Monitoring system for telecommunication links equipped with repeaters-regenerators

• US 4,334,303 A
• Filed: 04/18/1980
• Issued: 06/08/1982
• Est. Priority Date: 04/19/1979
• Status: Expired due to Term

• Current Assignee: Societe Anonyme de Telecommunications (Safran SA)
• Original Assignee: Societe Anonyme de Telecommunications (Safran SA)
• Inventors: Boutmy, Patrick E., Le Fort, Gilbert J., Bertin, Marcel R., Walraet, Jean G.
• Primary Examiner(s): ORSINO JR, JOSEPH
• Application Number:
  US06/141,679
• Time in Patent Office: 781 Days
• Field of Search: 455/7, 455/9, 455/11, 455/13, 455/15, 455/16, 455/18, 455/601, 179/175.31 R, 375/3, 375/4, 370/13
• US Class Current: 370/243
• CPC Class Codes: H04B 17/40 of relay systems

Abstract

Monitoring system for a forward and backward link equipped with two way repeaters-regenerators comprises a monitoring station including means for transmitting through the forward link information data and a low frequency control signal and for receiving through said backward link information data and supervisory words respectively monitoring the performance of the repeaters-regenerators and identifying errors made therein. In each repeater regenerator a supervisory word is stored in a shift register and advance pulses for said shift register are obtained by frequency division of the low frequency control signal. The supervisory word is completed by a start bit and a stop bit, and modulates the low frequency control signal. The modulated start stop supervisory word is transmitted to the monitoring station through the backward link.

Claims

1. Monitoring system for monitoring a performance factor of two-way repeaters-regenerators of a telecommunication link between a monitoring station and a monitored station, an exemplary performance factor being errors in the repeaters-regenerators,

said telecommunication link including a forward link for transmission of data signals in a first direction between the stations and a backward link for transmission of data signals in a second direction between the stations,

said monitoring station comprising:

sending means for sending information data and a low frequency signal modulated by control pulses through said forward link, and

receiving means for receiving information data from said monitored station and supervisory words indicative of the performance of said repeaters-regenerators, said supervisory words modulating the low frequency signal looped back in said repeaters-regenerators through said backward link;

each of said repeaters-regenerators comprising;

frequency separating means connected to said forward link for separating said control pulses modulating said low frequency signal from said forward information data,

means for detecting said performance of said repeater-regenerator with regard to errors made in an in-line code of said forward and backward information data during each modulating control pulse,

means for detecting the leading edge of said modulating control pulses,

means controlled by said control pulse detecting means for deriving a bit pattern from said detected performances after each detected control pulse,

a shift register

storing said derived bit pattern and a start bit and a stop bit as a supervisory word coupled to said shift register,

frequency dividing means responsive to said modulating control pulses and synchronized by said control pulse detecting means for generating advance pulses of said shift register having a frequency that is a submultiple of said low frequency signal;

means receiving said moulated control pulses for modulating said low frequency signal by the bits of said supervisory word derived from said shift register at said submultiple frequency, and

means connected to said backward link for combining said supervisory word modulating said low frequency signal with said backward information data.

2. The monitoring system of claim 1 wherein each repeater-regenerator comprises

frequency separating means connected to said backward link for separating said supervisory words modulating said low frequency signal and derived from the other repeaters-regenerators on said backward link in response to a same detected control pulse derived from said backward information data, and

means for demodulating said low frequency signal modulated by said supervisory words derived from said other repeaters-regenerators into demodulated supervisory words to be applied to said shift register.

3. A repeater-regenerator for enabling monitoring of a performance factor of a transmission link including:

a monitoring station, a monitored station, plural repeaters-regenerators, a forward link for transmitting signals from the monitoring station to the monitored station via the repeaters-regenerators, and a backward link for transmitting signals from the monitored station to the monitoring station via the repeaters-regenerators, an exemplary performance factor being errors in the transmitted signals susceptible of detection in the repeaters-regenerators, the monitoring station transmitting information data and low frequency signals through said forward link toward the monitored station, the transmitted low frequency signal being modulated with control pulses, the monitored station responding to the signal of the forward link and transmitting the low frequency modulated signal and an information signal toward the monitoring station via the backward link, each repeater-regenerator comprising a first channel responsive to and amplifying the information data signal transmitted in the forward link toward the monitored station, a second channel responsive to the low frequency, modulated signal transmitted toward the monitored station in the forward link, a third channel responsive to and amplifying the information data signal transmitted in the backward link toward the monitoring station, a fourth channel responsive to the low frequency modulated signal transmitted in the backward link toward the monitoring station, said second channel including;

