JPH0993662A - Remote control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a remote control system in which oscillation or waveform distortion caused when a current signal from a terminal equipment is converted into plural voltage signals is prevented. SOLUTION: When a current signal sent from a terminal equipment 2 is received by a reception section 11, a signal received by a noise elimination section 12 is sampled for plural number of times, a signal whose pulse width is within a prescribed time is judged to be noise, the noise is eliminated and the signal whose noise is eliminated is outputted from a latch section 13. The latch section 13 detects the change in the received signal pulse and keeps the detected state for a prescribed time T1 to provide the output to a conversion section 14. The conversion section 14 converts the received signal into plural voltage signals, a supply power from a power supply section 15 to a terminal equipment 2 is superimposed on the voltage signal outputted from the conversion section 14 and the resulting signal is sent to the terminal equipment 2 from a transmission section 16 via a transmission line Ca.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote control system capable of communicating between terminals.

[0002]

2. Description of the Related Art FIG. 5 is an overall configuration diagram showing an example of a remote control system, and FIG. 6 is a signal converter 1 according to a conventional example.
It is a signal waveform diagram which shows an example of the signal input / output to / from. A plurality of terminals 2 are connected to the signal converter 1 via a pair of transmission lines Ca.

In the conventional remote control system, when the terminal device 2 communicates with another terminal device 2, as shown in FIG. 6, one terminal device 2 transmits a current signal to generate a signal. The converter 1 converts the current signal into a voltage signal and transmits the voltage signal, and the other terminal device 2 communicates by receiving the voltage signal, and the terminal device 2 itself cannot perform current-voltage conversion of the signal. .

Here, in order to simplify the construction of the terminal device 2 and prevent connection mistakes, it is necessary to make the input of the terminal device 2 non-polar. For that purpose, the transmission waveform from the signal converter 1 is changed. Need to be bipolar.

[0005]

However, in the remote control system having the above-mentioned structure, the transmission line voltage becomes 0 when the multipolar signal is switched from, for example, the + side to the − side. During the range of the minimum voltage at which the terminal device 2 operates, power cannot be supplied to the terminal device 2 and a signalless state occurs, so that the transmission waveform is broken or oscillates, and the terminal device 2 There was a problem that the signal could not be received.

FIG. 7 is a signal waveform diagram showing a case where the transmission waveform of the signal converter 1 of the remote control system according to the conventional example has a double pole. When a transmission signal as shown in FIG. 7 (d) is output from the processing circuit inside the terminal device 2, a current signal flows through the transmission line Ca, and the signal converter 1 receives the current signal at the receiving section, Output the received current signal to the transmitter,
The transmitter starts inverting the polarity of the signal. At this time, if the voltage value of the signal falls below the minimum input voltage of the connected terminal device 2 in the process of inversion, the terminal device 2 cannot be supplied with power and cannot transmit a current signal to the transmission line Ca, and the transmission line Ca As shown in FIG. 7 (c), there is no signal (no signal).

As a result, the receiving section of the signal converter 1 judges that there is no current signal, and outputs a signal to the transmitting section so as to return to the original polarity, as shown in FIG. 7B. Then, since the signal transmitted from the transmission unit exceeds the minimum input voltage of the terminal device 2, the terminal device 2 starts transmitting the current signal again,
The polarity of the transmitted signal is also inverted. The signal transmitted from the transmitter to repeat this is shown in FIG.
The transmission waveform will be as shown in.

Further, when a current flows through the transmission line Ca due to the influence of external noise and exceeds a threshold value for detecting a signal, the signal converter 1 converts this noise into a voltage signal. there were.

The present invention has been made in view of the above points, and an object of the present invention is to prevent oscillation and waveform breakage that occur when a current signal from a terminal is converted into a bipolar voltage signal. It is to provide a remote control system that can be prevented.

[0010]

According to the first aspect of the present invention,
A plurality of terminals having a transmitter for transmitting a current signal and a receiver for receiving a bipolar voltage signal, a receiver for receiving a current signal from the terminal, and a signal output from the receiver A pair of signal converters each including: a conversion unit for converting the multipolar voltage signal into a multipolar voltage signal and a transmission unit for superimposing and transmitting the power supplied to the terminal device on the multipolar voltage signal converted by the conversion unit. In the remote control system, wherein the signal converter is connected to the transmission line, and the current signal from the terminal device is converted into a bipolar voltage signal by the signal converter so that communication is performed between the terminal devices. A latch unit for detecting a change in the pulse of the signal output from the receiving unit and maintaining the detected state for a predetermined time is added, and the conversion unit outputs a bipolar signal based on the signal output from the latch unit. It is characterized by being converted into a voltage signal It is intended.

