JPH03244234A - Bidirectional optical transmitter - Google Patents

Abstract

PURPOSE:To attain the adjustment of the quantity of light in a short time without requiring a manual light emitting part by emitting the light emitting part at first with the maximum quantity of light according to a reset signal to be generated after turning a power source on, and executing the light quantity control of light emission optimum for reception with an activated control part. CONSTITUTION:When the power source is turned on, a power-on reset part 9a generates and outputs one reset signal Ra. A comparator 11a compares a reception signal IIa with a reference voltage VC and when the reception signal is larger than the reference voltage VC, a comparate signal ICa with a logic value '1' is outputted. According to the reset signal Ra, a control part 10a is reset and activated and while receiving a reception terminal signal ITa and the ICa, sequential operations are executed to output a busy signal Ba, test signal Ta and down signal Da to a light quantity control part 8a. When the reset signal Ra is received, the light quantity control part 8a makes a light emitting part 3a emit at a maximum and outputs a light quantity control signal Ca so as to dim the light emitting part 3a in proportion to the input time of the down signal Da.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a bidirectional optical transmission device.

[Conventional technology]

Conventionally, in this type of bidirectional optical transmission device, an optical cable 4a and an optical cable 4b are provided between an A-side optical transmission device and a B-side optical transmission device that face each other, as shown in the authority diagram in FIG. Each of the A-side optical transmission device and the B-side optical transmission device,
Light emitting parts 3a and 3b, light amount setting parts 13a and 13b
, a light receiving section 5a and 5tP logic conversion sections 6a and 6b are provided. In this it, when a transmission signal is given to the transmission terminal 1a or 1b, the light emitting section 3a
or 3b emits light, and the light receiving unit 5b or 5a receives a signal IIb or Il via the optical cable 4a or 4b,
Output. These signals are processed by the logic converter 6b or 6a.
The signal is converted into a logical signal and output from the receiving terminal 7b or 7a. Figure 4 (a) and (b)
shows the received signal IIゎ or Il, which is the output of the light receiving section 5b or 5a, and the signal level of the receiving terminal 7b or 7a when the light amount setting in the light amount setting section 13a or 13b is appropriate and when the light amount setting is inappropriate. When the light amount setting is appropriate as shown in FIG. 4Ig(a), a receiving terminal output is obtained, but when the light amount setting is inappropriate as shown in FIG. 4(b), no receiving terminal output is obtained. Note that the appropriate amount of light varies depending on the lengths of the optical cables 4a and 4b (and (b), and the amount of light is adjusted using gll and hoe.

[Problem to be solved by the invention]

In the conventional bidirectional optical transmission device described above, it is necessary to set an appropriate amount of light depending on the length of the optical cable using the light amount setting section, and it is difficult to set the appropriate amount of light, and the length may change after setting the amount of light. If it changes, it needs to be adjusted again, which has the disadvantage of requiring a large amount of adjustment man-hours.

[Means to solve the problem]

The bidirectional optical transmission device of the present invention includes two sets of optical transmission devices each having a light emitting section, a light receiving section, and a logic conversion section that converts the output of the light receiving section into a logical value. In each optical transmission device of the bidirectional optical transmission device connected with , a light amount control means that causes the light emitting unit to emit light to the maximum level when receiving the reset signal, and sequentially reduces the light emission of the light emitting unit while receiving the down signal; a comparison means for outputting a comparison signal; receiving the reset signal, outputting the busy signal and outputting the test signal; and determining one of two control procedures depending on the time point at which the comparison signal is received; Using the signal and the output signal of the logic converter as input control signals, the test signal and the down signal are sequentially controlled according to the determined control procedure to set the control value of the light amount control means, and then the busy signal is output. and a control means for stopping.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which an A-side optical transmission device and a B-side optical transmission device connected by optical cables 4a and 4b are configured in contrast, and a is added to the reference numeral. The blocks marked with b indicate the A-side optical transmission equipment, and the blocks marked with b indicate the B-side transmission equipment. To explain the configuration using the A-side optical transmission device as an example, the line switching section 2a receives the transmission signal from the transmission terminal 1a and the control section 1.
The input of the test signal Ta from the controller 10a is switched by the busy signal B from the control unit 10a and output. The light emitting unit 3a receives °“1” output from the line switching unit 2a,
It is output as light corresponding to the light amount control signal C1 from the light amount control section 8a. The light receiving section 5a receives light input from the optical cable 4b, and receives received signals I1. corresponding to the optical input. Output. The logic converter 6a converts the received signal I1. The power-on reset section 9a outputs one reset signal R1 when the power is turned on.The comparator 11a outputs a reception terminal signal IT with a logical value of "1" or "0°". I1. is compared with the reference voltage VC, and the reference voltage ■
. When it is larger, a comparator signal IC with a logical value of "1" is output. The control section 10a is reset and activated by the reset signal R, and receives the reception terminal signal IT and the comparison signal IC, and sends a busy signal Ba+test signal T and a down signal to the light amount control section 8a. The light amount control section 8a, which performs the sequential operation of outputting, causes the starting section 3a to emit light to the maximum level when receiving the reset signal R1, and outputs a light amount control signal that causes the light emitting section 3a to emit light in proportion to the input time of the down signal R1. Output C1.