means for demodulating the transmitted low frequency modulated signal in the second channel to derive first, second and third control pulses in response to a control pulse derived at the monitoring station, means activated by the first control pulse to be responsive to the signal in the first and third channels for deriving a multi-bit binary signal having a value indicative of the performance factor of the forward and backward links, a multistage shift register for storing a supervisory word having multiple intermediate bits as well as first and last binary bits having values associated with stop and start values and activated by a second control pulse replica so intermediate stages thereof are loaded in response to the multi-bit performance factor indicating binary signal and first and last stages thereof are respectively loaded with binary bit values associated with start and stop values for a multi-bit binary word, means activated by the third control pulse to be responsive to the transmitted low frequency signal for deriving a shift signal having transitions synchronized with and at lower frequency than the frequency of the transmitted low frequency signal, the shift signal being applied to a shift input of the shift register so that the shift register derives a sequence of pulses having binary levels indicative of the binary bit values loaded into the first, intermediate and last stages of the shift register, modulator means responsive to the transmitted low frequency signal in the second channel and the sequence of pulses for deriving another modulated signal wherein the low frequency is modulated by the sequence of pulses;

means for coupling the amplified information signal in the first channel and the low frequency modulated signal in the second channel to the forward link toward the monitored station;

the fourth channel including means for demodulating the low frequency signal transmitted in the backward link toward the monitoring station to derive a replica of the supervisory words and performance factor indicating words derived from other repeaters-regenerators which transmit toward said one repeater-generator via the backward loop, the replica of the supervisory words and performance indicating words derived from other repeater-regenerators being applied to the last stage of the shift register to be shifted through the shift register in response to the shift signal, whereby the shift register supplies the bits in the supervisory words and performance indicating words derived from other repeater-regenerators in sequence to the modulator which responds to the said bits in deriving the another modulated signal and means for coupling the amplified information signal in the third channel and the another modulated signal to the backward link toward the monitoring station.

4. A repeater-regenerator in a transmission link including:

a monitoring station, a monitored station, N of the repeater-regenerator circuits, where N is an integer greater than one, a forward link for transmitting signals from the monitoring station to the monitored station via the N repeater-regenerator circuits, and a backward link for transmitting signals from the monitored station to the monitoring station via the N repeaters-regenerator circuits, an exemplary performance factor being errors in the transmitted signals susceptible of detection in the repeater-regenerator circuits, the monitoring station transmitting information data and low frequency signals through said forward link toward the monitored station, the transmitted low frequency signal being modulated with control pulses, the monitored station responding to the signal of the forward link and transmitting the low frequency modulated signal and another information signal toward the monitoring station via the backward link, repeater-regenerator k comprising means for amplifying the information data signal transmitted in the forward link toward the monitored station, means for demodulating the transmitted low frequency modulated signal to derive a control signal, means activated by the control signal to be responsive to the information signal transmitted via the forward link for deriving a multi-bit supervisory binary signal word having start and stop bits and intermediate bits with values indicative of the performance factors of the forward link, a multistage shift register activated by the control signal so intermediate stages thereof are loaded in response to the multi-bit supervisory binary signal word and first and last stages thereof are respectively loaded with binary bit values associated with start and stop values for the multi-bit supervisory binary word, means activated by the control signal to be responsive to the transmitted low frequency signal for deriving a shift signal having transitions synchronized with and at lower frequency than the frequency of the transmitted low frequency signal, the shift signal being applied to a shift input of the shift register so that the shift register derives a sequence of pulses having binary levels indicative of the binary bit values loaded into the first, intermediate and last stages of the shift register, modulator means responsive to the transmitted low frequency signal in the forward link and the sequence of pulses for deriving another modulated signal wherein the low frequency is modulated by the sequence of pulses, and means for coupling the amplified information signal in the forward link and the low frequency signal in the forward link toward the monitored station;

means for amplifying the information data signal transmitted in the backward link toward the monitoring station, means responsive to the low frequency modulated signal transmitted in the backward link toward the monitoring station for demodulating the low frequency signal transmitted in the backward link toward the monitoring station to derive a replica of multi-bit supervisory signals derived from shift registers at repeater-regenerator circuits (k+1), (k+2)-(N-1), N, the replica of the signals derived from the registers at circuits of circuits (k+1), (k+2)-(N-1), N being applied to the last stage of the shift register of circuit k to be shifted through the shift register in response to the shift signal whereby the shift register supplies the bits in the supervisory words derived from the circuits k, (k+1), (k+2)-(N-1), N in the stated sequence to the modulator, and means for coupling the amplified information signal in the backward link and the another modulated signal toward the monitoring station.