According to a second aspect of the present invention, in the remote control system according to the first aspect, a noise removing section for removing a noise component from a signal is added to the signal converter, and a signal is output from a receiving section of the signal converter. The input signal is input to the latch unit via the noise removing unit.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a signal converter 1 of a remote control system according to an embodiment of the present invention. The system configuration of the remote control system according to the present embodiment is a configuration in which a plurality of terminal devices 2 are connected to the signal converter 1 via a pair of transmission lines Ca, as in FIG. The signal converter 1 according to the present embodiment includes a receiving unit 1
1, a noise removal unit 12, a latch unit 13, a conversion unit 14, a power supply unit 15, and a transmission unit 16. The receiver 11
The current signal transmitted from the terminal device 2 is received. The noise removing unit 12 removes noise from the signal received by the receiving unit 11 and outputs it. In the present embodiment, the current signal output from the receiving unit 11 is sampled a plurality of times, and the pulse width is Those within a predetermined time are judged to be noise and are removed. Latch section 1
3 detects a change in the pulse of the current signal input from the noise removing unit 12 (point a in FIG. 2), and the predetermined time Tl
In the present embodiment, the state at the time of detection is maintained (the time from the change of the pulse of the voltage signal to the period Toff in which the terminal 2 cannot operate). The conversion unit 14 converts the current signal output from the latch unit 13 into a bipolar voltage signal. The transmission unit 16 superimposes the power supplied from the power supply unit 15 to the terminal device 2 on the voltage signal output from the conversion unit 14 and transmits the voltage signal to the terminal device 2 via the transmission line Ca.

The operation of this embodiment will be described below with reference to the drawings. FIG. 2 is an operation explanatory diagram of the remote control system according to the present embodiment. When the receiving unit 11 receives the current signal transmitted from the terminal device 2, the noise removing unit 12 samples the received signal a plurality of times and determines that the pulse width within a predetermined time is noise. The noise is removed, and the signal from which the noise is removed is output to the latch unit 13.

When the signal is input from the noise removing unit 12, the latch unit 13 detects the change in the pulse of the input signal and maintains the detected state (the state at point a in FIG. 2) for a predetermined time Tl. And outputs it to the conversion unit 14. The conversion unit 14 converts the input signal into a bipolar voltage signal, superimposes the power supplied from the power supply unit 15 to the terminal device 2 on the voltage signal output from the conversion unit 14, and transmits the voltage signal from the transmission unit 16. It is transmitted to the terminal device 2 via the line Ca.

Here, FIG. 3 is a schematic diagram showing a case where the noise removal section 12 and the latch section 13 of the signal converter 1 according to the present embodiment are realized by software by a microcomputer. The signal converter 1 according to the present embodiment, as shown in FIG.
The first circuit includes a transistor Tr1 and a PNP transistor Tr2, and the second circuit includes an NPN transistor Tr3 and a PNP transistor Tr4 and outputs a signal having a polarity opposite to that of the first circuit. A power supply Vcc is connected to the collector of Tr3, and a resistor R for limiting current is connected between the collectors of the PNP transistors Tr2 and Tr4 and ground. Further, an operational amplifier OP1 is connected to the first circuit, an operational amplifier OP2 is connected to the second circuit, and each circuit is controlled by the operational amplifiers OP1 and OP2. The reference voltage Vbb is applied to one of the input side terminals of the operational amplifiers OP1 and OP2, and the signal from the microcomputer 3 including the noise removing section 12 and the latch section 13 is input to the other terminal. Further, one terminal on the input side of the comparator CP is connected to a connection point between the collectors of the transistors Tr2 and Tr4 and the resistor R,
The reference voltage V1 is connected to the other terminal. Then, the output from the comparator CP is input to the noise removing unit 12 of the microcomputer 3.

In the remote control system shown in FIG. 3,
When the current signal received by the receiving unit 11 exceeds the threshold value, it is converted into a signal suitable for the microcomputer 3, the noise removing unit 12 and the latch unit 13 of the microcomputer 3 perform the same operation as described above, and the converting unit 14 Is converted to a bipolar voltage signal with
The power supplied from the power supply unit 15 to the terminal device 2 is superimposed and transmitted from the transmission unit 16.

