Noise reducing receiver device

• US 5,091,954 A
• Filed: 02/20/1990
• Issued: 02/25/1992
• Est. Priority Date: 03/01/1989
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kimura, Akira, Ohkubo, Masashi, Sasaki, Tooru
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US07/482,250
• Time in Patent Office: 735 Days
• Field of Search: 381/71, 381/72
• US Class Current: 381/72
• CPC Class Codes: G10K 11/17827 Desired external signals, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 11/17885 additionally using a desired external signal, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 2210/108 Communication systems, e.g. where useful sound is kept and noise is cancelled
• CPC Class Codes: G10K 2210/1081 Earphones, e.g. for telephones, ear protectors or headsets
• CPC Class Codes: G10K 2210/3011 Single acoustic input
• CPC Class Codes: G10K 2210/30232 Transfer functions, e.g. impulse response
• CPC Class Codes: G10K 2210/3217 Collocated sensor and cancelling actuator, e.g. "virtual earth" designs

Abstract

The present invention is concerned with a receiver device for converting electrical signal from a headphone, a telephone receiver or the like into acoustic signals. More particularly, it relates to a noise reducing receiver device in which acoustic signals in the vicinity of an electro-acoustic transducer element are converted by a microphone into electrical signals and negatively fed back to an amplifier circuit which is adapted for amplifying input electrical signals and supplying the amplified signals to the electro-acoustic transducer element. In the noise reducing receiver device, the input electrical signals are amplified by the amplifier circuit and converted by the electro-acoustic transducer element into output acoustic signals. A microphone is arranged in the vicinity of the electro-acoustic transducer element and adapted for converting the output acoustic signals and external noise into electrical signals, which are negatively fed back to the amplifier circuit via a feedback circuit. The output acoustic signals may be heard at a desired noise reduction level by adjusting the transfer function H of the electro-acoustic transducer element, the transfer function A of the amplifier circuit, the transfer function M of the microphone and the transfer function β of the feedback circuit within a range determined by |AHMβ|>>1.

Claims

1. A noise reducing receiver device, comprising;

electro-acoustic transducing means for converting electrical signals into acoustic output signals and having a transfer function H;

amplifying means having a transfer function A for amplifying electrical signals and supplying the amplified electrical signals to said electro-acoustic transducing means;

microphone means for converting output acoustic signals from said electro-acoustic transducing means together with acoustic noise in the vicinity of said electro-acoustic transducing means into electrical signals, said microphone means having a transfer function M and comprising a first microphone means having a first diaphragm and a second microphone means having a second diaphragm, the first and second diaphragms being disposed in mutual proximity and in opposition to each other; and

feedback means having a transfer function β

for negatively feeding back electrical signals produced by said microphone means as an input to said amplifying means, wherein least one of said transfer functions is adjustable within a predetermined range such that |AHMβ

| >

1.

2. The noise reducing receiver device according to claim 1, wherein said amplifying means comprises variable gain amplifying means having a gain as said transfer function A which is variably adjustable within a range determined by |AHMβ

| >

1.

3. The noise reducing receiver device according to claim 1, wherein the transfer function β

of said feedback means is adjustable within a range determined by |AHMβ

| >

1.

4. The noise reducing receiver device according to claim 1, wherein said electro-acoustic transducing means comprises a headphone.

5. The noise reducing receiver device according to claim 1, wherein said electro-acoustic transducing means comprises a speaker means of a telephone handset.

6. The noise reducing receiver device according to claim 1, wherein said microphone means includes first and second output terminals and each of said first microphone means and said second microphone means is provided with a respective first polarity output terminal and a respective second polarity output terminal, the first polarity output terminals of the first and second microphone means being connected together and to the first output terminal of said microphone means and the second polarity output terminals of the first and second microphone means being connected together and to the second output terminal of said microphone means.

7. The noise reducing receiver device according to claim 1, further comprising connecting means for rigidly interconnecting said first microphone means and said second microphone means.