JPS63200630A - Optical transmitter-receiver - Google Patents

Abstract

PURPOSE:To transmit/receive an optical signal with high quality by decreasing the time rate of the emission of a light emitting element to increase the light peak output and eliminating a low frequency zone having much invaded light component. CONSTITUTION:A pulse generating circuit 2 outputs a pulse C<+> having a pulse width t1 based on an input of a leading signal B<+> and a pulse generating circuit 3 outputs a pulse C<-> of a pulse width t2 (t1>t2) based on the trailing B<-> input. In this case, the pulse C<-> is a pulse having a pulse width t2 with a delay of t1-t2 with respect to the B<-> reference. The pulses C<+>, C<-> are synthesized and inputted to an electrooptical conversion circuit 5 as a transmission pulse D and converted into an optical pulse D'. Moreover, the time rate of pulse emission of the pulse D to the sent data A by selecting the minimum pulse width of the sent data as Tmin and selecting the relation of t1+t2<Tmin and the peak output of light is increased by the reduction of the time rate. Furthermore, the pulse D' is converted into an electric signal D'' by an optoelectric conversion circuit 6 and a low frequency component including much invaded light component is eliminated by a differentiation circuit 7.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical transceiver suitable for spatial transmission of light.

[Prior Art] In the spatial transmission of light by light intensity modulation, the most serious obstacle is the contamination of natural light such as sunlight and artificial light such as lighting into an optical receiver. Since these contaminations are received as noise, it is desirable to remove them as much as possible. Methods of noise removal include a method in which light in a wavelength range other than the wavelength band of the signal light is removed by an optical filter, and a method in which after conversion to an electrical signal, components other than the signal components are removed by an optical wave filter.

[Problem that the invention seeks to solve]

The most desirable way to remove noise is in the optical domain, but
There are problems such as the presence of a component of the same wavelength as the signal light in the mixed light, and the high cost of providing F-wave characteristics that efficiently remove components other than the signal light.

In addition, as a method for removing noise components in the electrical signal domain, the transmitted data signal is transmitted in advance by using a carrier wave to raise the signal component to a high frequency range where the electrical signal component of the mixed light is small, and then the signal component is removed on the receiving side. There is a method of extracting it using an Okinawa device.

Furthermore, as another method for separating signal light from mixed light, there is a method of making the signal light stronger than the mixed light. According to this method, the transmission power of the signal light can be increased, which is the easiest solution. In addition, if the above-mentioned countermeasures are used in common, the reception characteristics can be further improved.It is possible to increase the peak output of the light emitting diode used as a light emitting element, which generally reduces the light emitting time rate. By increasing the key output, it becomes possible to receive signal light that is higher than the mixed light.

The purpose of the present invention is to increase the peak output of light by providing means for reducing the light emission time rate of the light emitting element on the transmitting side, and to improve the quality of the two-quality light by removing the low frequency region with many mixed light components on the receiving side. An object of the present invention is to provide an optical transceiver capable of transmitting and receiving good optical signals.

[Means for solving problems]

The optical transceiver according to the present invention includes means for detecting the rising edge and falling edge of a transmitted data pulse, and generates a pulse having a pulse width t smaller than 1/2 of the minimum pulse width Tmin of the transmitted data pulse with respect to the rising edge. Then, the Tm
Means and equipment for generating a pulse having a pulse width t2 smaller than 1/2 of in and different from the t1, and the pulse width t
, and the time interval between the falling edge of the pulse with pulse width t2 is equal to the pulse width of the transmission data pulse, and then the light A? an optical transmitter for converting the electrical signal pulse into a signal; and a means for differentiating the electrical signal pulse converted from the optical signal.
means for measuring the time interval from the rising edge to the falling edge of the differentiated signal, and if the time interval is substantially t, it is determined that it is the rising edge of the transmission data pulse, and the time interval is substantially t2. If so, the optical receiver determines that the transmission data pulse is falling, sets a bistable circuit based on the rising edge determination, and resets the bistable circuit based on the falling edge determination.

Ru.

