Abstract: A squelch circuit and a communication apparatus used with the same able to generate a squelch signal even if a squelch period is short and an operation of a squelch detecting circuit is insufficient, the circuit having: a squelch detecting circuit detecting an existence of a signal on a communication line in response to a transmission signal or a received signal, and generating a first squelch signal; and a squelch control circuit generating a squelch mask signal in response to the first squelch signal and a transmission control signal, and generating a second squelch signal based on the squelch mask signal and the control signal. The first squelch signal is controlled by the transmission signal to generate the second squelch signal in which the lacked portion of the first squelch signal is temporally restructured.

Abstract: A speaker apparatus for vehicle in which a resin terminal plate is mounted on a speaker frame supporting a diaphragm of a speaker unit and at least one network element is mounted on the resin terminal plate. The network element on the resin terminal plate is covered with a resin hood, protecting the network element from water droplets due to dewing and preventing the network element from being contaminated.

Abstract: An outer circumferential portion of a speaker frame on which an edge overlap width portion of an edge portion around the outer circumference of a diaphragm has a taper portion overhanging obliquely forward from the speaker attaching opening diameter d1, an edge attachment portion extending from the outer circumference of the taper portion in a direction orthogonal to a central axis of the speaker, and a mounting plate contact portion extending from the outer circumference of the edge attachment portion to the speaker mounting plate, with a distal end contacting the speaker mounting plate. A resin packing carrying the edge overlap width portion with the edge attachment portion is provided.

Abstract: A cross-sectionally substantially-semicircular portion of an edge portion adapted to connect an outer periphery of a diaphragm to a speaker frame is configured to have an uneven-thickness structure in which the thickness of the portion gradually decreases toward a sticking portion of an outer peripheral portion of the speaker frame from a sticking portion of the outer periphery of the diaphragm. Thus, the propagation characteristic of vibrations generated on the edge portion is improved. Disturbance is prevented from occurring in an mid-range frequency characteristic due to inverse resonance caused by the edge portion.

Abstract: A method for manufacturing an electroacoustic transducer diaphragm of a multilayered structure which includes a first diaphragm layer made from a synthetic resin material and molded into a predetermined shape through injection molding, and a second diaphragm layer laminated in close contact with the first diaphragm layer and made from a material differing from that of the first diaphragm layer, the method includes inserting the second diaphragm layer into a mold for injection molding, and forming the first diaphragm layer integrally with the second diaphragm layer by injection foam-molding within the injection mold.

Abstract: A method for manufacturing an electroacoustic transducer diaphragm of a multilayered structure which includes a first diaphragm layer made from a synthetic resin material and molded into a predetermined shape through injection molding, and a second diaphragm layer laminated in close contact with the first diaphragm layer and made from a material differing from that of the first diaphragm layer, the method includes inserting the second diaphragm layer into a mold for injection molding, the second diaphragm layer being made of not-yet-molded woven fabric or woven fabric molded previously into a predetermined shape of a diaphragm, and injecting the synthetic resin material which is to be molded into the first diaphragm layer into the mold for injection molding, thereby forming the first diaphragm layer integrally with the second diaphragm layer.

Abstract: A method for manufacturing a diaphragm for use in an electroacoustic transducer in a multi-layer structure which includes a first diaphragm layer of synthetic resin molded in a predetermined shape by injection molding and a second diaphragm layer layered in intimate contact on the first diaphragm layer and made of substance different from the first diaphragm layer, includes executing successively a pre-molding step and an injection-molding step, thereby providing the multi-layer structure. The pre-molding step includes attaching a non-molded sheet-like material which is a raw material of the second diaphragm layer to a mating surface of one of the die part of an injection molding die, and closing thereafter the injection molding die to give the sheet-like material a predetermined diaphragm shape. The injection molding step includes injecting synthetic resin material constituting the first diaphragm layer into the injection molding die thus closed thereby to form the first diaphragm layer.

Abstract: A speaker apparatus including a diaphragm; a damper which elastically supports the diaphragm at a damper mount portion; and a frame to which the diaphragm and the damper are attached, wherein the frame has at least one aperture on a back side in a sound emitting direction with respect to the damper mount portion.

Abstract: A speaker apparatus including a diaphragm for emitting sound; and a frame for holding the diaphragm, wherein the diaphragm has a bent portion along inner periphery of the frame.

