Abstract: A microphone output transmission circuit for a capactive microphone such as an electret microphone employs a differential amplifier to provide a transformerless balanced connection to a microphone transmission line, either at the transmission end or at the reception end thereof. Power is applied in a phantom connection by superimposing a DC voltage on two balanced signal conductors of the transmission line, and using the shield thereof as a ground return line. A pair of microphones with oppositely-directed sound-gathering planes can be connected to respective inputs of a differential amplifier at the transmission end, so that the two microphones together have a bidirectional characteristic.

Abstract: A circuit for interfacing a subscriber loop to subscriber terminal apparatus is provided with a transformer having a split primary winding, a secondary winding and a balance winding. A constant current source is connected to the balance winding to cause a predetermined amount of current to flow therethrough. A current sink circuit is connected serially with the primary winding for regulating the direct current flowing therethrough to an amount proportional to that flowing through the balance winding whereby the DC flux generated by the current flowing through the primary winding substantially cancels the DC flux generated by the current flowing through the balance winding.

Abstract: A television/telephone loudspeaker system is disclosed wherein feedback oscillation caused by having a speaker phone system simultaneously in the transmit and receive mode is minimized. Improved separation of transmit and receive signals is accomplished by microprocessor-controlled dynamic balancing of a bridge network coupled to a telephone isolation transformer to which the incoming and outgoing calls are provided. In addition, by microprocessor sampling of the television receiver's loudspeaker drive voltage from the telephone input line, dynamic proportional attenuation of microphone gain (AGC) is digitally accomplished in simulating full duplex operation. Bridge balancing is accomplished by means of test signals output by the microprocessor during quiet periods with various other audio signal refinements, such as room background noise cancellation, available with the constant monitoring of the microphone signal.

Abstract: Disclosed is a portable tape reader characterized in that a lid provided with a handle is integrally formed on the upper portion of a body provided with a reading head, the body is contained in a container box so that the body can be drawn out upwardly, and when the body is drawn out, the container box is held in the lower portion of the body and an opening of the container box is located below the reading head. In the portable tape reader having the above-mentioned structure, a tape which has been read is securely received and stored in the container box.

Abstract: A moving coil transducer such as a loudspeaker has its coil formed of multiple strand or litz wire. The structure includes a form having multiple turns of the stranded wire thereon, and the leads or ends of the stranded wire forming the coil extend continuously from the moving coil structure to attachment or terminal means carried on some portion of a fixed structure associated with the moving coil. The multiple strand wire is twisted to a predetermined lay throughout its length.

Abstract: The ribbon-type loudspeaker that has the characteristics of large cooling effect such that electrical input power is increased. The ribbon-type loudspeaker comprises magnet means having plates positioned in facing relation to each other to form a gap therebetween; an electrically conductive diaphragm extended between said plates to complete a magnetic circuit, said diaphragm forming an electric circuit transversely of said magnetic circuit, at least one side of said diaphragm being formed with an electrically insulating layer; and a heat absorbing plate extended between said plates and attached in contacting relation thereto over an extended area, said heat absorbing plate being formed with an electrically insulating layer in facing relation to the electrically insulating layer of the diaphragm.

Abstract: The invention relates to a structural member made from a metallic material aving an upper surface exposed to dangers of electric charge accumulations during operation in an apparatus such as a high vacuum apparatus operating with a charge carrying beam wherein the upper surface is formed with a conductive or semiconductive compound of the metallic material which is also present in the body of the structural member and is in electrical contact with the body of the structural member, thereby preventing undesirable charge accumulation on the surface.

Abstract: A multiband analog audio processor is described which provides low peak-to-r.m.s. ratios. A distributed crossover configuration is described which, in the presently preferred embodiment, employs bandpass filters with embedded clippers for high frequency processing. Circuits for improved distortion performance of the distributed crossover configuration is also described. An economical series/parallel crossover configuration with favorable summation properties is also set forth.

Abstract: A variable directivity microphone device comprises a microphone unit assembly provided and arranged with at least three microphone units, wherein the three microphone units are mutually separated by predetermined distances, and front faces of a first and second microphone units of the three microphone units are provided and arranged facing the front surface of the microphone unit assembly while the front face of a third microphone unit is provided and arranged in a direction opposite to those of the first and second microphone units, a first and second variable resistors respectively having a terminal at one end, an intermediate terminal, and a terminal at the other end, wherein respective sliders are mutually linked or ganged and movable between a first, second, and third positions corresponding to the terminals, where the first variable resistor has the terminals at both ends thereof respectively connected to the output sides of the second and third microphone units and the intermediate terminal thereof con

Abstract: A unidirectional dynamic microphone provided with a first sound path to the forward side of the diaphragm and a second sound path to the rear side of the diaphragm in which the second sound path has a chamber coupled to a second chamber associated with the diaphragm through a distributed acoustic RC damping assembly.

Abstract: A superminiature microphone device includes a hollow body in the form of a decorative clothing accessory, a microphone unit including lead wires within the body, and a plug connected by the lead wires to the microphone unit wherein the plug has at least one pin-shaped terminal. A cord connector including a conical collet chuck is arranged to receive the pin-shaped terminal of the microphone unit plug from behind an article of clothing such as a necktie. A clamp member is arranged around the tip portion of the chuck for clamping the chuck about the plug terminal in response to a spring force. Accordingly, an electric cord can be routed from the connector behind the article of clothing so as to connect the microphone unit with an outside device so that the wearer's appearance is not affected by the presence of the connection cord.

