Abstract: A minimal inductance electrodynamic transducer having ferromagnetic shunting rings coated with a highly conductive material to increase the induced current carrying capacity of the transducer. A plurality of thin shunting rings separated by a non-conductive adhesive, attached to a pole piece connected to a magnet and/or a center pole, allows the device to operate at high power levels without saturation. The shunting rings also allow for sufficient induced current to flow in the magnetic circuit in order to oppose the magnetic field created by the voice coil.

Abstract: An arrangement for increasing the available character spaces for softkey label screen prompts in a small interactive display for use in a telephone terminal is provided. In a first configuration of the arrangement, available character spaces in the interactive display are partitioned into equal adjacent character sets with each character set having an allocated number of character spaces for displaying a softkey label. The telephone terminal is configured such that available character spaces in adjacent character sets are borrowed and used by a particular character set having a softkey label for display that exceeds the allocated number of character spaces in the particular character set. In a second configuration of the arrangement, a first character set is combined with an adjacent second character set for displaying the large softkey label.

Abstract: A system for distributing remote telephone traffic between a base station and remote antenna site is disclosed. The base station and remote antenna sites are connected via a cable television network. The base station receives from a public telephone network parallel channels of outbound voice signals for radio telephones operating within the cellular areas of the remote antenna sites. The base station will digitize and time compress each of these outbound telephone signals, and insert them in a transmit frame. The transmit frame is modulated on a subcarrier and applied to the cable television network. A plurality of remote sites are connected to the cable television network and receive and rebroadcast digitized voice signals to radio telephones operating within their cellular areas. Inbound serial channel data received from a radio telephone is inserted in a serial receive data frame.

Abstract: A utility meter reading and communications system gathers data from utility meters and sends that data to a utility company's central data collection point (host computer) via phone lines. The system places a call on the user's telephone line at a specified time and date and transmits data using dual-tone multifrequency (DTMF) format. The system ensures that users still may use the telephone line by sensing off-hook conditions initiated by a resident's telephone and immediately dropping the line to reestablish dial tone for the residential customer. The system uses a variety of error-detection procedures and communications protocols to ensure a high degree of reliability in communicating data to and from the central office and the utility meter system. The system also uses communications protocols and handshaking to ensure accurate data communication and allow immediate interruptions of communications should the customer attempt to use the telephone line.

Abstract: A distributed antenna system is provided which is formed from a series of modular stages interconnected by cables. Each stage may include an antenna, a filter, a compensating amplifier and preferably elements for impedance matching to connecting cables. Connecting stages also include a coupler for combining the output from the stage antenna with the output from the preceding stage and passing the combined signal to the stage output. Where the stages are part of a transmitting system, the coupler is replaced by or functions as a splitter, an input thereto from, for example, a preceding stage, being applied to the stage antenna and to the stage output.

Abstract: In a radio loudspeaker telephone device (30) having a radio controller (18) which makes a radio transmitter (15, 17) transmit to a radio channel a dial signal representative of a destination subscriber telephone set, the radio controller produces a timing signal representative of a first time instant at which the radio controller receives a response signal through a radio receiver (16, 17) from the radio channel. The response signal indicates that the destination subscriber telephone set is not busy. A detecting circuit (33) produces a ring-back tone detection signal while the detecting circuit detects a ring-back tone signal which is received through the radio receiver from the radio channel and which indicates that the destination subscriber telephone set is called by the telephone device. A switch unit (32) usually connects a microphone (11) to the radio transmitter.

Abstract: A mobile station, operable in a mobil communication system that executes a location registration processing by using the channel quality of a base station and an information concerning a base station the mobile station includes a base station information memory unit for storing therein information concerning a plurality of base stations and an amount in which the channel quality of the base station is changed with time and a location judging unit for judging on the basis of the amount in which the base station information is changed with time and which is stored in the base station information memory unit whether or not location registration processing is to be executed indicating a location in service area.