FIG. 2 is a sequence diagram of the operation of the embodiment shown in FIG. 1, and shows the case where the B-side optical transmission device is powered on after time t1 when the A-side optical transmission device is powered on. The operation of FIG. 1 will be explained below with reference to FIG. 2. In response to the reset signal R1 from the power-on reset section 9a, the light amount control section 8a causes the light amount control signal C to cause the light emitting section 3a to output the maximum amount of light. , to control. Further, the control section 10a sets the busy signal B and the test signal T to "1", so that the light emitting section 3a emits the maximum amount of light.

At the same time as this control, since the comparison signal IC and the receiving terminal signal IT are both "O", the control section 10a determines that the control section 10a has risen first. After that, in response to the reset signal Rh from the power-on reset section 9b, the light amount control section 8b turns on the light emitting section 3.
Control the light amount control signal Cb so that b outputs the maximum light amount,
The control section 10b sets the busy signal Bb and the test signal Tb to "1", so that the light emitting section 3b emits the maximum amount of light. Simultaneously with this control, the control unit 10b determines that the comparator signal ICb and the receiving terminal signal Tb have both risen at "1°", so that they have risen later.After the time t2 for this confirmation, Control part 1
0b sets the test signal Tb to "0'°.The test signal T
When b becomes "0", light emission from the light emitting section 3b is cut off, and the comparator signal IC and the receiving terminal signal IT are output.

Both become °“O”′. Here, the control section 10a
starts adjusting the light intensity. That is, after a time t3 after the test signal Tb becomes 0'', the control section 10a sets the down signal to "1", so that the light amount control signal C1 starts to fall, and in accordance with this fall, the received signal IIb also falls. However, when the received signal IIb reaches the reference voltage VC at a time j4a after the down signal R becomes "'1", the comparator signal ICb becomes °'0°.Therefore, the control section 10b During time T5b, test signal T
When the test signal Tb becomes "1" and the light emitting section 3b emits light, both the receiving terminal signal IT and the comparator signal IC become "1", and the control section 10a outputs a down signal. is set to "O" to fix the value of the light amount control signal C1, and the adjustment of the light amount control signal C11 is completed.

Next, the controller unit 10b sets the down signal Db to “1”.
and lowers the light amount control signal Cb. This drop causes the received signal I1. descends, time T.

When the comparator signal IC, becomes "0" after , the control section 10a outputs the test signal T, to "0" for a time j5m.
1" and waits for a response. When the test signal Ta becomes "1" and the light emitting section 3a emits light, the reception terminal signal I T b and the comparator signal IC5 both become "1", and the control section 10b outputs the down signal Db. After 0 time t5. at which the value of the light amount control signal Cb is fixed as "O" and the adjustment of the light amount control signal Cb is completed, both the control units 10a and 10b perform all adjustments by ORing the busy signals B and Bb. finish.

〔Effect of the invention〕

As explained above, the present invention first causes the light emitting section to emit light at the maximum amount in response to a reset signal generated when the power is turned on, and the activated control section receives information from the light receiving section after the opposing transmission device is powered on. The control unit performs sequential control in conjunction with the control unit of the opposing transmission device based on the signal, and controls the light intensity of the light emitted to the optimum level for reception regardless of the length of the optical cable. This has the effect of allowing adjustments to be made in a short time without requiring any adjustments.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
Fig. 3 is a typical configuration country of conventional bidirectional transmission equipment, Fig. 4 (a) and (b) is a sequence diagram of the operation of the
FIG. 3 is a diagram for explaining signal levels in the diagram. la, lb... Transmission terminal, 2a, 2b... Line switching section, 3a, 3b... Light emitting section, 4a, 4b... Optical cable, 5a, 5b... Light receiving section, 6a, 6b... ...Logic converter, 7a, 7b...Reception terminal, 8a, 8b...
Light amount control section, 9a, 9b... power-on reset section,
10a, 10b・-control section, lla, 11b・
... Comparator, 12a, 12b... Bus terminal,
13a, 13b... Light amount setting section.

Claims (1)

[Claims] Each bidirectional optical transmission device includes two sets of optical transmission devices each having a light emitting section, a light receiving section, and a logic conversion section that converts the output of the light receiving section into a logical value, and the light emitting section and the light receiving section are connected to each other by an optical cable. The optical transmission device includes a line switching means that switches a transmission signal input to the light emitting section to a test signal using a busy signal, a power-on reset means that outputs a reset signal when the power is turned on, and a power-on reset means that switches the light emitting section when receiving the reset signal. a light amount control means for emitting light at the maximum level and sequentially reducing the light emission of the light emitting part while receiving a down signal; a comparison means for outputting a comparison signal when the received signal from the light receiving part is higher than a certain voltage; After receiving the reset signal, outputting the busy signal and outputting the test signal, and determining one of two control procedures depending on the time point at which the comparison signal is received, inputting the comparison signal and the output signal of the logic converter. It is characterized by comprising a control means that sequentially controls the test signal and the down signal as a control signal according to the determined control procedure to set a control value of the light amount control means and then stops outputting the busy signal. Bidirectional optical transmission equipment.