Patent EP0368282A2 successfully refreshed from Google Patents.
EP0368282A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A bidirectional optical transmission system having a light-interruption detecting function
Assignee: Fujitsu Ltd
•
Filing: 1989-11-08
•
Granted: —
•
Expires: 2009-11-08
Abstract
Abstract Disclosed is a bidirectional optical transmission system for effecting bidirectional optical transmission between offices by utilizing a common optical transmission line (30). Each office (10;20) comprises: a light transmitting unit (160;260) for transmitting a light signal to another office (20;10); a light receiving unit (170;270) for receiving a signal from the other office (20;10); and a light passing unit (130; 230) for passing the transmission signal from the light transmitting unit (160; 260) to the optical transmission line (30) and for passing the receiving signal from the optical transmission line (30) to the light receiving unit (170;270). To discriminate whether the received signal is the signal from the other office (20;10) or from the same office (10; 20) by crosstalk through the light passing unit (130;230), the light transmitting unit (160; 260) comprises a light-interruption detecting signal superimposing unit (162;262) for superimposing a light-interruption detecting signal on the transmission signal, the frequencies of the light-interruption detecting signals from the first office (10; 20) and from the other office (20;10) being different from each other; and the light receiving unit (170; 270) comprises a light-interruption detecting signal detecting unit (172;272) for detecting the light-interruption detecting signal from the other office (20;10) by identifying the frequency of the light-interruption detecting signal from the other office (20;10).
Inventors
- 👤 Kazuyoshi Lm Yoshinocho Minami 503 Shimizu
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 23:20
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/07; H04B10/075; H04B10/077; H04B10/25; H04B10/2589; H04B2210/00; H04B2210/07; H04B2210/075
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
221 words
A bidirectional optical transmission system having a light-interruption detecting function, said bidirectional optical transmission system effecting bidirectional optical transmission between offices through an upward channel and a downward channel by utilizing a common optical transmission line (30), each of said offices comprising: light transmitting means (160 or 260) for generating a transmission signal having a high level and a low level to be transmitted from a first office through said upward channel of said common optical transmission line to another office; light receiving means (170 or 270) for receiving a receiving signal from said other office through said downward channel to said first office; and light passing means (130 or 230) for passing said transmission signal from said light transmitting means to said upward channel and for passing said receiving signal from said downward channel to said light receiving means; said light transmitting means comprising light-interruption detecting signal superimposing means (162 or 262) for superimposing a light-interruption detecting signal on said transmission signal, the frequencies of the light-interruption detecting signals from said first office and from said other office being different from each other; and said light receiving means comprising light-interruption detecting signal detecting means (172 or 272) for detecting said light-interruption detecting signal from said other office by identifying said frequency of the light-interruption detecting signal from said other office.
Claim 2
Dependent Claim
221 words
A bidirectional optical transmission system having a light-interruption detecting function, said bidirectional optical transmission system effecting bidirectional optical transmission between offices through an upward channel and a downward channel by utilizing a common optical transmission line (30), each of said offices comprising: light transmitting means (160 or 260) for generating a transmission signal having a high level and a low level to be transmitted from a first office through said upward channel of said common optical transmission line to another office; light receiving means (170 or 270) for receiving a receiving signal from said other office through said downward channel to said first office; and light passing means (130 or 230) for passing said transmission signal from said light transmitting means to said upward channel and for passing said receiving signal from said downward channel to said light receiving means; said light transmitting means comprising light-interruption detecting signal superimposing means (162 or 262) for superimposing a light-interruption detecting signal on said transmission signal, the frequencies of the light-interruption detecting signals from said first office and from said other office being different from each other; and said light receiving means comprising light-interruption detecting signal detecting means (172 or 272) for detecting said light-interruption detecting signal from said other office by identifying said frequency of the light-interruption detecting signal from said other office.
Claim 3
Dependent Claim
27 words
A bidirectional optical transmission system having light-interruption detecting function as claimed in claim 1, wherein said signal passing means (130 or 230) is a light directional coupler.
Claim 4
Dependent Claim
38 words
A bidirectional optical transmission system having light-interruption detecting function as claimed in claim 1, wherein said bidirectional optical transmission system is a wavelength multiplexing system and said signal passing means (130 or 230) is a wavelength multiplexing module.
Claim 5
Dependent Claim
71 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 1, wherein said light transmitting means (160 or 260) comprises: light amplifying means (161 or 261) for amplifying a signal to be transmitted; and light-interruption detecting signal generating means (162 or 262) for generating said light-interruption detecting signal; said light-interruption detecting signal being superimposed, by said light-interruption detecting signal superimposing means, on the signal to be transmitted.
