regenerative relay station due to transmission level reduction and alarm transmission following reception level reduction in at least one of non- regenerative relay stations.
CONSTITUTION: When a reception input of one system of a non-regenerative relay digital radio station 206 is decreased by a flat fade margin or over and a squelch detector 28 detects the reception level reduction, an alarm is raised by cutting off a final stage amplifier of an automatic gain controlled amplifier 27 of one system of the non-regenerative relay digital radio station 206 and an output signal of an intermediate frequency band processing section 102 is lost. Thus, one output signal of transmitters 20, 21 and an output signal sent from a transmission antenna 6 to a non-regenerative relay digital radio station 207 are lost. Thus, the alarm raised by reception level reduction continues in next and succeeding radio stations.
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Inventors:
Kazuji Watanabe
Osamu Kagami
Osamu Kagami
Application Number:
JP7736893A
Publication Date:
September 25, 2001
Filing Date:
March 12, 1993
Export Citation:
Assignee:
Nippon Telegraph and Telephone Corporation
International Classes:
H04B1/52; H04B7/15; H04B17/40; (IPC1-7): H04B7/15; H04B1/52; H04B17/02
Domestic Patent References:
| JP3268624A | ||||
| JP4109719A | ||||
| JP3266531A |
Attorney, Agent or Firm:
Keiichi Yamamoto