Wireless receiver

• US 5,218,641 A
• Filed: 08/01/1991
• Issued: 06/08/1993
• Est. Priority Date: 08/14/1990
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kobayashi, Nobuo, Abe, Kensaku
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US07/739,237
• Time in Patent Office: 677 Days
• Field of Search: 381/79, 381/14, 381/110, 381/77, 455/343
• US Class Current: 381/79
• CPC Class Codes: H04B 10/114 Indoor or close-range type systems
• CPC Class Codes: H04R 2400/00 Loudspeakers
• CPC Class Codes: H04R 2420/07 Applications of wireless loudspeakers or wireless microphones
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

A wireless receiver has an FM receiver for receiving an infrared radiation modulated by an audio signal. The received infrared radiation is demodulated into the audio signal, which is then supplied through a power amplifier to a loudspeaker unit or a headphone unit. The wireless receiver includes a detector for detecting whether or not the infrared radiation is received. An output signal from the detector is used to turn the power supply of the FM receiver and the power amplifier on or off. The user of the wireless receiver is not required to turn the receiver on and off manually.

Claims

1. A wireless receiver comprising:

an FM receiver including a bandpass filter for receiving and passing an FM signal modulated by an audio signal and demodulating the signal passed by said bandpass filter into the audio signal;

a power amplifier for amplifying the audio signal from said FM receiver;

an electroacoustic transducer for converting the amplified audio signal from said power amplifier into acoustic energy;

a battery;

a power supply line connecting said battery to said FM receiver and said power amplifier;

a switching element connected in said power supply line in series between said battery and said FM receiver and said power amplifier;

a detector having an input connected to the signal passed by said bandpass filter for detecting whether or not there is an FM signal received by said FM receiver;

said detector comprising a narrow-band AM receiver supplied by a direct connection with the voltage of said battery as an operating voltage and including a turner tuned to the frequency of the FM signal, a negative impedance converter, and an AM detector;

the arrangement being such that said detector supplies a detected output signal as a control signal to said switching element, and

when said FM signal is detected by said detector, said switching element is turned on by said detected output signal to apply the voltage of said battery as an operating voltage to said FM receiver and said power amplifier, and at the same time said FM signal is received and demodulated into said audio signal by said FM receiver, and the audio signal is supplied through said power amplifier to said electroacoustic transducer, and

when said FM signal is not detected by said detector, said switching element is turned off by said detected output signal to stop applying the voltage of said battery to said FM receiver and said power amplifier.

2. A wireless receiver according to claim 1 wherein said FM receiver comprises means for supplying a muting signal to said power amplifier to mute the power amplifier when the FM signal is not received by said FM receiver.