Claim 6
Dependent Claim
88 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 4, wherein said light amplifying means (161 or 261) comprises: signal amplifying means (402) for amplifying a signal to be transmitted; light-interruption detecting signal amplifying means (404) for amplifying said light-interruption detecting signal; signal synthesizing means for synthesizing the amplified signal and the amplified light-interruption detecting signal; and electrical-optical converting means (401) for converting the synthesized signal into an optical signal; said optical signal being sent to said light passing means (130 or 230).
Claim 7
Dependent Claim
46 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 5, wherein said light amplifying means (161 or 261) further comprises clamping means (406) for clamping the lowest level of said light-interruption detecting signal to the low level of said transmission signal.
Claim 8
Dependent Claim
96 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 6, wherein said signal amplifying means (402) is a first NPN transistor having its base connected to receive said signal to be transmitted; said light-interruption detecting signal amplifying means (404) is a second NPN transistor having its base connected to receive said light-interruption detecting signal and having its emitter connected through an emitter bias resistor (50) to a negative terminal of a power supply; the collectors of said first and second NPN transistors being commonly connected to said electrical-optical converting means (401).
Claim 9
Dependent Claim
86 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 7, wherein said clamping means (406) comprises a clamping diode (54) having its cathode connected to the emitter of said second NPN transistor (404) and having its anode connected to a point of a fixed potential, whereby when the potential at the emitter of said second NPN transistor becomes lower than a predetermined value, said clamping diode is forward biased to raise the potential of the emitter of said second NPN transistor.
Claim 10
Dependent Claim
89 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 8, wherein said clamping means (406) further comprises an operational amplifier (53) having a non-inverting input for applying a reference voltage, an inverting input connected through a first resistor (55) to said anode of said clamping diode (54), and an output connected through a second resistor (57 and 52) to the base of said second NPN transistor (404), the inverting input and the output of said operational amplifier being connected through a third resistor (56).
Claim 11
Dependent Claim
26 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 9, wherein said electrical-optical converting means (401) is a light emitting diode.
Claim 12
Dependent Claim
25 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 9, wherein said electrical-optical converting means (401) is a laser diode.
Claim 13
Dependent Claim
84 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 4, wherein said light amplifying means (161 or 261) comprises: signal synthesizing means (501) for synthesizing said signal to be transmitted and said light-interruption detecting signal; signal amplifying means (502) for amplifying the synthesized signal output from said signal synthesizing means (501); and electrical-optical converting means (503) for converting the amplified synthesized signal into an optical signal; said optical signal being sent to said light passing means (130 or 230).
Claim 14
Dependent Claim
39 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 12, further comprising a clamping means (406) for clamping the lowest level of said light-interruption detecting signal to the low level of said transmission signal.
Claim 15
Dependent Claim
38 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 13, wherein said signal amplifying means (502) is an NPN transistor having its base connected to the output of said signal synthesizing means (501).
Claim 16
Dependent Claim
83 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 14, wherein said clamping means (406) comprises a clamping diode (54) having its cathode connected to the emitter of said NPN transistor (502) and having its anode connected to a point of a fixed potential, whereby when the potential at the emitter of said NPN transistor becomes lower than a predetermined value, said clamping diode is forward biased to raise the potential of the emitter of said NPN transistor.
Claim 17
Dependent Claim
88 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 15, wherein said clamping means (406) further comprises an operational amplifier (53) having a non-inverting input for applying a reference voltage, an inverting input connected through a first resistor (55) to said anode of said clamping diode (54), and an output connected through a second resistor (57 and 52) to the base of said NPN transistor (502), the inverting input and the output of said operational amplifier being connected through a third resistor (56).
Claim 18
Dependent Claim
26 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 16, wherein said electrical-optical converting means (401) is a light emitting diode.
Claim 19
Dependent Claim
25 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 16, wherein said electrical-optical converting means (401) is a laser diode.
Claim 20
Dependent Claim
94 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 1, wherein said light receiving means (170 or 270) further comprising a light receiving circuit (171 or 271) having a photo diode (601) for converting an optical signal transmitted through said common optical transmission line (30) into an electric signal, an amplifier (601 and 602) for amplifying said electrical signal output from said photo diode (601), and a discriminating circuit (604) for discriminating the high level and the low level of the signal output from said amplifier (602 and 603).
Claim 21
Dependent Claim
85 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 19, wherein said light-interruption detection signal detecting means (171 or 172) comprises: a band-pass filter (605) for passing only the signal having the frequency of said light-interruption detecting signal from said another office; a preamplifier (606) for amplifying the signal passed through said band-pass filter; and a discriminating circuit (607) for discriminating whether or not the signal output from said preamplifier (606) includes said light-interruption detecting signal from said other office.
Claim 22
Dependent Claim
32 words
A bidirectional optical transmission system having a light-interruption detecting function as claimed in claim 1, wherein said frequencies of said light-interruption detecting signals are higher than the frequency of said transmission signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.