JPH0326039A - Optical communication equipment - Google Patents

Abstract

PURPOSE:To eliminate the need for the setting of inversion and noninversion of a retransmission signal and a reception signal at each reception station by integrating an NRZI coding and decoding circuit. CONSTITUTION:A transmission original signal (a) is outputted from the transmission section 4 of a transmission station 1 to a coding circuit 5, where the signal is subjected to NRZI coding into a signal (b), the signal is converted into an optical signal at an optical transmitter 6 and send to the optical receiver 8 of a reception station 2 via an optical cable 7. Then the output signal (c) from the optical receiver 8 is subjected to NRZI conversion into a signal (d) by a decoding circuit 9 and the signal (d) is inputted to a reception section 10 as a signal equivalent to the transmission original signal (a). Moreover, the signal (c) is inverted into a signal (e) at an inverting circuit 11, converted into an optical signal by an optical transmitter 12 and sent to the optical receiver 14 of the reception station 3 via an optical cable 13. Thus, the setting of inversion and non-inversion of the retransmission signal and the reception signal is not required for each reception station.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a baseband inversion/retransmission optical communication system. In particular, the present invention relates to a means for making it unnecessary to set inversion and non-inversion for each receiving station.

〔overview〕

The present invention makes it possible to eliminate the need for setting retransmission signals and reception signals to be inverted or non-inverted at each receiving station by incorporating an NRZI encoding and decoding circuit in a baseband inversion regeneration optical communication means. This is how it was done.

[Conventional technology]

Optical communication devices that perform baseband relay and retransmission employ inverted retransmission, which can easily suppress signal jitter. However, in the conventional example, as shown in FIG. Switches 20 and 2 for switching
2 must be switched for each receiving station, making the setting complicated. Therefore, the retransmission signal is inverted for every plural receiving stations within the permissible range of jitter of the received signal. ) and switch 20
and 22 (if the received signal is an inverted signal, the received signal is inverted and converted into a non-inverted signal by the receiving unit IO and 16
A switch is made between inputting the received signal manually to the receivers 10 and 16, or inputting the received signal to the receivers 10 and 16 without inverting it if the received signal is a non-inverted signal. ) settings are required.

[Problem that the invention seeks to solve]

In such a conventional example, it is necessary to set whether the retransmission signal and the received signal are inverted or non-inverted for each receiving station, and the setting is complicated.

The present invention aims to eliminate such drawbacks, and aims to provide an optical communication device having means that eliminates the need for settings at each receiving station.

[Means for solving problems]

The present invention provides a transmitting station that includes a transmitter that generates a baseband electrical signal, a first optical transmitter that converts the electrical signal into an optical signal and sends it out, and an optical receiver that converts the incoming optical signal into an electrical signal. a receiving section that receives an electrical signal related to the electrical signal converted by this optical receiver, and converts the electrical signal related to the electrical signal converted by this optical receiver into an optical signal and relays it to the next receiving station. In the optical communication device, the transmitting station transmits the baseband electric signal generated by the transmitter to an NRZ I
The receiving station includes a coding circuit that converts the code and provides the signal to the first optical transmitter, and the receiving station includes a decoding circuit that converts the electrical signal converted by the optical receiver to NRZI decoding and provides the signal to the receiving section, and The present invention is characterized in that it includes an inversion circuit that inverts the polarity of the electrical signal converted by the receiver and supplies it to the second optical transmitter.

[Effect]

The transmitting station generates a transmitting signal and transmits this transmitting signal to the NRZ
The I-encoded electrical signal is converted into an optical signal and transmitted.

At the receiving station, the received signal converted from the optical signal to an electrical signal is
RZ I decoding and receiving this decoded received signal,
On the other hand, a signal obtained by inverting the received signal is transmitted as an optical signal.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the structure of this embodiment.

In this embodiment, as shown in FIG. The receiving stations 2 and 3 are composed of optical receivers 8 and 14, decoding circuits 9 and 15, receiving sections 10 and 16, and an inverting circuit 1.
1 and 17, and optical transmitters 12 and 18, and optical cables 7 and 13 are used between the transmitting station 1 and the receiving station 2, between the receiving station 2 and the receiving station 3, and between the subsequent receiving stations. and 19. That is, this embodiment includes a transmitting station 1 equipped with a transmitting section 4 that generates a baseband electrical signal, an optical transmitter 6 that converts this electrical signal into an optical signal and sends it out, and a transmitting station 1 that converts an incoming optical signal into an electrical signal. Optical receiver 8 to convert
(14), a receiving section 10 (16) that receives an electrical signal related to the electrical signal converted by this optical receiver 8 (14).
) and a receiving station 2 (3) equipped with an optical transmitter 12 (18) that converts the electrical signal related to the electrical signal converted by this optical receiver into an optical signal and relays it to the next receiving station. Furthermore, as a characteristic feature of the present invention, the transmitting station l includes an encoding circuit 5 that converts the paceband electrical signal generated by the transmitter into an NRZ I code and supplies it to the first optical transmitter, The receiving station 2 (3) has an optical receiver 8 (1
A decoding circuit 9 (15) performs NRZ I decoding on the electrical signal converted in step 4) and supplies it to the receiving section, and an optical transmitter 12 (18) inverts the polarity of the electrical signal converted by the optical receiver. ).