Abstract: A radio telephone system is comprised of a communication network, a cordless telephone apparatus and a plurality of public radio base stations, both being connected to the communication network, and a handset unit of the cordless telephone apparatus is capable of exchanging messages with the plurality of public radio base stations. The cordless telephone apparatus is provided with a control-data storage unit for storing data of controlling handsets unit belonging to the cordless telephone apparatus. The control-data storage unit stores data each comprising a combination of an extension number and a phone number of a handset unit. The cordless telephone apparatus judges whether a handset unit to be reached is in a service area of the apparatus, when the handset unit is called from another handset unit of the cordless telephone apparatus.

Abstract: In an active circuit which separates and amplifies signals received via an antenna (A) into a higher-frequency FM band and a lower-frequency FM band, weakening of the FM signals by the AM-band amplifier is avoided by adding, to the previously known circuit which has first, second, and third capacitors (C1, C2, C3), a third inductance (L3) between the second (C2) and third (C3) capacitors, and by removing any serial inductance from the adaptor or matching circuit (AP) at the input of the FM amplifier stage (UKW).

Abstract: A communication system includes a number of terminals, each allowing the input of a text message represented as digital symbols, and storing the text message, and including modems for encoding the text message for transmission via a public telecommunications network to a remote terminal, the terminals also being arranged to receive acknowledgements from the remote terminal that such text messages have been received, and to re-attempt transmission in the event of a transmission failure or the absence of such an acknowledgement, and the terminals further being arranged to automatically answer a call placed via the public telecommunications network, to receive and decode a text message from a remote terminal included in such a call, to store the received text message, to transmit a signal acknowledging receipt of the received text message to the remote sending terminal, and to allow retrieval of the stored text message.

Abstract: A cellular radio system comprises a plurality of basic stations each having a radio transceiver serving a cell of the system. A mobile station of the invention has a radio transceiver for communicating with one or other of the base stations, as well as long term averaging units (LTA.sub.0, LTA.sub.1, LTA.sub.N) for time averaging handover criterion (HOC) measurements over a first averaging period. The mobile station also includes a summer (S.sub.N) for applying a first hysteresis margin to the time averaged HOC measurements to provide a first handover indicator. The mobile station also includes short term averaging units (STA.sub.0, STA.sub.1, STA.sub.N) for time averaging HOC measurements over a second averaging period which is relatively short compared to the first averaging period, as well as a summer (S.sub.W) for applying a second hysteresis margin, which is relatively large compared to the first hysteresis margin, to the time averaged HOC measurements to provide a second handover indicator.

Abstract: In a conventional Gilbert-cell active mixer, two local oscillator matched pairs of transistors receive a local oscillator input signal and are coupled to a radio frequency matched pair of transistors which receive a radio frequency input signal. The circuit generates an intermodulated output signal at the collectors of the local oscillator matched pairs. Noise degradation is reduced over the conventional mixer by replacing the standard radio frequency emitter degeneration resistor with a reactive element, thereby reducing thermal noise. Narrow-band input matching is achieved by insertion of a series inductive element and optional parallel capacitive element in line with the radio frequency input. Thermal noise contributed to the circuit is thereby minimized while circuit linearity is preserved in the narrow frequency band of interest.

Abstract: A radiotelephone of this invention comprises a sending-speech level varying circuit for varying the level of the sending-speech signal from the microphone and supplying the resulting signal and receiving-speech level varying means for varying the level of the receiving-speech signal demodulated by receiving means and supplying the resulting signal to the speaker, as well as a talking-mode setting section and a gain control circuit. At the talking-mode setting section, either the handset talking mode or the hand-free talking mode is set. At the gain control circuit, the gains of the sending-speech level varying circuit and receiving-speech level varying circuit undergo variable control according to the talking mode set by the talking-mode setting section. The gain control is carried out in such a manner that the gain becomes a first specific value when the handset talking mode has been set, and a second specific value larger than the first value when the hand-free talking mode has been set.