〔Example〕

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

FIG. 1 is a block diagram showing the configuration of an embodiment of an optical transceiver according to the present invention, and FIG. 2 is a waveform diagram of each part showing the operation of the embodiment of FIG. In these figures, transmission data A is input to a rising and falling separation circuit 1, and the rising portion of the data pulse is detected and input to a pulse generation circuit 2 as a rising multi-signal B+. Similarly, the falling portion of the data pulse is detected and inputted to the pulse generation circuit 3 as the falling multi-signal B-.

The pulse generating circuit 2 shown in FIG. 1 outputs a pulse C having a pulse width t1 with reference to the rising edge multi-signal B input.

The pulse generating circuit 3 in FIG. 1 outputs a pulse C- having a pulse width t2 (t,>t2) with reference to the falling signal B-human power. In addition, in this case, C- is 5 against the B- standard.
) te1. - The pulse has a pulse width t2 delayed by 12 hours.

C+ and C- are combined in the coupling circuit 4 of FIG.

Input to the electro-optical conversion circuit 5 as a transmission pulse D: h
# Light'? Convert to Luz D'. C+Pulst c-
The interval between the falling points of the pulse is equal to the pulse width of the transmission data because the C-a4 pulse is delayed by tl-t2 time in the pulse light emitting circuit 3.

Also, let Tmin be the minimum pulse width of transmission data.

As t1+t2<Tmin, the pulse generation time rate of the transmission pulse D with respect to the transmission data A decreases, and it becomes possible to increase the peak output of light by the decrease in the time rate.

The optical transmission pulse D' in FIGS.
is converted to This electrical signal DI is subjected to a differentiation circuit 7 in which low frequency components with many mixed optical components are removed, and is input as a differential wave E to time interval measurement circuits 8 and 9.

The time interval measuring circuit 8 calculates the (+) differential of the differential wave E from the (←) differential interval to t, ±Δ1/(Δt' is the judgment tolerance range)
When it is within the range of , the F signal is output. Similarly, the time interval measurement circuit 9 detects the (+) differential of the differential wave E when the differential interval is within the range of t2±Δt// (Δt is the permissible judgment range).

Output F-signal. That is, the F signal has a pulse width t(
7) d'rus and r are determined to have received a pulse with a width of t2, and the determination output is (→ Since this is the end point of differentiation, an F+ or F- signal is output at that position. .F corresponds to the rising edge of the transmitted data.

Since F- corresponds to the falling edge, the flip-flop circuit 1
By setting 0 with F+ and resetting with F- signal, reproduced transmission data G is obtained on the output side.

〔Effect of the invention〕

As is clear from the above description, the present invention has the effect of increasing the optical peak output by lowering the light emission time rate of the nine light emitting elements, and reducing mixed light components by differentiating the received signal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment according to the present invention;
FIG. 2 is a time chart showing operating waveforms of each part in the embodiment of FIG. 1. In the figure, l is a rising edge and falling edge separation circuit, 2 and 3 are pulse generation circuits, 4 is a coupling circuit,
5 is an electric-to-optical conversion circuit, 6 is an optical-to-electrical conversion circuit, 7 is a differential circuit, 8.9 is a time interval measuring circuit, and 10 is a flip-flop circuit. Figure 1 Figure 2

Claims (1)

[Claims] 1. Means for detecting the rising and falling edges of a transmission data pulse; generating a pulse having a pulse width smaller than 1/2 of the minimum pulse width T_m_i_n of the transmission data pulse for a rising edge; 1/ of T_m_i_n
means for generating a pulse with a pulse width t_2 smaller than 2 and different from said t_1, and the time interval between the falling edge of the pulse and the falling edge of the pulse with the pulse width t_2 is the transmission data pulse. an optical transmitter that converts the electrical signal pulses into optical pulses after combining them so that the pulse width is equal to the pulse width of the optical signal; a means for differentiating the electrical signal pulses converted from the optical signals; means for measuring a time interval, the time interval being substantially t_1.
If so, it is determined that it is the rising edge of the transmission data pulse, and if it is substantially t_2, it is determined that it is the falling edge of the transmission data pulse.
An optical transmitter/receiver comprising: an optical receiver that sets a bistable circuit based on a rise determination, and resets the bistable circuit based on a fall determination.