Abstract: A condenser microphone has a conductive diaphragm 3 having an earth electrode layer 31 formed of a conductive light metal; a conductor fixed electrode 5 arranged opposite to the conductive diaphragm 3 through an air layer; an organic dielectric layer 32 formed of the organic compound provided on the boundary surface 32C side between the air layer and the conductive diaphragm 3; and a permanent electric charge layer 32A composed of ions or electrons formed in the inner portion side receding from the air layer 8 side, from a middle position in the thickness direction of the organic dielectric layer 32 in the inside of the organic dielectric layer 32.

Abstract: A condenser microphone has a conductive diaphragm 3 having an earth electrode layer 31 formed of a conductive light metal; a conductor fixed electrode 5 arranged opposite to the conductive diaphragm 3 through an air layer; an organic dielectric layer 32 formed of the organic compound provided on the boundary surface 32C side between the air layer and the conductive diaphragm 3; and a permanent electric charge layer 32A composed of ions or electrons formed in the inner portion side receding from the air layer 8side, from a middle position in the thickness direction of the organic dielectric layer 32 in the inside of the organic dielectric layer 32.

Abstract: 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.

Abstract: An acoustic pulse in size corresponding to the digit position of a digital signal pulse is generated by means of condenser speakers 261, 262, . . . 26n, 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 24 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.

Abstract: 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.

Abstract: 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.