Abstract: A selective call terminal receives selective call information from a message originator. A transmission time is scheduled for the selective call message by a selective call system controller. A plurality of simulcast schedulers coupled to the controller receive and store the selective call message and the transmission time. The simulcast schedulers have an equalization time stored therein, the equalization times for each of the simulcast schedulers calculated by the system controller using simulcast receivers for measuring signal time differences between transmitters. The simulcast schedulers provide the selective call message to corresponding transmitters at a time to transmit the selective call message, the time determined by the transmission time and the equalization time. Transmitter settings and code types defining signalling protocol, data bit rate, carrier frequency and transmitter power, for each message are varied in accordance with information received from the system controller.

Abstract: A base site circuit (38) for operating in a communication system (10) having a plurality of base sites capable of allocating a communication channel for use by a communication unit (16) in response to a communication channel request from the communication unit. The base site circuit includes a receiver (34) that operates in a low sensitivity mode when there are no communication channel requests received, and that operates in a high sensitivity mode which is activated by a control signal. The base site further includes a transmitter (34) which is activated by the control signal and a control circuit (32) coupled to both the receiver and the transmitter, for controlling the receiver and the transmitter. The control circuit (32) provides the control signal to the transmitter and to the receiver, in response to a communication channel request.

Abstract: A radio-frequency receiver employing antenna diversity is provided with a plurality of antennas and a local oscillator. Individual error signals are derived from each of respective ones of signals received from the plurality of antennas. The error signals are thereafter combined in such a way as to arrive at a combined error signal having greater reliability than any one of the individual error signals taken alone. Finally, an automatic frequency control circuit is controlled using the combined error signal. Since the effect of fading on the input signal to the automatic frequency control circuit is reduced, performance of the automatic frequency control circuit is increased and the quality of radio reception is improved.

Abstract: An interactive multimedia system with distributed processing and storage of video picture information and associated data and sound in nodes disposed throughout a cable television distribution system. The nodes are coupled to the feeder cable of the cable distribution system. Each node in the system receives a substantially identical copy of the interactive video picture information and related data from a regional processing center. The users at home televisions associated with a particular node interact directly with the video picture information in that node, rather than with the information stored in the regional processing center or some other remote location, which enables the system to quickly display photographic quality images and complex graphics, as well as sound, at the users' televisions in response to commands received by the users.

Abstract: Method and circuit arrangement for adjusting the volume in a mobile telephone. The telephone comprises a transceiver unit and on the other hand a physically separate operating device. A dc voltage level (DC) corresponding to the desired volume is adjusted with a potentiometer (1) in the operating device and the level is converted with an A/D-converter (2) into a corresponding digital control signal. The control signal is read with a microprocessor (3) in the transceiver unit, which further through the hold circuit (4) controls the gain of the audio amplifier (7). A multiplexer (5) may be provided for controlling and selecting a suitable feedback resistor (6) for the amplifier. The A/D-converter can be located in the operating device or in the transceiver unit. When it is located in the transceiver unit the dc voltage level (DC) is transmitted to the transceiver unit, preferably superimposed on the AC-signal received from the microphone, which then is filtered off before the A/D-converter.

Abstract: The present invention provides a method for checking the degree of coverage in a mobile radio system. According to the method, field strengths are utilized which have been measured from all base stations for all important traffic routes in the mobile radio system. The field strength values are related to geographical coordinates in a respective coverage area and the highest value for each coordinate is stored. The values noted are then compared with a predetermined coverage limit value. With the aid of the method, a graph can be produced using the field strength values stored for each coordinate, the coordinates which are lower or higher than the coverage limit value being marked in the graph.

Abstract: A circuit assembly (400) includes a flexible circuit (402) having first (504) and second layers (502). A current-limiting device such as a nichrome strip (316) is coupled to the flexible circuit (402) for limiting the amount of current during a short circuit condition. A heat sink (404) is selectively placed between the first and second layers of the flexible circuit in thermal proximity to the nichrome wire (316) in order to dissipate some of the heat generated by the nichrome strip (316).

Abstract: A method and apparatus for identifying the channel to which a receiver is tuned includes a controller having a microprocessor, a ROM for storage of programs, a RAM for storage of data and a data storage and communication device; a controlled panel mounted adjacent a light emitting diode (LED) display on the receiver that displays the channel to which the receiver is tuned; and a light detection device mounted in association with the panel. The panel normally is maintained transparent so that the LED display may be readily seen through the panel. In order to determine the number being displayed on the LED display, selected portions of the panel are sequentially rendered transparent while the remaining portions of the panel are maintained opaque. The controller determines which selected portions of the panel have light being transmitted therethrough from the LED display.

Abstract: A method for IF bandwidth switchover and an IF bandwidth switchover apparatus in an AM radio receiver are described. This kind of switchover is appropriate if radio transmitters not only transmit at the normal modulation bandwidth but also broadcast programs with an expanded bandwidth. To obtain optimal reception, the switchover is performed as a function of the reception conditions. To this end, the error rate of supplemental AM information, adjacent-channel interference and the signal strength can be evaluated. These criteria can be used either individually or in various combinations.

Abstract: A squelch circuit (200) having an input is provided including a programmable high pass filter (206) for filtering the input signal to produce a filtered signal. The filtered signal is rectified via a differential rectifier (201) to produce a rectified signal. The squelch circuit (200) also includes a threshold comparator (323) coupled to the differential rectifier (201) for sensing when the rectified signal exceeds a squelch threshold.

