JPS5849077B2 - Malfunction prevention device for remote control equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit device for preventing a receiver of a remote control device from malfunctioning due to noise.

As a remote control device, the transmitter side transmits a code pulse train in which digitally coded command information is repeated multiple times intermittently with a certain pause period as a control signal, and the receiver side receives this control signal and There is a system that performs predetermined control by confirming that two consecutive code pulse trains match at a predetermined period by decoding a code pulse train that is repeated several times.

Conventionally, to prevent malfunctions caused by noise in this type of device, another code signal is inserted before or after the code pulse train of information indicating a control command, and by identifying the signal, the code pulse train is validated. , has been determined to be invalid.

1. By simply transmitting such an identification signal, it may not be possible to distinguish between a code pulse train that is effective as command information and a code pulse train that is insufficient as command information due to the generation of noise. These problems have been improved by inverting the signal every cycle or by sending out the identification signal for a long period of time.

However, this required a more complex transceiver circuit, and it was not advantageous in terms of price when mass-produced.

The present invention is a malfunction prevention device developed to solve the above-mentioned problems.

According to the present invention, the first gate means matches the clock pulse sent from the pulse generator and the received control signal, the first latch circuit means is set by the match output, and the first latch circuit means is set by the set output. The aforementioned clock pulses are gated by second gating means and the gated clock pulses are applied to counting circuit means for counting.

The counting circuit means generates a rectangular wave output having a width approximately within the pause period between the pulse trains of the control signal, and a pulse located after the elapse of the repeated code pulse train that follows the initial code pulse train. do.

Then, the third gate means matches the rectangular wave output with the control signal, the gate output sets the second latch circuit means, and the pulse output of the counting circuit means sets the second latch circuit means. Reset.

As a result, in the present invention, as the output of the second latch circuit means,
It is possible to obtain a rectangular wave that matches the location where the noise component is mixed, and using this rectangular wave, the control signal input to the decoder is blocked by the switch means, and when the noise component is generated during the rest period, is to remove the code pulse train following this rest period.

In other words, noise may occur at any position during the rest period, and if the noise component occurs from the rest period to the next code pulse train, this code pulse train cannot be used as a regular control command. Can not.

Therefore, here, the code pulse train that follows the pause period in which some noise has occurred is not input to the decoder.

In this way, by excluding the code pulse train following the pause period in which noise occurs, there is no need to construct a complicated circuit for inputting an identification signal, and safety against noise is increased.

A main block circuit of a receiver of a remote control device according to an embodiment of the present invention is shown in FIG. 1 and FIG. 2, and its operation can be explained with reference to a time chart in FIG. 3.

In Fig. 1, numeral 1 is a receiving section, which is not shown, but corresponds to a light receiving element if the control signal sent from the transmitter side is infrared rays, or a microphone, etc. if it is transmitted by ultrasonic waves. do.

The control signal received and converted into an electrical signal is sent to an amplifier 2.
The signal is amplified by a predetermined amount and applied to the detector 3.

The signal is obtained by pulse code modulating a predetermined frequency using a digital coded signal of command information, and this detector 3
is demodulated into a predetermined digital code.

This control signal is repeatedly sent out at regular intervals t, as shown at 31 and 31 in FIG. 3A.

Note that the waveform 31.31 is a coded pulse train in detail, but its detailed form is not particularly treated here, so it is omitted.

The demodulated control signal A in FIG. 3 is given to the decoder 5.

In the decoder 5, decoding operations are performed several times in response to a code pulse train that is repeated a predetermined amount with a cycle t, and when it is confirmed that two consecutive code pulse trains match with a cycle t, the code It sends out an output to control the controlled unit according to the command content indicated by the string of strings.

In addition, as the decoder 5, a decoder that confirms the coincidence of three or more consecutive code pulse trains may be used.

Examples of the controlled unit include a television receiver's channel selection device, volume adjustment, brightness adjustment, and the like.

Control signal Fig. 3 Ipa, period 3 in which code pulse train exists
The period except for it31, that is, the rest period, is set so that no other signals are originally present.

However, when transmitting information from a transmitter to a receiver using infrared rays, for example, external light becomes a noise component and the detector 3
When the signal is demodulated by , a component 32 as shown by the broken line in 3rd step A is mixed in.

The present invention provides the following effects by adding a circuit indicated by 20.
In response to such noise, the decoding operation of the decoder is stopped.