5. Apparatus for monitoring a performance factor of a transmission link including:

a monitoring station, a monitored station, N repeater-regenerator circuits, where N is an integer greater than one, a forward link for transmitting signals from the monitoring station to the monitored station via the N repeater-regenerator circuits, and a backward link for transmitting signals from the monitored station to the monitoring station via the N repeater-regenerator circuits, an exemplary performance factor being errors in the transmitted signals susceptible of detection in the repeater-regenerator circuits, the monitoring station comprising;

means for transmitting information data and low frequency signals through said forward link toward the monitored station, means for modulating the transmitted low frequency signal with control pulses;

the k repeater-regenerator circuit including (where k is selectively every integer from 1 to N);

means for amplifying the information data signal transmitted in the forward link toward the monitored station, means for demodulating the transmitted low frequency modulated signal to derive a control signal, means activated by the control signal to be responsive to the information signal transmitted via the forward link for deriving a multi-bit supervisory binary signal word having start and stop bits and intermediate bits with values indicative of the performance factor of the forward link, a multistage shift register activated by the control signal so intermediate stages thereof are loaded in response to the multi-bit supervisory binary signal word and first and last stages thereof are respectively loaded with binary bit values associated with start and stop values for the multi-bit supervisory binary word, means activated by the control signal to be responsive to the transmited low frequency signal for deriving a shift signal having transitions synchronized with and at lower frequency than the frequency of the transmitted low frequency signal, the shift signal being applied to a shift input of the shift register so that the shift register derives a sequence of pulses having binary levels indicative of the binary bit values loaded into the first, intermediate and last stages of the shift register, modulator means responsive to the transmitted low frequency signal in the forward link and the sequence of pulses for deriving another modulated signal wherein the low frequency is modulated by the sequence of pulses and means for coupling the amplified information signal in the forward link and the low frequency signal in the forward link toward the monitored station;

the monitored station comprising;

means responsive to the signal of the forward link, and means for transmitting the low frequency modulated signal and another information signal toward the monitoring station via the backward link;

the k repeater-regenerator circuit further including;

means for amplifying the information data signal transmitted in the backward link toward the monitoring station, means responsive to the low frequency modulated signal transmitted in the backward link toward the monitoring station for demodulating the low frequency signal transmitted in the backward link toward the monitoring station to derive a replica of multi-bit supervisory signals derived from shift registers at repeater-regenerator circuits (k+1), (k+2)-(N-1), N, the replica of the signals derived from the registers at circuits (k+1), (k+2)-(N-1), N being applied to the last stage of the shift register of circuit k to be shifted through the shift register in response to the shift signal whereby the shift register supplies the bits in the supervisory words derived from the circuits k, (k+1), (k+2)-(N-1), N in the stated sequence to the demodulator, and means for coupling the amplified information signal in the backward link and the another modulated signal toward the monitoring station;

the monitoring station further comprising;

means responsive to the information signal transmitted toward it via the backward link, and means responsive to the modulated signal transmitted toward it via the backward link for detecting the performance factor indicating bits of the particular and other circuits.

6. Apparatus for monitoring a performance factor of a transmission link including:

a monitoring station, a monitored station, plural repeater-regenerator circuits, a forward link for transmitting signals from the monitoring station to the monitored station via the repeater-regenerator circuits, and a backward link for transmitting signals from the monitored station to the monitoring station via the repeater-regenerator circuits, an exemplary performance factor being errors in the transmitted signals susceptible of detection in the repeater-regenerator circuits, the monitoring station comprising;

means for transmitting information data and low frequency signals through said forward link toward the monitored station, means for modulating the transmitted low frequency signal with control pulses;

each repeater-regenerator circuit including;

a first channel responsive to and amplifying the information data signal transmitted in the forward link toward the monitored station, a second channel responsive to the transmitted low frequency, modulated signal;

