Remote-controlled receiver

• US 4,241,456 A
• Filed: 08/22/1979
• Issued: 12/23/1980
• Est. Priority Date: 08/30/1978
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Inoue, Shigeki, Nakagaki, Harushige
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US06/068,564
• Time in Patent Office: 489 Days
• Field of Search: 455/603, 358/194.1
• US Class Current: 398/106
• CPC Class Codes: G08C 23/04 using light waves, e.g. infrared
• CPC Class Codes: H04B 10/60 Receivers

Abstract

An infrared remote-controlled receiver of the type comprising an infrared sensing element for receiving a signal transmitted by means of infrared radiation, and an amplifier for amplifying the signal detected by the sensing element, is further provided with detecting means for detecting the ambient luminance of the receiver (an interference signal) and gain control means for supplying the output signal of the detecting means to the amplifier to control its gain in accordance with the ambient luminance of the receiver.

Claims

1. In an infrared remote-controlled receiver including light detecting means for receiving a remote control signal transmitted by an infrared radiation to generate a light signal corresponding to the intensity of said received signal, and an amplifier for amplifying the output light signal of said light detecting means, the improvement comprising circuit means connected to said amplifier to detect an ambient luminance of said receiver and control the gain of said amplifier in response to said detected ambient luminance of said receiver.

2. A remote-controlled receiver according to claim 1, wherein said circuit means comprises a light detecting circuit for generating a DC light current corresponding to said receiver ambient luminance, and at least one gain control circuit connected between said detecting circuit and said amplifier and operative in response to the DC light current from said light detecting circuit to control the gain of said amplifier.

3. A remote-controlled receiver according to claim 2, wherein said light detecting circuit comprises an interference illumination detecting light detecting element disposed in the vicinity of said light detecting means, and wherein said gain control circuit comprises DC light current detecting means connected to said interference illumination detecting light detecting element to detect a DC light current flowing in said interference illumination detecting light detecting element and corresponding to the intensity of an interference illumination light, switch means connected to said DC light current detecting means so as to be turned on when said detecting means detects a DC light current exceeding a predetermined value, and resistor means connected to said switch means and said amplifier whereby when said switch means is turned on a load resistance value of said amplifier is decreased and the gain of said amplifier is decreased.

4. A remote-controlled receiver according to claim 2, wherein said light detecting circuit comprises said light detecting means, and wherein said gain control circuit comprises DC light current detecting means connected to said light detecting means to detect a DC light current flowing in said light detecting means in response to an ambient luminance of said receiver, switch means connected to said DC light current detecting means so as to be turned on when said detecting means detects a DC light current exceeding a predetermined value, and resistor means connected to said switch means and said amplifier whereby when said switch means is turned on a load resistance value of said amplifier is decreased and the gain of said amplifier is decreased.

5. A remote-controlled receiver according to claim 2, wherein said light detecting circuit comprises said light detecting means, and wherein said gain control circuit comprises DC light current detecting means connected to said light detecting means to detect a DC light current flowing therein in response to an ambient luminance of said receiver, switch means connected to said DC light current detecting means so as to be turned on in response to the detection of a DC light current by said detecting means, light emitting means connected in series with said switch means to produce a light when said switch means is turend on, and photoelectric conversion means disposed opposite to said light emitting means and connected in parallel with a load resistor of said amplifier, said conversion means having a resistance value varying continuously in accordance with the intensity of the light produced by said light emitting means.

6. A remote-controlled receiver according to claim 2, wherein a plurality of said gain control circuits are connected in parallel with each other.

7. In an infrared remote-controlled receiver including light detecting means for receiving a remote control signal transmitted by an infrared radiation and an interference signal produced by an incandescent lamp light or the like to produce an AC light current and a DC light current which are respectively corresponding to the received intensity of said remote control signal and said interference signal, an amplifier for amplifying the AC light current produced by said light detecting means and a source of operating power, the improvement comprising gain control means for detecting the DC light current produced by said light detecting means to control the gain of said amplifier so as to decrease or increase the same in response to an increase or decrease in the intensity of said DC light current.

8. A remote-controlled receiver according to claim 7, wherein said gain control means comprises DC light current detecting means having a first resistor connected in series with said light detecting means and said power source to detect a DC light current flowing in said light detecting means, a second resistor having one end thereof connected to a load resistor of said amplifier, and a switching transistor connected to the other end of said second resistor and the ends of said first resistor of said DC light current detecting means whereby when a voltage drop is developed across said first resistor in response to said DC light current said switching transistor is turned on in response to said voltage drop to electrically connected said second resistor in parallel with said load resistor of said amplifier.

9. A remote-controlled receiver according to claim 7, wherein said gain control means comprises DC light current detecting means having at least series-connected first and second resistors connected in series with said light detecting means and said power source to detect a DC light current flowing in said light detecting means, at least third and fourth resistors having one ends thereof connected to a load resistor of said amplifier, a first switching transistor connected to the other end of said third resistor and the ends of said first resistor of said DC light current detecting means whereby when said DC light current produces across said first resistor a voltage drop reaching a first level value said first switching transistor is turned on in response to said first level value to electrically connect said third resistor in parallel with the load resistor of said amplifier, and a second switching transistor connected to the other end of said fourth resistor and the ends of said second resistor of said DC light current detecting means whereby when said DC light current produces across said second resistor a voltage drop reaching a second level value said second switching transistor is turned on in response to said second level value to electrically connect said fourth resistor in parallel with the load resistor of said amplifier.

10. A remote-controlled receiver according to claim 7, wherein said gain control means comprises DC light current detecting means having a first resistor connected in series with said light detecting means and said power source to detect a DC light current flowing in said light detecting means, a switching transistor connected to the ends of said first resistor of said DC light current detecting means so as to be turned on in response to the production of a voltage drop across said first resistor by said DC light current, light emitting means connected to said switching transistor to produce a light when said switching transistor is turned on, and photoelectric conversion means disposed opposite to said light emitting means and connected in parallel with a load resistor of said amplifier, said conversion means having a resistance value varying in accordance with the intensity of the light produced by said light emitting means.