FIG. 4 is a schematic diagram showing a case where the signal converter 1 of the remote control system according to the present embodiment is configured by hardware. The microcomputer 3 shown in FIG.
It is composed of a comparison unit 17 and an oscillator 18. In the present embodiment, the comparison unit 17 compares the output of the reception unit 11 and the output of the transmission unit 18, and the reception unit 1 of the N clock period is compared.
When the output of 1 is stable, the output is inverted, and in the latch unit 13, when the rising edge of the pulse of the signal input from the comparing unit 17, the state is maintained for N ′ clocks, and when it is the falling edge. By outputting the input signal, the same operation as described above is performed.

Therefore, in this embodiment, by adding the latch unit 13 to the signal converter 1, oscillation or waveform breakage that occurs when the current signal transmitted from the terminal 2 is converted into a bipolar voltage signal. Since the noise can be prevented and the noise removing unit 12 is added to the signal converter 1,
When a current flows through the transmission line Ca due to the influence of external noise,
It is possible to prevent the current signal flowing due to the influence of this noise from being converted into a voltage signal.

[0019]

According to the first aspect of the present invention, a plurality of terminals having a transmitter for transmitting a current signal and a receiver for receiving a bipolar voltage signal, and a current signal from the terminal are provided. A receiver for receiving, a converter for converting a signal output from the receiver into a bipolar voltage signal, and a transmitter for superimposing power supplied to the terminal on the bipolar voltage signal converted by the converter and transmitting the superimposed signal. A signal converter comprising a remote controller connected to a pair of transmission lines, and the current signal from the terminal device is converted into a bipolar voltage signal by the signal converter so that communication can be performed between the terminal devices. In the control system, the signal converter detects a change in the pulse of the signal output from the receiving unit, and adds a latch unit that maintains the detected state for a predetermined time, and the converting unit is based on the signal output from the latch unit. So that it can be converted into a bipolar voltage signal. It is possible to provide a remote control system capable of preventing the oscillation and waveform cracks caused by transforming the current signal from the terminal unit to a voltage signal of the bipolar.

According to a second aspect of the present invention, in the remote control system according to the first aspect, a signal remover for removing a noise component from the signal is added to the signal converter, and the signal output from the receiver of the signal converter is added. Since it is input to the latch via the noise eliminator, when a current flows in the transmission line due to the influence of external noise, it prevents the current signal flowing due to the noise from being converted into a voltage signal. can do.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a signal converter of a remote control system according to an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the remote control system according to the present embodiment.

FIG. 3 is a schematic diagram showing a case where a noise removal unit and a latch unit of the signal converter according to the present embodiment are realized by software by a microcomputer.

FIG. 4 is a schematic diagram showing a case where the signal converter of the remote control system according to the present embodiment is configured by hardware.

FIG. 5 is an overall configuration diagram showing an example of a remote control system.

FIG. 6 is a signal waveform diagram showing an example of signals input to and output from a signal converter according to a conventional example.

FIG. 7 is a signal waveform diagram showing a case where the transmission waveform of the signal converter of the remote control system according to the conventional example is bipolar.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 signal converter 2 terminal device 3 microcomputer 11 reception part 12 noise removal part 13 latch part 14 conversion part 15 power supply 16 transmission part 17 comparison part 18 oscillator Tr1 to Tr4 transistor OP1, OP2 operational amplifier CP1 comparator V1, Vbb reference voltage R resistance Ca Transmission line

Claims (2)

[Claims] 1. A plurality of terminals comprising a transmitter for transmitting a current signal and a receiver for receiving a bipolar voltage signal,
A receiver for receiving a current signal from the terminal, a converter for converting the signal output from the receiver into a bipolar voltage signal, and a bipolar voltage signal converted by the converter to the terminal. A terminal by connecting a signal converter having a transmitter for superimposing and transmitting electric power to a pair of transmission lines, and converting a current signal from the terminal device into a bipolar voltage signal by the signal converter. In a remote control system in which communication is performed between devices, a latch unit that detects a change in the pulse of the signal output from the receiving unit and maintains the detected state for a predetermined time is added to the signal converter. The remote control system is characterized in that the conversion section converts the signal output from the latch section into a bipolar voltage signal. 2. A noise removing unit for removing a noise component from a signal is added to the signal converter, and a signal output from a receiving unit of the signal converter is input to the latch unit via the noise removing unit. The remote control system according to claim 1, wherein the remote control system is provided.