JPH0671234B2 - Optical and electrical signal receiving circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to an interface circuit used in an optical and electric signal transmission circuit.

[Conventional technology]

FIG. 4 is a diagram showing an interface circuit of a conventional transmission circuit, for example, (1) is an internal control circuit that executes various controls by signals from the transmission circuit, and (2) is an electrical signal of the internal control circuit (1). (4) An optical transmission converter for converting the optical signal into an optical signal and outputting it to the transmission circuit, (3) An optical reception converter for converting the optical signal of the transmission circuit into an electric signal and outputting it to the internal control circuit (1), (4) Is a receiver circuit that converts a two-phase electric signal of the transmission circuit into a one-phase electric signal and outputs the one-phase electric signal to the internal control circuit (1),
(5) is a driver circuit that converts the one-phase electric signal of the internal control circuit (1) into a three-phase electric signal and outputs the three-phase electric signal to the transmission circuit.
0) is a first adapter composed of an optical transmission converter (2) and an optical reception converter (3), and (11) is a second adapter composed of an optical transmission converter (2) and a receiver circuit (4). Adapter, (12) is a third adapter including a driver circuit (5) and an optical receiving converter (3), and (13) is a fourth adapter including a driver circuit (5) and a receiver circuit (4). Is an adapter.

Next, the operation will be described. When the internal control circuit (1) transmits / receives signals to / from other devices via the transmission circuit, for example, in the interface circuit shown in FIG. 4, the first adapter (10) is changed by the transmission / reception method. ~ Fourth
Four methods of adapters (13) are used.

Here, for example, when transmitting and receiving only by an optical signal, the first adapter (10) is connected to the IN and OUT terminals of the internal control circuit (1). And the OU of the internal control circuit (1)
The electric signal output from the T terminal is input to the optical transmission converter (2), converted into an optical signal and sent to the transmission circuit.
The optical signal of the transmission circuit is input to the optical receiving converter (3) and converted into an electric signal, and then input to the IN terminal of the internal control circuit (1).

Next, for example, in the case of transmitting and receiving only with an electric signal, if the first adapter (10) described above is attached to the fourth adapter (13) and changed, the transmission and reception with only an electric signal will be performed in the same manner as above. I can do it.

[Problems to be solved by the invention]

Since the interface circuit of the conventional transmission circuit is configured as described above, one set must be selected from the first adapter (10) to the fourth adapter (13) depending on the type of transmission signal. , The internal control circuit (1) for the above adapter
However, there was a problem that the contact reliability of the contact portion when it was attached to was reduced.

The present invention has been made to solve the above problems, and includes a first adapter (10) to a fourth adapter (13).
It is an object of the present invention to obtain an interface circuit that can improve the contact reliability of the contact portion while eliminating the need for selection.

[Means for solving problems]

An optical signal and electric signal receiving circuit according to the present invention is
A converter for converting the optical signal sent from the optical signal transmission line into an electric signal while being inputted from the input side,
A receiver circuit to which an electric signal sent through an electric signal transmission path is input, and a logical sum circuit that takes the logical sum of the output of the converter and the output of the receiver circuit are provided, and the receiver circuit is the input side of this receiver circuit. Has a resistor whose one end is connected to the other end and which is connected to a power supply of a predetermined voltage at the other end, and the converter has a predetermined cap that prevents the intrusion of an optical signal at the input side of the converter when the optical transmission line is removed. It is designed so that it can be installed.

[Action]

The optical signal and electric signal receiving circuit according to the present invention is
A converter that converts an optical signal sent through an optical signal transmission line into an electric signal, a receiver circuit to which the electric signal is input, a logical sum circuit that takes the logical sum of the output of the converter and the output of the receiver circuit, The receiver circuit has a resistor having one end connected to the input side and the other end connected to a power supply of a predetermined voltage, and the converter prevents the intrusion of an optical signal to the input side when the optical transmission line is removed. Certain caps can be fitted to block.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. First
In FIG. 2 and FIG. 2, the same reference numerals as those in FIG. In the figure,
(20) is an OR gate that takes the logical sum of the output signals of the optical receiving converter (3) and the receiver circuit (4), and (30) is composed of the optical transmitting converter (2) and the driver circuit (5) An output interface (40) is an input interface including an optical receiving converter (3) and a receiver circuit (4).

Next, the operation will be described. When transmitting and receiving only with optical signals, as shown in FIG. 1, an optical transmission converter (2)
And the input of the optical receiving converter (3) are respectively connected to the transmission circuit. Further, for example, in the case of transmitting and receiving only with electric signals, the receiver circuit (4) as shown in FIG.
Input and output of the driver circuit (5) are respectively connected to the transmission circuit, and a cap or the like is attached to the input side of the optical receiving converter (3) to prevent excessive light from being input. ) Output becomes zero, and stable transmission and reception of electric signals can be performed. Even when transmitting and receiving by optical signal and electric signal as above, the output interface (30)
Alternatively, by properly using the input interface (40), each combination can be performed.

In the above embodiment, the input side was left open when the receiver circuit (4) was not used.
As shown in FIG. 3, a pull-down resistor (22) is provided in the non-inverting element of the receiver element (4) and a pull-up resistor (21) is provided in the inverting element, so that the output of the receiver element (4) is zero. If set to, more stable reception of optical signals can be performed. Needless to say, the same effect as in the above embodiment can be obtained by using another method instead of the pull-up resistor (21) and the pull-down resistor (22).

〔The invention's effect〕

As described above, according to the present invention, a converter that converts an optical signal sent through an optical signal transmission line into an electric signal, a receiver circuit to which the electric signal is input, an output of the converter and an output of the receiver circuit And a logical sum circuit that takes a logical sum of
The receiver circuit has a resistor whose one end is connected to the input side and whose other end is connected to a power supply of a predetermined voltage, and the converter is designed to prevent the intrusion of an optical signal to the input side when the optical transmission line is removed. Since the cap can be attached, there is an effect that the inconvenience of handling that a dedicated adapter is prepared depending on the signal to be transmitted can be ameliorated and a decrease in reliability can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a connection diagram showing an interface circuit according to an embodiment of the present invention, and FIG. 2 is a connection diagram showing another connection state showing an interface circuit according to an embodiment of the present invention. Three
FIG. 4 is a connection diagram of an interface circuit showing another embodiment of the present invention, and FIG. 4 is a connection diagram showing a conventional interface circuit. In the figure, (30) is an output interface and (40) is an input interface. The same reference numerals in the drawings denote the same parts.

Claims (1)

[Claims] 1. An optical signal sent through an optical signal transmission line is inputted from an input side, and a converter for converting the optical signal into an electric signal and an electric signal sent through the electric signal transmission line are inputted. A receiver circuit, and an OR circuit that ORs the output of the converter and the output of the receiver circuit, and the receiver circuit has one end connected to the input side of the receiver circuit and the other end connected to a power supply of a predetermined voltage. In addition to having a connected resistor, the converter can be equipped with a predetermined cap that prevents the intrusion of an optical signal at the input side of the converter when the optical transmission line is removed. Circuit for receiving optical and electrical signals.