said second channel including;

means for demodulating the transmitted low frequency modulated signal in the second channel to derive first, second and third control pulses in response to each control pulse derived at the monitoring station, means activated by the first control pulse to be responsive to the signal in the first channel for deriving a multi-bit supervisory binary signal word having start and stop bits and intermediate bits with values indicative of the performance factor of the forward link, a multistage shift register activated by the second control pulse so intermediate stages thereof are loaded in response to the multi-bit supervisory binary signal word and first and last stages thereof are respectively loaded with binary bit values associated with start and stop values for the multi-bit supervisory binary word, means activated by the third control pulse to be responsive to the transmitted low frequency signal for deriving a shift signal having transitions synchronized with and at lower frequency than the frequency of the transmitted low frequency signal, the shift signal being applied to a shift input of the shift register so that the shift register derives a sequence of pulses having binary levels indicative of the binary bit values loaded into the first, intermediate and last stages of the shift register, modulator means responsive to the transmitted low frequency signal in the second channel and the sequence of pulses for deriving another modulated signal wherein the low frequency is modulated by the sequence of pulses;

each repeater-regenerator circuit coupling the amplified information signal in the first channel and the low frequency signal in the second channel to the forward link toward the monitored station;

the monitored station responding to the signal of the forward link and transmitting the low frequency modulated signal and another information signal toward the monitoring station via the backward link;

each repeater-regenerator circuit further including;

a third channel responsive to and amplifying the information data signal transmitted in the backward link toward the monitoring station, a fourth channel responsive to the low frequency modulated signal transmitted in the backward link toward the monitoring station, the fourth channel including means for demodulating the low frequency signal transmitted in the backward link toward the monitoring station to derive a replica of multi-bit supervisory signals derived from shift registers at the repeater-regenerator circuits in the backward link between the particular repeater-regenerator circuit and the monitored station, the replica of the signals derived from the registers at the other circuits being applied to the last stage of the shift register to be shifted through the shift register in response to the shift signal whereby the shift register supplies the bits in the supervisory words derived from the particular circuit and the other circuit in sequence to the modulator, the repeater-regenerator circuit including means for coupling the amplified information signal in the third channel and the another modulated signal to the backward link toward the monitoring station;

the monitoring station further including;

means responsive to the information signal transmitted toward it via the backward link, and means responsive to the modulated signal transmitted toward it via the backward link for detecting the performance factor indicating bits of the particular and other circuits.

7. A repeater-regenerator in a transmission link including:

a monitoring station, a monitored station, N of the repeater-regenerator circuits where N is an integer greater than one, a forward link for transmitting signals from the monitoring station to the monitored station via the N repeaters-regenerator circuits, and a backward link for transmitting signals from the monitored station to the monitoring station via the N repeaters-regenerator circuits, an exemplary performance factor being errors in the transmitted signals susceptible of detection in the repeater-regenerator circuits, the monitoring station transmitting information data and low frequency signals through said forward link toward the monitored station, the transmitted low frequency signal being modulated with control pulses;

the monitored station responding to the signals of the forward link and transmitting the low frequency modulated signal and another information signal toward the monitoring station via the backward link;

repeater-regenerator k comprising means for handling the information signals transmitted via the forward and backward links, means for coupling the handled information signal transmitted via the forward link and the low frequency signal transmitted via the forward link to repeater-regenerator (k+1), means responsive to at least one of the handled information signals for deriving a multi-bit supervisory word signal having start and stop bits and intermediate bits with values indicative of the performance factor of at least one of the links as detected at repeater-regenerator k, a multistage shift register having intermediate stages responsive to the intermediate bits and first and last stages responsive to predetermined bit values for start and stop bits, means responsive to the low frequency signal for shifting the contents of the shift register so there is derived from the shift register last stage a sequence of pulses, means for modulating the sequence of pulses to derive another low frequency information signal, means for coupling the handled information signal transmitted via the backward link and the another low frequency information signal to repeater-regenerator (k-1), means for coupling the another low frequency information signal from repeater-regenerators (k+1), (k+2)-(N-1), N to the first stage of the shift register so the start and stop bits and intermediate bits of supervisory signals from repeater-regenerators k, (k+1), (k+2)-(N+1), N are derived from the shift registerlast stage and coupled to repeater-regenerators (k-1), (k-2)-1.