JPS5849076B2 - Signal processing method for remote control equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal processing method 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 control commands and the button is pressed, and the signal is identified to enable the code pulse train to be activated. , 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 sending out the data for a long 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 received signal processing method for preventing malfunctions developed to solve the above-mentioned problems.

According to the method of the present invention, the arrival of a code pulse train of a received control signal is detected, and this detection causes a first code pulse train having a width that substantially falls within the pause period between the first code pulse train and the next code pulse train. 1 rectangular wave is generated, this first rectangular wave and the control signal are matched, and if a matching component due to noise exists within the pause period, a period that substantially includes this component and the next code pulse train. generate a second rectangular wave with a width of , and according to this second rectangular wave, the period of this square wave,
The control signal is blocked from being input to the decoder.

This means that if the pulse width of the second rectangular wave that determines the noise cutoff period only corresponds to the noise component that occurs during the pause period, the noise will be reduced from the pause period to the next code pulse train. If this occurs, the control signal input to the decoder is formed by a code pulse train containing noise components, resulting in a situation where a normal control command is erroneously transmitted.

That is, since this code pulse train contains noise components, it is converted into a code pulse train indicating an unexpected control command.
This is because this 11 cannot be used as a signal indicating command information.

Therefore, in the present invention, by eliminating the code pulse train following the pause period in which noise occurs, there is no need to provide a complicated circuit such as inputting an identification signal into the control signal, and safety against noise is increased.

A circuit providing the method of the present invention will be described below with reference to the drawings.

FIG. 1 is a block circuit diagram schematically showing the main parts of a remote control receiver to which the present invention is applied.

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. .

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.

A predetermined frequency is pulse code modulated using a digitally coded signal of command information, and the detector 3 demodulates it into a predetermined digital code.

This control signal is 31. in Fig. 3A. At a constant interval t as shown at 31.

It was repeatedly sent out with .

Na button, 31. 31 waveform (d) is a coded pulse train in detail, but its detailed format is not particularly treated here, so it is omitted.

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

In the decoder 5, for example, the period is t. A plurality of decoding operations are performed in response to a code pulse train that is repeated a predetermined amount in accordance with t, and two consecutive code pulse trains have a period of t.

When it is confirmed that the code pulses match, an output is sent to control the controlled unit according to the command content indicated by the code pulse train.

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

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

Control signal Fig. 3 Ipa, period 3 in which code pulse train exists
In periods other than 1.31, ie, inactive periods, it is set so that no other signals are 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 FIG. 3A is mixed in.

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

The additional circuit 20 shown in FIG. 1 is shown in a more specific configuration in FIG.

The output of the wave detector 3 (FIG. 3A) is applied to the latch circuit 16 and the NAND gate 18, and the NAND gate 18 responds to the output of the latch circuit 16 and the output of the wave detector 3.

There is a pulse generation circuit 17 comprising a monostable multiviprator triggered by the output of the single latch circuit 16;
The circuit arrangement is such that this output is given as a reset input to the latch circuit 16.

The output of the NAND gate 18 is given to set a latch circuit 19, and the output of this latch circuit 19 controls the switch made of the transistor 11.

The transistor 11 has its collector connected to the input side of the decoder 5 in the signal path of the digital code.

The output of the residual latch circuit 19 is sent to the pulse generating circuit 17 described above.
The output pulse of the circuit 10 is used as a reset input of the latch circuit 19.

When a normal control signal that does not contain any noise is received, the code pulse train 31.31 in Fig. 3A is detected, and after the code pulse train passes, the button is pressed and the latch circuit 16 is activated.
A delay means is provided at the input of this latch circuit so that the button is set.

That is, it is set after a predetermined time t1 has elapsed from the first rising edge of the code pulse train 31.

Then, the pulse generating circuit 17 is triggered by the set output of the latch circuit 16, and sends out the pulse shown in FIG. 3 after time t2.

This pulse resets the latch circuit 16, and the latch circuit 16 always sends out a rectangular wave output as shown in Figure 3 during the rest period after the code pulse train 31.31 in Figure 3A.

If no noise component is mixed into the pause period of the code pulse train 31.31, the output of the NAND gate 18 does not change, and the latch circuit 19 at the subsequent stage is reset.

Therefore, in this case, the transistor 11 is cut off so that the code pulse train is input to the decoder 5 side.

