JPH0314258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an input terminal device for inputting contact information to a transmission system in an optical information transmission system that collects information on a plurality of contact points.

A conventional device of this type was constructed as shown in FIG.

That is, the optical pulse signal A input from the optical input terminal 1 passes through the optical branch 2 and is transmitted to each optical delay circuit 3-1 to 3-.
n, enters the optical contacts 4-1 to 4-n after a delay of their own specific delay times τ ₁ to τ _o , and only the ON signal from the optical contacts further passes through the optical combining circuit 5 to the optical output terminal 6.
Output to. Depending on the presence or absence of a pulse in the optical output from the optical output terminal 6 at a certain time, it is possible to determine whether the corresponding optical contact is on or off.

However, with this conventional device, it is not possible to obtain a synchronization signal for making correspondence between the optical pulse train output to the optical output terminal and each optical contact, and therefore, for example, as shown in FIG. In the information gathering terminal 20, it was necessary to synchronize the optical transmitter 21 and the optical receiver 22 using a synchronization signal generator 23. This is not only complicated;
For example, the contact information collection terminal 20 and the contact input terminal 10
If the distance between the optical signal and the optical signal changes, the delay time of the optical signal that occurs during this period changes accordingly, resulting in inconveniences such as the need to resynchronize.

In order to eliminate these drawbacks, the present invention allows the contact input terminal device itself to output a synchronization signal, and will be described in detail below with reference to the drawings.

FIG. 3 is a block diagram of a contact input terminal device exemplified to explain the technical content of the present invention step by step, in which 1 is an optical input terminal, 2 is an optical branch, 3 and 3-
1 to 3-n are optical delay circuits, 4-1 to 4-n are optical contacts, 5 is an optical combining circuit, and 6 is an optical output terminal.
In addition, the optical delay circuits 3 and 3-1 to 3-n each have τ ₀ to
A delay time of τ _o is given to the optical signal, and the following relationship holds between each delay time.

τ ₀ <τ ₁ , τ ₂ , ...τ _o (1) Now, the optical pulse input from the optical input terminal is branched at the optical branch and becomes a signal delayed by a predetermined time in each delay circuit. Next, the optical pulse signal input to the delay circuit 3 is not cut off, and is outputted to the optical output terminal earlier than the signal input to any other delay circuit due to the relationship of equation (1). On the other hand, other delay circuits 3-1 to 3-n
The optical signal that enters is output to the optical output terminal only if the subsequent optical contacts are ON.

That is, in this optical contact input terminal, one optical pulse signal is always output after a specific delay time τ ₀ due to the input of the optical pulse signal, and following this optical pulse signal, each optical contact is turned on and off. A corresponding optical pulse train is output.

Therefore, when using this contact input terminal device, if synchronization is achieved using the first pulse signal output after optical input, it is possible to easily correspond between subsequent pulse trains and each contact. . In this way, in this contact input terminal device, the end point itself outputs the synchronization signal first, so it can be used as a contact information collection terminal and an optical contact input terminal, as seen in the conventional device shown in Figure 2. No matter how the distance between them changes, there is no need to resynchronize them, and the transmission system has the advantage of being flexible in its configuration. In addition, since the first pulse signal for synchronization is never disconnected, for example, the presence or absence of this synchronization pulse signal may occur even if the transmission line between the contact input terminal device and the information collection terminal is accidentally disconnected. It also has the advantage of being more detectable.

FIG. 4 shows an embodiment of the present invention, in which 1 is an optical input terminal, 2 is an optical branch, 3 is a group of optical delay circuits for obtaining a synchronizing signal, and there are two optical delay circuits, τ ₀₁ and τ ₀₂ . It consists of a delay circuit.

3-1 to 3-n are optical delay circuits providing delay times τ ₁ to τ _o , respectively, 4-1 to 4-n are optical contacts, 5 is an optical combining circuit, and 6 is an optical output terminal. Delay time τ ₀₁ ,
The following relationship holds between τ ₀₂ and τ ₁ to τ _o .

τ ₀₁ ＜τ ₁ , τ ₂ , …τ _o ……(2) τ ₀₂ ＜τ ₁ , τ ₂ , …τ _o ……(3) Also, τ ₀₁ and τ ₀₂ are selected as follows. .

