JPS581342A - Receiver for remote control - Google Patents

Abstract

PURPOSE:To improve noise resistance during remote control, etc., by detecting the level of a noise component of some frequency other than the natural frequency of carrier light, and then controlling the detected level of a control signal carried through said detection. CONSTITUTION:A light signal inf of infrared rays having a natural frequency fc modulated by a control signal is converted into an electric signal S1 by a photoelectric converting circuit 1. After a signal S1 is amplified, a control component S2 centering on the natural frequency fc is outputted from a band-pass filter 3 and a noise component S3 of some frequency other than the fc is also outputted. The 1st detector 4 detects the control component S2 to output a control signal S4. The 2nd detector 6 detects the noise component S3 to output a noise signal S5. A level switch 8 inputs the control signal S4 and noise signal S5, and detects and outputs a control signal cut by a level inversely proportional to the level of the noise signal S5. Thus, the noise resisting performance of remote control is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes light having a unique frequency as a carrier wave, and uses light whose amplitude is modulated at the natural frequency, such as infrared light, in the control signal to be carried. , relates to a receiving device for a remote control system for remotely controlling a device, and was developed for the purpose of obtaining receiving sensitivity that is inversely proportional to noise components other than the above-mentioned natural frequencies.

In other words, it was developed for the purpose of improving noise resistance by detecting the magnitude level of noise components other than the natural frequency and controlling the detection level of the control signal carried by this detection. It is.

An embodiment of the present invention will be described based on the block circuit diagram of FIG. 1. l is a conversion circuit that converts an optical signal into an electrical signal, and this circuit has, for example, a natural frequency fc modulated by a control signal. An infrared optical signal inf is input and converted into an electrical signal 81. Reference numeral 2 denotes an amplifier, which inputs and amplifies the electrical signal S1 and outputs the amplified signal. Reference numeral 3 designates a band-pass filter, which input-processes the amplified electric signal S1 and outputs a component centered around the natural frequency fc, that is, a control component S2, and also outputs a component centered around the natural frequency fc.
The other components, that is, the noise component S3, are output.

4 is a first detector, and this detector input-detects the control component S2 and outputs a control signal S4.

5 is a first filter, and this filter filters and outputs the control signal S4.

6 is a second detector, which input-detects the noise component S3 and outputs a noise signal S5. 7 is a second filter, which filters and outputs the noise signal S5.

8 is a level switch circuit, which receives the control signal S4 and a DC level signal proportional to the noise signal S5, detects and outputs the control signal cnt at a level inversely proportional to the level of the noise signal S5. do.

The electronic circuit diagram shown in FIG. 2 specifically shows the block circuit of FIG. 1 described above, and reference numerals in the figure that correspond to those in FIG.

Dl in FIG. 2 is a photodiode constituting the photoelectric conversion circuit 1, and this diode receives an optical signal inf and converts it into an electrical signal. Trl is also a transistor for the middle of the conversion circuit 1, and this transistor amplifies the converted electric signal Sl and outputs the amplified signal.

R1 is a resistor that constitutes the bandpass filter 3, C,
, C, are capacitors constituting the filter 3, and L
, is an inductance constituting the filter 3.

D2 is a detection diode constituting the first detector 4, which inputs and detects the control component S2. C8 and R2 are capacitors and resistors, which constitute the first filter 5.

D is a detection diode constituting the second detector 6, which inputs and detects the noise component S3. R4 and C4 are resistors and capacitors, and they constitute the second filter 7.

TR2 is a switching transistor constituting the level switch circuit 8. A control signal S4 is applied to the base of this transistor, and a voltage level resistor R6 is interposed at the emitter, so that the DC signal detected by the noise signal is A signal level S5 is applied, and a control signal cnt is sent from the collector.
is output.

One aspect of the present invention having the above configuration is that the voltage of the resistor R6 changes depending on the detected DC signal level S5 of the noise signal proportional to the noise component S3, and this voltage change causes the voltage of the transistor TR2 of the level switch circuit 8 to change. The operating level will change.

Therefore, the level of the noise signal S5 is detected via the resistor R6, while the detected level of the control signal S4 corresponding to the control component S2 is detected through the resistor R6 and the transistor TR.

As a result, when the noise component is small, the apparent gain of the control signal can be increased, and when the noise component is large, the noise resistance characteristics of the control signal can be improved. There is.

As mentioned above, the present invention is capable of separating and detecting a control signal component in which a control signal and a noise component (for example, noise caused by fluorescent light, etc.) are present, and a noise component. Even when a control signal is sent, the operation of the level switch circuit can be maintained in the same state as when only the noise component is detected, and the level switch for detecting the control signal is inversely proportional to the size of the noise component, regardless of the presence or absence of the control signal. It is possible to provide a circuit.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing one embodiment of the present invention, and FIG.
The figure is a concrete electronic circuit diagram of the block diagram of the same as above. DESCRIPTION OF SYMBOLS 1...Conversion circuit, 3...Band pass filter, 4...First detector, 6...Second detector, 8... ...Level switch circuit. Patent applicant Shin Nihon Electric Co., Ltd.? ! Sekisho 58-1342 (3)

Claims (1)

[Scope of Claims] A receiving device for a remote control system that performs remote control via carrier wave light having a unique frequency modulated by a control signal, the receiving device comprising: A conversion circuit that converts an optical signal into an electrical signal and outputs it, and a bandpass that inputs and processes the electrical signal and outputs it separately into a control component centered on the above-mentioned natural frequency and other noise components. a filter; a first detector that input-detects the control component and outputs a control signal; a second detector that input-detects the noise component and outputs the noise signal level as a DC level signal; a level switch circuit which inputs a control signal of the noise signal and also receives the DC level signal and detects and outputs the control signal at a level threshold that is inversely proportional to the level of the noise signal. Receiving device for control.