Abstract: In an electro-acoustic transducer in a loud speaker and like devices, a diaphragm and/or a voice coil bobbin is or are formed by a composite material consisting of a foamed resin containing reinforcing fibers. Such diaphragm has a large Young's modulus-to-density ratio E/.rho., a large internal loss tan.delta. and a large flexural rigidity E.I, and thus it exhibits good characteristics in sound reproducing. Such voice coil bobbin which is an electric insulator can have a small thickness and is light in weight and has a large mechanical strength, and thus it is free from adversely affecting the vibration of the diaphragm, and accordingly, the sound reproduced.

Abstract: An electromechanical magnetic transducer with a moving armature that is adjustable relative to the working gap. The armature comprises an armature leg, crosspiece, and yoke arms, the adjustment being accomplished by inelastic distortion of the yoke arms. Substantially translational movement of the intrinsic position of the armature leg during adjustment is achieved by providing in each yoke arm one or more struts that undergo S-shaped distortion upon application of adjusting forces in appropriate directions. The structures are further adaptable for rotational adjustments of the armature leg in the gap.

Abstract: A capacitance-type electrostatic transducer is provided that can be operated in an environment where it may be subjected to excessive mechanical vibrations. Unwanted gain variations and/or spurious electrical signals produced by said transducer when operated in such an environment are precluded by preventing relative movement between the spring that urges the backplate into cooperative engagement with the vibratile diaphragm of the transducer and said transducer backplate, at the point of contact between said spring and said backplate.

Abstract: A developing apparatus for developing an electrostatic image on an electrostatic image bearing member. The apparatus is provided with a container for storing toner which is a single component developer. A developing brush roller having fur on its peripheral surface transports the toner from the container and applies it to the electrostatic latent image. The developing brush roller is constructed of a core formed with elastic material and a fur formed on the peripheral surface of the core which contacts the surface of the electrostatic image bearing member.

Abstract: First ends of first and second band pieces with a shape of a circular arc are rotatably connected with each other such that the angle formed therebetween is prevented from exceeding a predetermined angle. End pieces are slidably mounted respectively on the other ends of the first and second band pieces along the direction of extension thereof and receivers of the headphone are mounted on the respective ends of the end pieces.

Abstract: A controllable, alternative annunciator for connection to a subscriber's telephone line 14 (the regular telephone ringer being turned off or disconnected) for providing subscriber-controllable annunciation. When not set for a specific function, the annunciator provides a group of chimes (36) in response to each incoming ring signal. The annunciator can be set to be silent under certain electronically, predetermined conditions. Specifically it provides the following controlled functions: (a) non-chiming for selected intervals (24), (b) chiming only after the first three ring signals (26L), (so that a secretary can answer a normally ringing extension before an executive hears any chime), (c) non-chiming after the first ring signal (26R) (to prevent repetitive ringing signals which might disturb a sleeper), (d) chiming only after a caller rings according to a predetermined code (28) (to prevent chiming from unwanted callers).

Abstract: A radio paging system calls a paged receiver from a first telephone, with signals sent by way of a paging terminal. Paging is carried out by the steps of (a) sending a paging signal assigned to the paging receiver and a message from the first telephone set to the paging terminal; (b) transmitting the paging signal from the paging terminal to the paging receiver via a radio frequency; (c) storing the message at the paging terminal; (d) at the paging receiver, receiving the paging signal transmitted by the step (b); (e) storing in advance the paging number for the paging receiver at the paging receiver; (f) sending tones from the paging receiver corresponding to the paging number stored by the step (e), the tones being sent to the paging terminal by way of a second telephone; and (g) sending the message stored by the step (c) to the second telephone, in response to the tones.

Abstract: Two wire phone exchange system which provides signalling, intercom and paging functions. The system monitors and detects either a dual tone multi-frequency tone or a single tone generated on the line at the local telephone, activates a relay and places a calling party on hold and connects music to the incoming line. A party on hold is reconnected to the answering telephone by depressing a tone signal generating key button. There is an audible warning tone reminder for calls placed on hold which are not picked up after some desired time. The system also provides in-house intercom and paging functions and a release from these functions. When several local telephone instruments are connected on the same line, this system allows the recipient of a call to receive the call at any of the telephones by depressing a tone generating key button.

Abstract: A programmable data storage element includes a self-nucleating bi-stable magnetizable wire and a body of permanently magnetizable material such as barium ferrite. The bi-stable magnetic wire is normally readable in a magnetic reader constructed to cause state reversal of the magnetic wire to induce an output pulse in a sensing coil. The body of permanently magnetizable material can be selectively magnetized in the vicinity of the bi-stable magnetic wire to inhibit reading of the wire in the reader. A given wire can thus be programmed to store a binary bit of data by being selectively enabled or disabled for reading in a suitable magnetic reader. An improved passcard may be constructed by including an insert of barium ferrite in a passcard on which are disposed a plurality of bi-stable magnetic wires in a predetermined pattern. The passcard may be encoded with an identification number or other information at any time subsequent to manufacture by magnetizing selected portions of the barium ferrite insert.