Other

Matsushita Electric Industrial Co., Ltd.

Yasuhiro Riko

Yoshinobu Yasuno

Kenzo Miura

A condenser microphone has a conductive diaphragm having an earth electrode layer formed of a conductive light metal; a conductor fixed electrode arranged opposite to the conductive diaphragm through an air layer; an organic dielectric layer formed of the organic compound provided on the boundary surface C side between the air layer and the conductive diaphragm ; and a permanent electric charge layer A composed of ions or electrons formed in the inner portion side receding from the air layer side, from a middle position in the thickness direction of the organic dielectric layer in the inside of the organic dielectric layer

Condenser microphone and production method thereof

A digital electro-acoustic transducer for improving the speech quality of sound under noisy circumstances is disclosed. A plurality of sound generating units A constituted by electrostatic electro-acoustic transducers (condenser earphones) and a sound receiving unit B constituted by an electrostatic acousto-electric transducer (condenser microphone) are disposed in a cavity of a soundproof housing. The units A are provided in a feedback loop and an output level of the unit B is adjusted by an preamplifier. An output of the preamplifier is sampled by a sample-and-hold circuit and an output thereof is delta-modulated by a delta modulation circuit. The number of pulses produced by the circuit is subjected to arithmetic operation in an arithmetic circuit to produce a drive signal for the units A. Vibration of a vibration film of the unit B is detected and arithmetical control is made to be always maintained to zero. On the other hand, an audio signal supplied from a signal terminal is superposed on a drive signal for the units A and is emitted into the cavity.

Digital electro-acoustic transducer

An acoustic pulse in size corresponding to the digit position of a digital signal pulse is generated by means of condenser speakers , that are grouped electro acoustic transducer elements corresponding to each bit that forms a digital signal employed in a communication channel. Then, an electro acoustic D/A converter for synthesizing the pulse in a cavity is composed. Further, this electro acoustic D/A converter is to be as a component, and an electro acoustic A/D converter is composed by additionally providing electric accessories as in the A/D converter comprising a general electric circuit. In this manner, a transmitter/receiver having a function for converting between an acoustic analog signal and a digital electric signal is composed.

Digital telephone transmitter/receiver

A digital type electroacoustic transducer converts between a digital electric signal and an analog acoustic signal and includes units A (sounding bodies) arranged on the same plane as that of units B (sound receiving sensors), with the number of group units being decided at a ratio corresponding to a digit position of each bit of the digital signal. When the bit exists, a power source for electrode driving and the group unit are connected, and both of an electric/acoustic conversion and a digital/analog conversion are simultaneously executed through the unit A. The units B provide an addition value of all outputs of the units A. After a level of the detection acoustic signal is adjusted by a preamplifier, the signal is delta modulated and supplied to an arithmetic operating circuit. When a digital electric signal which is input does not exist, only the acoustic signal which arrives at the diaphragm surface of the unit B is input to the arithmetic operating circuit. A digital signal proportional to the acoustic signal is derived from a digital type electroacoustic transducer output terminal.

Electroacoustic transducer of digital type

An electromagnetic transducer in which a D.C. magnetic flux generating section including a permanent magnet and a signal flux generating section including a coil are arranged in spaced relation on opposite sides of a diaphragm to form a balanced type transducer.

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Yokohama-shi, Kanagawa, Japan

Yasuhiro Riko