JPH0530038A - Optical digital transmitter - Google Patents

Abstract

PURPOSE:To adjust the optical transmission level so that the optical reception level is not at the outside of a demodulation enable range. CONSTITUTION:An optical reception section feedback circuit output 9 is given to a converter, in which A/D-conversion is implemented and an A/D conversion output 14 is outputted. The output 14 is sent while being multiplexed onto the transmission direction bit string 8. Moreover, opposite station optical input level information 15 is extracted from a reception direction pulse train extractor output 5 by using an extractor 37. The output 15 is given to a converter 38, in which the signal is D/A-converted and its output 16 varies the AC and DC gain of the transmission circuit and Dc amplifier circuit thereby circuit the transmission optical level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission device, and more particularly to an optical digital transmission device.

[0002]

2. Description of the Related Art A conventional optical digital transmission apparatus, as shown in FIG. 2, is a converter 21 for converting an optical signal 1 into an electric signal 3.
Then, the signal obtained by superimposing the electric signal 3 and the electric signal output 9 of the feedback circuit is amplified, and the electric signal 4 is output. Amplifier 22
A feedback circuit 23 for returning the electric signal 4 to the amplifier 22; an extractor 24 for inputting the electric signal 4 to extract the clock component 13; and an extractor for outputting the electric signal 5 from the electric signal 4 in synchronization with the clock component 13. An amplifier 26 which has a receiving unit composed of a device 25 and which receives an electric signal 6 and outputs an electric signal 7 and an electric signal 1 for amplifying a DC electric signal 12
An amplifier 27 that outputs 0, an electric signal 7 and an electric signal 10
It has a transmitter composed of a converter 28 for converting the signal superposed with and into the optical signals 2 and 11 and a detector 29 for converting the optical signal 11 into the DC electric signal 12.

[0003]

In this conventional optical digital transmission device, the optical transmission output is automatically adjusted so that it is always constant, and the optical receiving side is adapted to the level fluctuation of the optical signal on the transmission line. The system follows only in. for that reason,
If the level fluctuation of the optical signal is out of the tracking range on the optical receiving side, there is a problem that the signal cannot pass.

An object of the present invention is to provide an optical digital transmission device which solves such a problem.

[0005]

An optical digital transmission device of the present invention is a converter for analog-digital converting a feedback voltage of a received electric signal and outputting a digital electric signal, and the digital electric signal as a transmission signal. An inserter for multiplexing, and an extractor for separating the optical reception result of the opposite station from the received electric signal,
A converter for converting the output of the extractor into an analog signal and varying the gain of the transmission side amplifier.

Further, the optical digital transmission apparatus of the present invention comprises a first converter for converting an optical signal into an electric signal, a first amplifier for amplifying an output of the first converter, and a first amplifier for the first amplifier. A feedback circuit for returning the output to the first amplifier; a second converter for analog-digital converting the output of the feedback circuit; a first extractor for extracting a synchronous clock from the output of the first amplifier; A second extractor for extracting a pulse train from the amplifier of the first extractor according to the clock of the first extractor, and a third extractor for separating the control pulse train from the output of the second extractor,
A third converter for digital-analog converting the output of the third extractor, an inserter for multiplexing the output pulse train from the second converter on the transmission signal pulse train, and an output of this inserter for the third The second which changes and amplifies the gain by the output of the converter
Of the third amplifier, the third amplifier which is changed by the output of the third converter, and the output obtained by superimposing the output of the third amplifier and the output of the second amplifier are input and converted into an optical signal. It is characterized by comprising a converter and a detector for converting the optical output of the fourth converter into electricity and inputting it to the third amplifier.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. This optical digital transmission device includes a converter 31 for converting an optical signal into an electric signal, an amplifier 32 for amplifying the output of the converter, and a feedback circuit 33 for returning the output of the amplifier to itself.
A converter 34 for analog-digital converting the output of the feedback circuit, an extractor 35 for extracting a synchronous clock from the output of the amplifier 32, an extractor 36 for extracting a pulse train from the amplifier 32 in accordance with the clock of the extractor 35, and It has a receiver composed of an extractor 37 for separating the control pulse train from the output, and a converter 38 for digital-analog converting the output of this extractor.