Abstract: A telephone system includes a data modem that is coupled to a control microprocessor and a Data Access Arrangement (DAA) for detecting a Caller ID. The detected information is used to select a specific action dependent upon the specific Caller ID. Only one relay is needed with no other parts to connect the Caller ID to the data modem. A programmed Intelligent Work Station (IWS) determines whether to respond to the call and the type of response.

Abstract: An RF repeater for interfacing with a base station for exchanging transmit and receive signals in a time division duplex cordless telephone system comprises a multicarrier amplifier having an input and an output and a transfer switch connected to the amplifier output and the amplifier input and having first and second switch states. The switch means connects receive signals from the handset to the amplifier input and the amplifier output to the base station in the first switch state, and connects the base station to the amplifier input and transmit signals from the amplifier output to be broadcast to the handset in the second switch state. The operation of the switch is controlled so that the transmit and receive signals are alternately amplified by the amplifier. Thus, only a single amplifier is required.

Abstract: An image processing device for converting a scanned image into a monochrome image includes a scanner for providing an image signal which is applied to a sampling and holding circuit. The output of the scanning and holding circuit is supplied to a peak hold circuit and to a comparator. The output of the peak hold circuit is also applied to the comparator and the output of the comparator is supplied to a D-type flip flop circuit, the output of which is fed back to the input to the comparator from the scanning and holding circuit. The D-type flip flop generates an alteration of black and white level signals when the output from the sampling and holding circuit is close to the threshold level whereby a printer will print alterations of black and white dots.

Abstract: A microphone power supply for use with precision microphones having an attached pre-amplifier, connects to an analyzer with a coaxial cable and is powered by an ICP current source in the analyzer. The power supply provides a polarization voltage and a pre-amplifier power voltage to a microphone and pre-amplifier assembly. The power supply receives an AC audio signal produced by the microphone, buffers the AC signal, and provides the AC signal to the analyzer through the coaxial cable.

Abstract: An active noise control apparatus comprises a secondary sound source for generating sound canceling noise emitted from a noise source, first and second microphones sequentially arranged between the noise source and the secondary sound source at a predetermined distance in a direction from the noise source to the secondary sound source, a coefficient multiplier for multiplying an output signal of the second microphone by a coefficient corresponding to a ratio of a transfer function of the first microphone with respect to the secondary sound source to that of the second microphone with respect thereto, a subtracter for obtaining a difference between a multiplication resultant signal and an output signal of the first microphone, and a signal processor for outputting a secondary sound signal obtained by multiplying the difference signal with a predetermined coefficient to the secondary sound source.

Abstract: An active noise controller includes a prediction filter which includes a delayer for delaying the noise or error detection signal by a predetermined period of time, a first adaptive filter for processing the output of the delayer to deliver its periodic component, and a subtractor for subtracting the output of the first adaptive filter from the noise detection signal to deliver a random component of the signal. More specifically, the prediction filter is capable of dividing the noise or error detection signal into two, periodic and random, components. In addition, two, second and third, adaptive filters are provided for processing the periodic and random components respectively. Accordingly, the second and third adaptive filters become responsive precisely to their respective periodic and random components regardless of the ratio in level between the two components, whereby any undesired noise consisting of the two discrete components will be suppressed.

Abstract: A data terminal which enables a craft technician to communicate through a gateway processor to other computers includes a program language support library and an operating system which can receive a condensed form applications program and supplement the received program to create a fully executable applications program. This permits convenient downloading into the terminal over a conventional telephone circuit. Also disclosed is an improved interface through which a telephone circuit can be tested to determine if it is active and idle in a substantially non-invasive manner. Respective computer protocols can be entered in the terminal in association with telephone numbers of respective computers for automatic use whenever the respective computer is called. A limited display area of the terminal is controlled so that a larger page of text can be sequentially displayed through it as if the limited display area is scanning across the larger page of text.