Abstract: A radio receiver has a receiver section (103) that receives an information signal and an integrated circuit (105) in which a default operating condition of an electronic device is selectively programmed. A mask option programming link in the integrated circuit (105) is programmed while maintaining electrical isolation of a programming bias from the electronic device (207). The mask option programming link has a first conductor (211) in a first layer with first (212) and second (213) programming contact terminals. A second conductor (210) that determines a default operating condition of the electronic device (207), resides in a second layer that is electrically isolated from the first layer. When sufficient programming bias is applied to the programming terminals of the first conductor (211), energy dissipated by the first conductor eliminates coupling of the second conductor (210) to the electronic device (207), changing its default operating condition.

Abstract: A communication device (100) having a receiver (106) and an audio output device (116) is provided. The communication device (100) includes a digital signal processor DSP (110) for measuring the level of signal energy in a first segment of the frequency spectrum of the received signal to dynamically establish a squelch threshold. The DSP (110) is also used to measure the level of signal energy in a second segment of the frequency spectrum of the received signal. The communication device (100) also includes audio gates (114). The audio gates (114) provides for the unmuting of the audio output device (116) when the signal energy contained in the second segment of the frequency spectrum of the received signal is below the squelch threshold.

Abstract: A method and apparatus for adjusting the power level and spectral content of a digital signal which is transmitted at the same frequency as an audio signal which is modulated via analog modulation method so that the receiver receiving the audio signal is not perceptibly impaired and the power of the digital signal is maximized. The transmission and reception system comprises at least two transmitters for transmitting first and second signals. The first transmitter transmits an audio signal via an analog modulation technique and the second transmitter transmits digital information. A first and second receiver for receiving the two different signals, a power adjustment controller, and processor for adjusting the power of the second digital signal in relation to the first audio frequency range signal at the transmitters. The transmission system transmits the first and second signals to both receivers within a single channel.

Abstract: A communication device (10) comprises a coupler (19) for coupling an external device (30) to the communication device, and controller (16) for controlling the communication device., The controller has at least first and second terminals (22 and 23) for receiving digital numbers from the external device, each digital number representing a mode of operation for the communication device. The controller also includes an apparatus for transmitting a test pulse to the external device, and an apparatus for receiving a response pulse in response to the test pulse. The response pulse has predetermined direction, duration and polarity indicating a mode of operation for the communication device.

Abstract: A communication device (16) comprises first and second transceivers and apparatus for determining when the communication device (16) is in an on-site area (11) and when the communication device (16) is in an off-site area. The first transceiver transmits and receives signals on a first communication medium (17), when the communication device (16) is in a first area (11); whereas, second transceiver transmits and receives signals on a second communication medium (28), when the communication device (16) is in a second area.

Abstract: A communications system provides subfleet calls for both voice and data communications using a secondary identification (301, 303, 305, 307, 309) incorporating a plurality of subfleets in a hierarchical arrangement. A message including the secondary identification (301, 303, 305, 307, 309) is transmitted to a communication unit (117) having a stored secondary identification (301, 303, 305, 307, 309). If the transmitted secondary identification sufficiently matches the stored secondary identification, the communication unit (117) responds to the instructions in the transmitted message.

Abstract: A selective call terminal receives selective call information from a message originator. A transmission time is scheduled for the selective call message by a selective call system controller. A plurality of simulcast schedulers coupled to the controller receive and store the selective call message and the transmission time. The simulcast schedulers have an equalization time stored therein, the equalization times for each of the simulcast schedulers calculated by the system controller using simulcast receivers for measuring signal time differences between transmitters. The simulcast schedulers provide the selective call message to corresponding transmitters at a time to transmit the selective call message, the time determined by the transmission time and the equalization time. Transmitter settings and code types defining signalling protocol, data bit rate, carrier frequency and transmitter power, for each message are varied in accordance with information received from the system controller.

Abstract: A wristworn receiving device suitable for being worn about a wrist comprises a receiver (404) for receiving radio frequency signals on a particular operating frequency, a housing (142) for enclosing the receiver (404), a first wristband section (102) including a first wristband loop antenna portion (118) and a movable clasp member (122), and a second wristband section (104) including a second wristband loop antenna portion (134) terminated in a fixed clasp member (140). The first (118) and second (134) wristband loop antenna portions are partially resonated at the operating frequency. The second wristband loop antenna portion (134) is coupled to the first wristband loop antenna portion (118) and is positioned by the movable clasp member (122) at first (204) and second (202 or 206) positions along the first wristband loop antenna portion (118) so as to form a resonant loop antenna which remains substantially tuned to the operating frequency at the first (204) and second (202 or 206 ) positions.

Abstract: A variable frequency RF passband filter is aligned or calibrated to maximize the sensitivity of a radio receiver using reference frequencies obtained using a fixed frequency oscillator present in a different band tuning section of a multiband receiver. The intermediate frequencies of the various band sections of the multiband receiver are selected whereby a fixed frequency source in one band corresponds to an intermediate frequency employed in the band for which the tunable RF filter is being aligned.

Abstract: A method and apparatus are provided for determining a particular transmitting station from which program signals are received and translated by a monitored receiver within a test area and including mobile receivers. A stored transmitter characteristic table includes a corresponding transmitting station identification stored with a predefined subarea of a plurality of predefined subareas within the test area for each predetermined tuned frequency of the monitored receiver. A tuned frequency of the monitored receiver is identified and the particular transmitting station corresponding to the identified tuned frequency is identified responsive to both the identified tuned frequency of the monitored receiver and the stored transmitter characteristic table. The identified transmitting station data is stored with time of occurrence data.