Next, the operation of this embodiment will be explained. FIG. 2 is an example of a time chart of signals indicated by symbols a to h in FIG.

However, in this time chart, delays in the encoder circuit 5 and optical cables 7, l3 and 19 are ignored, and delays in the optical transmitters 6, l2 and 18 and optical receivers 8 and 14 are ignored.
The delay caused by this is defined as time T at the rising edge of the signal and 0 at the falling edge of the signal.

First, the operation at transmitting station l will be explained.

The original transmission signal a is output from the transmitting unit 4 of the transmitting station 1, NRZI-encoded into a signal B by the encoding circuit 5, converted to an optical signal by the optical transmitter 6, and sent to the receiving station 2 via the optical cable 7. The signal is sent to the optical receiver 8.

Next, the operation at the receiving station 2 will be explained.

The rising portion of the output signal C from the optical receiver 8 becomes a signal delayed by a time Td from the signal b within the transmitting station 1. Signal C
is NRZ-converted into a signal d in the decoding circuit 9. signal d
is manually input to the receiving section 10 as a signal equivalent to the original transmission signal a, although it includes the jitter of the maximum time Ta. Further, the signal C is inverted into a signal e by an inverting circuit l1, converted into an optical signal by an optical transmitter 12, and sent to the optical receiver 14 of the receiving station 3 via an optical cable l3.

Next, the operation of the receiving station 3 will be explained.

The output signal f from the optical receiver 14 is a signal whose rising part is delayed by a time Td compared to the signal e in the receiving station 2, that is, the signal is delayed by the entire time T from the signal b in the transmitting station 1, resulting in signal distortion. The rate is almost O.

The signal f is NRZI-converted into a signal g by the decoding circuit 15. Although the signal g has an overall delay of time T compared to the original transmission signal a, it is regenerated into a signal with a distortion factor of almost "0" and input to the receiving section 16. Moreover, the signal f is the inverting circuit 1
At step 7, the signal h is inverted, converted into an optical signal by an optical transmitter 18, and sent to the next receiving station via an optical cable 19.

As explained above, the original transmission signal is regenerated into a signal including jedder of time Td or less without setting retransmission signals and inversion and non-inversion of the received signal at all connected receiving stations. [Effects of the Invention] As explained above, the present invention has the effect that by incorporating the NRZI encoding and decoding circuit, it is possible to eliminate the need for setting retransmission signals and reception signals to be inverted or non-inverted at each receiving station. There is.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of an embodiment of the present invention. FIG. 2 is a time chart showing the operation of the embodiment of the present invention. FIG. 3 is a block diagram showing the structure of a conventional example. DESCRIPTION OF SYMBOLS 1... Transmitting station, 2, 3... Receiving station, 4... Transmitting section, 5... Encoding circuit, 6, 12, 18... Optical transmitter, 7, ■3, 19. ...Optical cable, 8, 14... Optical receiver, 9, 15... Decoding circuit, 10, l6...
Receiving section, 11, 17... Inversion circuit, 20, 21, 22
, 23... switch.

Claims (1)

[Claims] 1. A transmitting station equipped with a transmitter that generates a baseband electrical signal and a first optical transmitter that converts the electrical signal into an optical signal and sends it out; an optical receiver for converting, a receiving section that receives an electrical signal related to the electrical signal converted by this optical receiver, and a receiving unit that converts the electrical signal related to the electrical signal converted by this optical receiver into an optical signal for the next stage. In the optical communication device, the transmitting station converts the baseband electrical signal generated by the transmitting unit into an NRZI code, and converts the baseband electric signal generated by the transmitting unit into the first optical signal. The receiving station is equipped with an encoding circuit that supplies the signal to the transmitter, and the receiving station converts the electrical signal converted by the optical receiver into N
Optical communication comprising: a decoding circuit that performs RZI decoding and conversion and provides the signal to the receiver; and an inversion circuit that inverts the polarity of the electrical signal converted by the optical receiver and provides the signal to the second optical transmitter. Device.