In this optical digital transmission apparatus, the gain is obtained by the inserter 39 which multiplexes the output pulse train from the converter 34 of the receiving unit with the transmission signal pulse train, and the output of the converter 38 of the receiving unit. Variable and amplifying amplifier 40
And an amplifier 41 for changing the gain by the output of the converter 38.
A converter 42 for inputting an output obtained by superimposing the output of this amplifier and an output of the amplifier 40 and converting it into an optical signal; and a detector 43 for converting the optical output of this converter into an electric signal and inputting it into the amplifier 41. It has a transmission part constituted by.

Next, the operation of this embodiment will be described.

The optical signal 1 is input to the converter 31, its electric output 3 is amplified by the amplifier 32, and its output 4 is fed back to the feedback circuit 3.
The output 9 through 3 is superimposed on the electrical signal 3. The output 9 of the feedback circuit 33 is converted from analog to digital by using the converter 34, and the output 14 is converted into the transmission electric output 8 by the inserter 3
In 9, the signals are multiplexed and the transmission direction electric pulse train 6 is output. On the other hand, the extractor 35 extracts the synchronous clock 13 from the output 4 of the amplifier 32. Amplifier 32 with extractor 36
The output 4 of the above is input and the signal pulse train 5 is taken out in synchronization with the synchronous clock 13. The counter station optical reception level signal pulse train 15 is decomposed from the signal pulse train 5 in synchronization with the synchronous clock 13 by the extractor 37. This pulse train 15 is input to the digital-analog converter 38, and the analog output 1
Get 6. The analog output 16 is input to a transmission direction electric pulse train amplifier 40 and a DC bias amplifier 41 that keeps the electric output constant. As a result, the amplifier 40 operates so that the gain increases when the optical reception level of the opposite station decreases,
The gain of the amplifier 41 increases or decreases in proportion to the analog output 16. The signal obtained by superimposing the output 7 obtained by amplifying the transmission direction pulse train 6 by the amplifier 40 and the output 10 of the amplifier 41 is input to the converter 42 that converts the signal into light, and the optical transmission signal 2 is output. The output 11 of the converter 42 is input to the detector 43 to obtain the electric signal 12. By amplifying this electrical signal 12, the bias voltage of the electro-optical converter is determined.

[0011]

As described above, according to the present invention, in the optical digital transmission device, the optical transmission level is changed according to the optical reception result on the opposite station side. Therefore, the optical transmission / reception is performed rather than only the reception side follows the optical level change. The range in which the levels can be adjusted becomes wider.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional optical digital transmission device.

[Explanation of symbols]

1 optical input 2 light output 3 Optical-electrical conversion output 4 amplifier output 5 Pulse train extractor output 6 AC amplifier input 7 AC amplifier output 8 Control pulse train inserter input 9 Receiver feedback output 10 DC amplifier output 11 Output for controlling electro-optical converter 12 Control optical-electrical converter output 13 Clock extractor output 14 Analog-digital conversion output 15 Opposite station optical input level information output 16 Digital-analog conversion output 31, 34, 38, 42 converter 32, 40, 41 amplifier 33 Feedback circuit 35,36,37 extractor 39 Inserter 43 detector

Claims (2)

[Claims] 1. A feedback voltage of a received electric signal is converted into an analog voltage.
A converter that digitally converts and outputs a digital electric signal, an inserter that multiplexes the digital electric signal into a transmission signal, an extractor that separates the optical reception result of the opposite station from the reception electric signal, and an output of the extractor An optical digital transmission device, comprising: a converter that performs analog conversion and performs an output that varies the gain of a transmission-side amplifier. 2. A first converter for converting an optical signal into an electric signal, a first amplifier for amplifying an output of the first converter, and an output of the first amplifier for returning to the first amplifier. A feedback circuit and a second analog-to-digital converter for the output of this feedback circuit
, A first extractor for extracting a synchronous clock from the output of the first amplifier, a second extractor for extracting a pulse train from the first amplifier according to the clock of the first extractor, and a second extractor A third extractor for separating the control pulse train from the output of the extractor, a third converter for digital-analog converting the output of the third extractor, and an output from the second converter for the transmission signal pulse train. An inserter that multiplexes pulse trains, a second amplifier that changes the gain of the output of the inserter by the output of the third converter, and a third amplifier that changes the gain of the output of the third converter And a fourth converter that inputs the output obtained by superimposing the output of the third amplifier and the output of the second amplifier and converts the output to an optical signal, and the optical output of the fourth converter to electricity. And a detector for inputting to the third amplifier. Optical digital transmission system according to.