Next, when a noise component is mixed as shown at 32 in FIG. 3A, this is added to the other input of the NAND gate 18.

As a result, both inputs of the NAND gate 18 become "I", and its output changes as shown in FIG. 3B, setting the latch circuit 19 at the next stage.

It is triggered by the set output of the latch circuit 19, and after time t3, the pulse generating circuit 10 gives the latch circuit 19 a reset pulse as shown in FIG.

Therefore, the output waveform of the latch circuit 19 becomes as shown in FIG. 3E, and the transistor 11 is turned on during the period t3 of this rectangular wave.

By turning on the transistor 11, the control signal to the decoder 5 is grounded, and the decoder 5 stops the decoding operation.

Note that in order to sufficiently perform the prevention operation regardless of the position where the noise component is mixed, the latch period t3 of the latch circuit 19 is equal to the repetition period t of the code pulse train.

must be longer than

If the output of the soft latch circuit 19 is obtained with a polarity opposite to that shown in FIG.

Another embodiment of the additional circuit 20 shown in FIG. 1 is shown in FIG. 4.

The operation of this circuit can be explained using the time chart of FIG.

The output of the detector 3 in FIG. 5A 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 Fig. 5, is a NAND gate 26.
The latch circuit 28 is set by the output of this circuit 26.

The latch circuit 24 is connected to the other output of the counting circuit 22 shown in FIG.
Used to reset the command 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 latch circuit is activated by the output of the NAND gate 23, that is, the output obtained when the pulse train 31 in Figure 5A matches the pulse in Figure 5A. 24 is set.

The clock pulses of the pulse generator 21 are taken out by the NAND gate 25 according to the set output of the latch circuit 24, and are counted by the counting circuit 22.

One count output of the counting circuit 22 is obtained as a rectangular wave as shown in FIG. Ru.

The NAND gate 26 receives this rectangular wave (E) in FIG.
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 resistor 4 in FIG. 1 is applied to decoder 5 and contributes to the control.

The latch circuit 24 is reset to the other output of the counting circuit 22 in FIG. 5, and the rectangular wave output by the latch repeats at a repetition period t as shown in FIG. 5C.

and the period of the next code pulse train.

Next, if a noise component is mixed between the code pulse trains as shown by the broken line 32 in FIG. 5A, this component 32 and the output rectangular wave of the counting circuit 22 ”.

Therefore, the NAND gate 26 outputs the pulse shown in FIG. 5, 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. 5, resetting the latch circuit 28.

At this time, the output waveform of the latch circuit 28 becomes a rectangular wave as shown in FIG. It turns out.

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

In the embodiment shown in FIG. 4, the button is used as a switch means to directly control the input of the decoder 5 by the output of the latch circuit 28, but if the polarity of the output of the latch circuit is reversed, the output is In addition to elements such as transistors, this element may be used as a switch means for turning on and off the input of the decoder.

As described above, the present invention effectively prevents the remote control device from malfunctioning due to noise components mixed in the pause period between repeated code pulse trains of the control signal.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block circuit diagram schematically showing the main parts of a remote control receiver to which the present invention is applied, and FIG. 2 is a block circuit diagram showing the configuration of a circuit implementing the method of the present invention. Fig. 3 is a time chart for explaining the operation of the circuit shown in Fig. 2;
FIG. 4 is another block circuit diagram implementing the method of the present invention,
FIG. 5 is a time chart for explaining the operation of the circuit of FIG. 4. 16.19...Latch circuit, 17.10...
... Reset pulse generation circuit, 18 ... NAND gate, 11 ... Switch transistor,
31...Digital code pulse train.

Claims (1)

[Claims] 1 The transmitter side converts the command information into digital code and transmits a code pulse train that is repeated multiple times intermittently at a predetermined period with a certain pause period as a control signal, and the receiver side receives this control signal. , a remote control device that performs predetermined control by decoding that the code pulse train is repeated at the predetermined period,
detecting the arrival of a code pulse train of the received control signal and generating a first rectangular wave having a width that is substantially contained within a pause period between the first code pulse train and the next code pulse train; , the first rectangular wave and the control signal are matched, and if a matching precept exists within the rest period of the control signal, the width of the period that substantially includes this component and the next code pulse train is determined. 1. A signal processing method for a remote control device, comprising: generating a second rectangular wave having a second rectangular wave, and blocking input of the control signal to a decoder during a period of the rectangular wave according to the second rectangular wave.