Abstract: The present invention provides a unidirectional condenser microphone unit that can suppress the occurrence of howling. In a unidirectional condenser microphone unit, a diaphragm 20 extended across a support ring 21 and a backplate 30 supported by an insulation cylinder 50 are arranged opposite each other via a spacer ring 40. A backside air chamber 31 is provided between the backplate 30 and the insulation cylinder 50. When the density of air is defined as ?, sound velocity is defined as c, the effective vibration area of the diaphragm 20 is defined as S, and the volume of the backside air chamber 31 is defined as V, a stiffness s1 of the backside air chamber expressed by (?×c2×S2)/V is increased on the basis of the volume V of the backside air chamber to shift a resonance frequency of a unidirectional component contained in unidirectivity up to a frequency near a high-frequency reproduction limit.

Abstract: A speaker diaphragm that has a high heat-radiation efficiency. The speaker diaphragm includes a diaphragm main body made from a resin, and a metallic plate adhered to a major acoustic surface of the diaphragm main body adjacent a voice coil bobbin. The voice coil bobbin is attached to the diaphragm man body.

Abstract: An electret microphone comprises a back plate having a stationary back electrode and secured to a substrate. An electret layer is formed on the stationary back electrode and a spacer is mounted on the back plate. A diaphragm electrode is mounted on the spacer.

Abstract: A speaker diaphragm outputting a voice with vibrations of a voice coil, includes a base substance and a polyethylene naphthalate fiber sheet laminated on the base substance. The polyethylene naphthalate fiber sheet includes a polyethylene naphthalate fiber impregnated with a resin and is formed like a sheet.

Abstract: There is provided an electrically conductive damper device for a speaker in which local bending is reduced and break-downs of material of the damper and metallic wires incorporated in the damper are prevented, by additionally providing one or more sheets of damper fabric as a reinforcing damper 142 and by bonding it to a main damper 141 by way of various kinds of resin, in order to reinforce a neck portion of the electrically conductive damper. Further, properties of the damper can be adjusted by varying an outer diameter of the reinforcing damper 142, or by selecting the resin to be employed as an adhesive.

Abstract: A speaker surround is provided with a roll part with the curved central part, installed along the periphery of a cone-shaped speaker cone paper (diaphragm), a plane part to fix it to a frame, a junction part to join it to the speaker cone paper (diaphragm), and a reinforcing member installed inside the speaker surround. The reinforcing member is a mesh member installed inside the speaker surround and deforms easily according to the displacement of the speaker cone paper (diaphragm), however it has a structure and an arrangement with no expansion and contraction upon deforming. The mesh article is sandwiched between materials such as urethane foam and integrated by for example heat molding. As material of the reinforcing member, aromatic polyamide fiber, cotton, polyester fiber, olefin fiber, nylon fiber and the like are mentioned, which are formed in mesh by plain weaving, honeycomb weaving, triaxial weaving or the like.

Abstract: A back plate having a recess in an underside thereof and a stationary back electrode at a central portion thereof is secured to a substrate, a spacer having an opening is mounted on the back plate so as to form a vacancy between an inside wall of the opening and a periphery of the stationary back electrode. A diaphragm electrode is provided on the spacer. The back plate has vents in the vacancy so as to communicate a space between the back electrode and the diaphragm electrode to a space in the recess of the back plate.

Abstract: A back plate having a recess in an underside thereof and a stationary back electrode at a central portion thereof is secured to a substrate, a spacer having an opening is mounted on the back plate so as to form a vacancy between an inside wall of the opening and a periphery of the stationary back electrode. A diaphragm electrode is provided on the spacer. The back plate has vents in the vacancy so as to communicate a space between the back electrode and the diaphragm electrode to a space in the recess of the back plate.

Abstract: An electret microphone comprises a back plate having a stationary back electrode and secured to a substrate. An electret layer is formed on the stationary back electrode and a spacer is mounted on the back plate. A diaphragm electrode is mounted on the spacer.

Abstract: There is provided an electrically conductive damper device for a speaker in which local bending is reduced and break-downs of material of the damper and metallic wires incorporated in the damper are prevented, by additionally providing one or more sheets of damper fabric as a reinforcing damper 142 and by bonding it to a main damper 141 by way of various kinds of resin, in order to reinforce a neck portion of the electrically conductive damper. Further, properties of the damper can be adjusted by varying an outer diameter of the reinforcing damper 142, or by selecting the resin to be employed as an adhesive.

Abstract: The present invention relates to a speaker that has a reduced number of parts and effectively emits heat of a voice coil to the outside of the speaker. The speaker includes a diaphragm, a bobbin connected to the diaphragm, a voice coil supported by the bobbin, a center cap for covering an end of the bobbin, and a magnetic circuit for applying a magnetic field to the voice coil. The bobbin and center cap are integrally fabricated.