Abstract: A hearing aid with a microphone, with at least one amplifier fed with the signals from said microphone, whereby the amplifier cooperates with a filter of a higher order for influencing the frequency response, and with a loudspeaker which transforms the amplified signals into soundwaves. This filter (3) can be arranged in the conventional manner between two amplification stages or in the feedback loop of the amplifier (6). In order to allow the optimal adjustment of the frequency response to the respective requirements it is provided in this hearing aid that the filter (3) is arranged as a multiple filter with a biquadratic structure and comprises at least two integrators and an inverting amplifier, whereby the active elements of their components are formed by transistors, preferably single transistors (T1, T2, T3). The feedback loop of the amplifier (6) is guided through an adjustable potentiometer (R.sub.

Abstract: In a close talking microphone device in use for a communication apparatus for a motorcycle, a front casing 2 and a back casing 3 are provided with a front opening 7 and a back opening respectively. Elastic supporting members 5, 6 and 15 for a microphone 4 are accommodated through a first and second filters 11 and 12 between the front casing 2 and the back casing 3 and formed thereon with first, second and third through holes 13, 14 and 16 connected to each other. The microphone 4 is engaged within the third through hole to form a pair of sound paths at each front and back side of the microphone 4. The front sound path is smaller in volume than the back sound path and the opening size of the through hole 13 is defined narrower than that of the through hole 14, whereby a sideward noise diverges into two courses "a" and "b" and the diverging noises reaching the microphone are cancelled by each other so as to be dampened.

Abstract: An apparatus to effect coverage of a hearing aid housing received within a cavity of the sock housing to effect filtration of various airborne contaminants. A modification of the invention includes hair filaments arranged and mounted to the sock structure to effect coverage of the sock member and its camouflage.

Abstract: A dual mode cellular radio communication apparatus includes an echo canceller which cancels echo signals caused by acoustic coupling between a hands-free microphone and a loudspeaker in both analog mode and digital modes. An analog-to-digital converter and digital-to-analog converter may be used both in an analog mode and in a digital mode. A second analog-to-digital converter and a second digital-to-analog converter may be selectively used in the analog or digital mode. The echo canceller may be rendered inoperative during hand-set operation. In addition, a bypass circuit may be provided between an input and an output of the echo canceller so that the echo canceller is bypassed.

Abstract: A pay telephone message system is disclosed that includes a voice message system storing and forwarding to a destination telephone a voice message left by a user. Call information including the destination telephone number is routed out-of-band, that is, in a data or service request channel separate from the voice channel, over a packet concentrator network separate from the voice telephone network. During operation a message telephone call is placed to the voice message system over the existing telephone network. The call information is routed over the concentrator network as a voice message service request. The voice message system returns a token, a call identifier or service request number, corresponding to the service request to the pay telephone interface making the request and handling the pay telephone call. The interface sends the token in-band over the telephone network to the voice message system prior to allowing the pay telephone user to store a message.

Abstract: A base station controller (BSC) personal communications network (PCN), which can for example be based on GSM, has associated with it a local PSTN network and is such that local calls between mobile subscribers and the local PSTN network can be made without involving a remote mobile-services switching centers (MSC), thereby permitting a cheap local call tariff to be employed whilst preserving the interfaces e.g. the GSM Abis and A interfaces. The BSC is intelligent and includes a BSC function, a local MSC function and a location register which slaves mobile subscriber location information from the MSC location registers.

Abstract: A facsimile apparatus having an automatic facsimile/telephone switching function, comprises detecting unit for detecting a high layer compatibility included in a setup message of an ISDN and control unit for immediately connecting the facsimile apparatus to a distant station when the high layer compatibility is indicating a facsimile apparatus. Thereby, in the case where the high layer compatibility is FAX, the FAX is immediately connected to the telephone line. Hence, the waste of time and wasteful bell sound can be eliminated.

Abstract: A loudspeaker system includes a housing (1) having therein at least one loudspeaker (3) which divides the volume of the housing into two parts (V.sub.1, V.sub.2). The first volume (V.sub.1) is coupled, via an aperture in the housing (1), to an acoustic tube (5) which includes a damping element (6). The first volume part (V.sub.1) has a smaller volume than the second volume part (V.sub.2). The damping element is in the form of a Helmholtz resonator.

Abstract: A method and system for enhanced data transmission within a cellular telephone system having multiple assigned voice channels separated by adjacent buffer voice channels. A data processing terminal is utilized to divide the data stream into multiple relatively short data packets which are then sequentially transmitted within alternate adjacent buffer voice channels. By switching from one adjacent buffer voice channel to a subsequent adjacent buffer voice channel, in a predetermined and repetitive order, as each data packet is transmitted, the amount of interference experienced in any one assigned voice channel is minimized. Synchronization between adjacent data packets may be achieved by either utilizing adjacent buffer voice channels in a predetermined and repetitive order or by concatenating an indication of the next buffer voice channel utilized with each data packet. A synchronization packet may also be included with each data packet to permit synchronization between adjacent data packets at the receiver.

