Radio receiver

• US 4,525,867 A
• Filed: 01/26/1983
• Issued: 06/25/1985
• Est. Priority Date: 08/04/1980
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Shiratani, Yuji
• Primary Examiner(s): Bookbinder, Marc E.
• Application Number:
  US06/461,977
• Time in Patent Office: 881 Days
• Field of Search: 455/161, 455/194, 455/221, 455/212, 455/218, 455/225, 455/185, 455/186, 455/166, 381/94
• US Class Current: 455/194.1
• CPC Class Codes: H03G 3/341 Muting when no signals or only weak signals are present H03G3/344, H03G3/345 take precedence
• CPC Class Codes: H03G 3/348 Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
• CPC Class Codes: H03J 1/0066 with means for analysing the received signal strength H03J1/0083 takes precedence

Abstract

A control unit tunes a tuner to a broadcasting station as determined by frequency data stored in a memory and then to another broadcasting station as determined by other frequency data stored in the memory while it applies a muting pulse to a muting circuit to mute an output from the tuner for a relatively short time. Subsequently, the tuner is tuned to that station having a higher reception level. An audio level sensor connected to the tuner is connected to one input of an AND gate whose other input is supplied with an output from the control unit originating from a command muting signal. When the sensor senses that an audio level of the tuner'"'"'s output is approximating a zero level, the sensor supplies an output to the AND gate so as to permit the control unit to apply the muting signal to the muting circuit.

Claims

1. A radio receiver comprising:

an antenna for inducing a signal thereon;

a tuner means which is supplied with said signal from said antenna;

a muting circuit electrically coupled to said tuner means to mute an output from said tuner means in response to a command muting signal supplied thereto;

an audio level sensor means for sensing an audio level of an audio analog signal resulting from said output from said tuner means, said audio level sensor means being responsive to the sensed audio level of said audio analog signal which is not higher than a predetermined magnitude so as to deliver an audio level sensed signal; and

AND gate having one input connected to said audio level sensor means;

a pulse generator means for generating timing pulses at predetermined constant equal time intervals, said timing pulses acting as said command muting signal;

a latch circuit connected to said pulse generator means to latch therein said timing pulses from said pulse generator means, said latch circuit having its output connected to another input of said AND gate; and

a control unit connected to outputs of said AND gate, said latch circuit and said pulse generator means, said control unit having its output connected to both said latch circuit and said muting circuit;

wherein said latch circuit puts said command muting signal from said pulse generator means in a standby state, and said AND gate is responsive to the reception of said audio level sensed signal from said audio level sensor means so as to generate a signal for releasing said command muting signal from said standby state so as to thereby cause said control unit to supply said command muting signal to said muting circuit and to also reset said latch circuit.

2. A radio receiver as claimed in claim 1, further comprising a broadcast program changing means for changing a common broadcast program from a first one of a plurality of broadcasting stations which are respectively transmitting said common broadcast program at different frequencies to a second one of said broadcasting stations during the reception of said first broadcasting station when said muting is effected, and a means for determining a reception level of said second broadcasting station and then tuning said tuner means to said first broadcasting means while removing said muting.

3. A radio receiver as claimed in claim 1, wherein said predetermined magnitude approximates a zero magnitude.