τ ₀₁ −τ ₀₂ =t (4) Here, t is the pulse width of the optical pulse to be input to this terminal. Also, which two of τ ₀₂ , τ ₁ to τ _o
The difference between the delay times is also selected to be larger than the optical pulse width t. The operation of this terminal is as follows. An optical pulse signal having a pulse width t inputted from the optical input terminal 1 is branched by an optical branch, and a portion enters the optical delay circuit group 3. Since the delay time of the two delay circuits constituting the optical delay circuit group 3 satisfies equation (4), the pulse width of the optical signal output from the optical delay circuit group 3 and optically combined is exactly twice the pulse width of the input pulse. is converted into a pulse signal with a pulse width of .

Now, the optical signals branched by the optical branch 2 and input to the other delay circuits 3-1 to 3-n are respectively subjected to predetermined delay times τ ₁ to τ _o , and then sent to the optical contacts 4-1 to 4-n. Among those whose optical contacts are on, they are output to the optical merging circuit to form a pulse train corresponding to each delay time. Now, since the delay time difference between any two of τ ₀₂ and τ ₁ to τ _o is larger than the optical pulse width t, the pulse train output from the optical output terminal is a pulse that has passed through the optical delay circuit group 3 for obtaining a synchronization signal. All pulses have a pulse width t, except that the pulse width 2t has a pulse width 2t.
Also, since equations (2) and (3) hold true, the pulse with a pulse width of 2t for this synchronization is positioned at the beginning of the pulse train. Therefore, if synchronization is achieved using an output pulse whose pulse width is twice that of the input pulse, the subsequent pulse train and each contact point can be easily matched.

In this embodiment, unlike other pulse signals, the synchronization pulse signal has a clear feature of having twice the pulse width, so the contact point was used as an example to explain the technical content of the invention in a step-by-step manner. It has the advantage that synchronization is possible by detecting only the optical output without the need for information on when optical pulses are input to the contact input terminal device, as in the case of an input terminal device.

As described above, the contact input terminal device according to the present invention includes an optical delay circuit group in which optical delay circuits with delay times τ ₀₁ and τ ₀₂ are inserted and connected to each of two optical transmission lines among a plurality of optical transmission lines. The relationship between the delay times τ ₁ to _{τ o} of the optical delay circuits provided and inserted and connected to each of the plurality of optical transmission lines of n systems other than these two optical transmission lines and the pulse width t of the optical pulse signal. Since we set τ ₀₁ < τ ₁ ~ _{τ o} τ ₀₂ < τ ₁ ~ _{τ o} τ ₀₁ − τ ₀₂ = t, the pulse train from the optical output terminal has a pulse with a pulse width of 2t at the beginning, and all other pulses are The present invention has the effect of providing a contact input terminal device that can output a pulse train formed of pulses with a pulse width t, and can detect ON/OFF information of each optical contact by detecting only this output.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional contact input terminal, Fig. 2 is a block diagram of an optical transmission system using a conventional optical contact input terminal device, and Fig. 3 is for explaining the technical content of this invention step by step. FIG. 4 is a block diagram showing an embodiment of the optical contact input terminal device according to the present invention. In the figure, 1 is an optical input terminal, 2 is an optical branch, 3 and 3
-1 to 3-n are delay circuits, 4-1 to 4-n are optical contacts, 5 is an optical combining circuit, 6 is an optical output terminal, and 10 is a contact input terminal device. In the drawings, the same or corresponding parts are designated by the same reference numerals.

Claims (1)

[Scope of Claims] 1. A light input terminal, a light output terminal, and a plurality of lights connected to the light input terminal and connected to an optical pulse signal having a pulse width t input from the light input terminal. an optical branching means for distributing to the transmission lines; and an optical delay circuit group consisting of optical delay circuits with delay times τ ₀₁ and τ ₀₂ inserted and connected to each of the two optical transmission lines among the plurality of optical transmission lines; , which are inserted and connected to each of the plurality of optical transmission lines of n systems other than the two optical transmission lines, and intermittent the optical pulse signals of the optical delay circuits and optical transmission lines each having a delay time τ ₁ to _{τ o} . The light combining means connects the plurality of optical transmission lines together to the light output terminal, synthesizes the optical pulse signals of the optical transmission lines, and outputs the synthesized light pulse signals from the light output terminal. Delay times τ ₀₁ , τ ₀₂ and τ ₁
A contact input terminal device characterized in that the following relationship exists between τ _o and pulse width t: τ ₀₁ < τ ₁ ~ _{τ o} τ ₀₂ < τ ₁ ~ _{τ o} τ ₀₁ −τ ₀₂ =t.