Abstract: An AM stereo input signal is processed by an envelope detector, an in-phase detector and a quadrature phase detector to yield outputs which may carry short noise impulses. Each output is low pass filtered to derive an average signal level and each output is ratiometrically compared to the corresponding average to detect a tic or modulation substantially above the average. In response to a tic a hold circuit generates a flag for a period which depends on the quality of the input signal. A dual mode deemphasis and sample/hold circuit normally filters the audio signal in each channel and is effective for the duration of the flag to hold the existing signal in the circuit to blank out the noise impulse.

Abstract: A method and means of automatically accessing several types of radio systems is described. The present invention allows a subscriber unit, which is normally operative in a operator selected radio system, to establish communication with an alternate system if a operator selected system cannot be found. The alternate system may be a conventional single channel mobile relay system or trunked radio system in which the subscriber is authorized to operate. Once communications are established with an alternate communication system, the present invention will periodically attempt to establish communication with the operator selected system while simultaneously attempting to be assigned a higher priority channel in the alternate communication systems according to a priority scan list. Further, the present invention will automatically ignore certain channels which are dedicated for car-to-car use.

Abstract: A device for providing an orderly shut-down of a system of interconnected traffic lights upon loss of its primary electrical power is disclosed. A device for permitting consistent reapplication of power to a line conditioner having a ferroresonant transformer is also disclosed. Further, a battery charger for charging a battery system including a plurality of battery cells coupled in series is disclosed. Additionally, a device for determining proper operation of a power transistor by monitoring its saturation voltage and emitter current is also disclosed. Finally, a device for generating a first alternating signal in-phase with a separately generated second alternating signal is disclosed.

Abstract: A dual mode cellular cordless portable radiotelephone preferentially selects the cordless base station over the cellular system when in range of the cordless base station. When the cordless cellular portable is operating in the cellular mode, the radio channel associated with the cordless base station is sampled for a predetermined time. When a signal on the sampled cordless base station channel is detected, the cordless portable moves to the cordless mode and remains in the cordless mode for as long as the signal quality of the signal on the cordless base station channel exceeds a predetermined value.

Abstract: A contact transducer assembly for an electromagnetically driven hearing device such as a hearing aid or other audio signal reproducing device worn by a user is described. The contact transducer assembly includes a transducer which is attached to a biocompatible support. This assembly is supported on the tympanic membrane of the wearer by surface adhesion, such that it can be readily inserted and removed in a manner similar to that of a conventional contact lens worn on the eye.

Abstract: A curved apparatus which remains stable when placed on a substantially flat surface is shown which has a base portion with an arcuately shaped back surface capable of resting on the substantially flat surface, a hinge rotatably fixed to the base portion, and a cover secured to the hinge and rotatable therewith, to prevent rocking of the base portion when the base portion's front surface is touched while the base portion is resting on the substantially flat surface. Other devices and systems are also disclosed.

Abstract: An annunciator for indicating the removal of an electrical plug from an electrical receptacle. The electrical receptacle includes neutral switching contacts actuated in response to the insertion of a plug into the receptacle. An input circuit in the annunciator apparatus monitors the state of the neutral switching contacts and couples signals produced when a plug is removed to a latching circuit thereby to produce an audible or electrical indication of plug removal. The annunciator circuit does not provide an alarm in response to the insertion of a plug or to an absence of a plug.

Abstract: A diaphragm for microphones having a laminate structure which imparts damping characteristics to the diaphragm is disclosed. The laminate comprises upper and lower resilient layers composed of a plastic film. The upper and lower layers constrain a center layer composed of an elastomeric material having a high dissipation of vibratory shear motion. Manufacturing techniques for making such diaphragms are disclosed.

Abstract: A public telephone network to portable telephone interconnection device (20) is provided. At least one transceiver (30a-n) interconnects a plurality of portable telephones (12) to the public telephone network (16). A channel monitor (38) monitors the transceivers (30a-n and 82) to provide information. At least one information transceiver (82) interconnects the plurality of portable telephones (12) to and is responsive to the monitor (38) for transmitting (104) the information to the plurality of portable telephones (12).

Abstract: A cellular mobile station is operable in a telephone mode and a time data display mode. During the time display mode, the station constantly receives an area identifying code transmitted from a cellular mobile communications system. On crossing a boundary between adjoining cell-site areas, a time difference value is entered from a keypad into a location of a memory corresponding to the received code. This process is continued on a learning basis to store as many time difference values into the memory as there are cell-site areas along the route of a journey. Following the learning process, the station constantly receives an area identifying code and recalls one of the stored time difference data from the memory corresponding to a code received on crossing a boundary and modifies displayed timepiece data with the recalled time difference.

Abstract: A hearing aid includes a filter in an electrical feedback path, the characteristics of which filter are calculated to model acoustic coupling between the receiver and microphone of the aid. A limiter is inserted in the main electrical pathway between the microphone and the receiver to provide stability in the presence of sudden sound bursts. A noise signal is injected continuously into the electrical circuit and is used to adapt the characteristics of the filter to accommodate changes in the acoustic coupling. The level of the noise signal can be varied to match changes in residual signal level to maintain signal to noise ratio and to optimize rate of adaption commensurate with satisfactory hearing function while the noise itself is unobtrusive to the user.