The additional circuit 20 shown in FIG. 1 is shown in an embodied configuration in FIG.

The demodulated control signal A in FIG. 3 is applied to NAND gates 23 and 26 in the additional circuit 20.

Within the additional circuit 20 is a pulse generator 21 for sending out clock pulses, the output pulses of which are applied to the other input of a NAND gate 23 and to another NAND gate 25.

The output of the NAND gate 23 is applied to set the latch circuit 24, and the output of the latch circuit 24 is given as the other input of the NAND gate 25.

The output of the NAND gate 25 is given to the counting circuit 22 and counted.

One of the outputs of this counting circuit, E in Figure 3, is a NAND gate 26.
The latch circuit 28 is set by the output of this circuit 26.

The latch circuit 22 is connected to the other output of the housing counting circuit 22 in FIG.
Used to reset buttons 4 and 28.

The output of the latch circuit 28 is connected to control the input of the decoder 5 shown in FIG.

When a normal control signal containing no noise components is received, the output of the gate 23, that is, the output obtained when the pulse train 31 in Fig. 3 A and the pulse in Fig. 3 A match, Latch circuit 24 is set.

The clock pulses of the pulse generator 21 are extracted by the set output of the latch circuit 24 by the NAND gate 25 and counted by the counting circuit 22.

One count output of the counting circuit 22 is obtained as a rectangular wave as shown in FIG. 3, and this rectangular wave is generated so as to be located within the rest period between 31 and 31 of the code pulse train A in FIG.

NAND gate 26 Pako's square wave Figure 3 E and control signal No. 3
Consistent with Figure A, if there is no noise component within the pause period, no output will be obtained to set the latch circuit 28.

Therefore, the control signal transmitted through the resistor 4 in FIG. 1 is applied to the decoder 5 and contributes to the control.

The latch circuit 24 is reset to the other output of the counting circuit 22 shown in FIG. I'm trying to make it happen.

Next, if a noise component is mixed between the code pulse trains, for example, as shown by the broken line 32 in FIG. becomes the state of

Therefore, the NAND gate 26 outputs the pulse shown in FIG. 3, thereby setting the latch circuit 28.

Eventually, the other output of the counting circuit 22 passes through the inverter 27 and becomes as shown in FIG. 3, resetting the latch circuit 28.

At this time, the output waveform of the latch circuit 28 becomes a rectangular wave as shown in Fig. 3H, and if the potential of this rectangular wave is set to the ground potential, the control signal applied to the decoder 5 is blocked for the period of this rectangular wave. It turns out.

As a result, the circuit 5 stops the decoding operation to prevent malfunction.

The present invention provides the above-described circuit configuration on the receiver side to effectively prevent the remote control device from malfunctioning due to noise components mixed in the pause period between the code pulse trains of the control signal.

Note that in this embodiment, the output of the latch circuit 28 is used as a switch means to directly control the input of the decoder 5, but if the polarity of the output of the latch circuit is reversed, in addition to elements such as transistors, this switch means is used. The element may be used as a switch means to control on/off the input of the decoder.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram schematically showing the main parts of a remote control receiver to which the present invention is applied, FIG. 2 is a block circuit diagram of an embodiment of the malfunction prevention device according to the present invention, and FIG. 3 is a block circuit diagram of the circuit shown in FIG. It is a time chart for explaining the operation. 31.31... Code pulse train, 21...
...Pulse generator, 23, 25.26...1st
~Third gate means, 24, 28...first and second latch means.

Claims (1)

[Claims] 1 The transmitter side converts the command information into digital code and transmits a code string that is repeated multiple times intermittently at a predetermined period with a certain period of time as a control signal, and the receiver side receives this control signal. , a remote control device that performs a predetermined control by decoding that the code pulse train is repeated at the predetermined period, a pulse generator that sends out clock pulses, and a match between the received control signal and the clock pulse. a first latch circuit means that is set by a coincidence output of the first gate means; and a second gate means that gates the clock pulse by a set output of the first latch circuit means. The clock pulses taken out by the second gate means are counted to form a rectangular wave having a width substantially within the rest period of the control signal, and a pulse located after the elapse of the next arriving code pulse train. a third gate means for matching the rectangular wave output of the counting circuit with the control signal; and a pulse of the counting circuit that is set by the matching output of the third gate. A remote control device comprising: second latch circuit means that is reset by the output; and switch means that cuts off the control signal input to the set period decoder of the second latch circuit means. Malfunction prevention device.