Abstract: A mobile cellular communications system and method are disclosed, which limit access of private network cells only to mobile subscribers of those private networks. In cells belonging to the public network, only information about the public cells is broadcast on the public system information control channels. This public cell information is thus the only cell information that the non-subscribers' terminals are able to receive. When a mobile terminal belonging to a subscriber of one or more private networks surfaces in a public cell, the public network transmits a radio link control message to that mobile terminal, which contains information about the candidate cells for selection associated with the private network(s). The private network transmits system information via the private cell to a subscribing mobile terminal about the private and public cells' neighboring cells.

Abstract: At the mobile station the measured pilot energy of each pilot in the candidate set is iteratively compared against a threshold generated in accordance with the sum of the energies of the pilots in the active set. If the strongest pilot in the candidate set satisfies this threshold condition, it is added to the revised active set. A second iterative process is performed to determine whether a pilot should be deleted from the revised active set. The mobile station determines whether a change to the current active set is desirable by measuring the energies of the pilots in the active set and the candidate set, and dynamically adjusting the necessary thresholds based on its own estimation of the communication environment.

Abstract: A dual-band radio monitoring apparatus which provides the reception of transmissions on commercial AM/FM frequency band(s) to be monitored and interrupted by transmission(s) on a controlling VHF/UHF frequency band(s), especially for use by motor vehicle racing fans so that they may have a continual AM/FM reception which is muted for reception of the controlling VHF/UHF transmission of conversation between the race car driver and his pit crew.

Abstract: An improved squelch circuit which utilizes a phase-locked-loop (PLL) arrangement to track the carrier signal and identify when audio communication should be curtailed. The lock detect circuit of the PLL is used for a signal-to-noise monitor. As the loop locks and unlocks, the lock detect line pulses. These pulses are integrated to give a direct current (DC) level. This DC level is proportional to the signal-to-noise ratio of the carrier signal. The signal-to-noise level is monitored by the squelch gate until a threshold is passed. Falling below the threshold results in a squelching of the audio, when the ratio exceeds the threshold, then audio is commenced. The circuit is enhanced by the ability to automatically adjust the threshold level once the PLL has locked onto the signal.

Abstract: A baby monitor system that includes a parent unit and a baby unit that have a two-way radio frequency communications link established therebetween. The baby monitor system also includes a message storage mechanism that allows a care giver to record a soothing message for playback to the baby in response to activation of a play switch. Use of the recorded message allows the care giver to provide the baby with a soothing message even when the care giver is in an ambient noise environment, such as a shower, that could startle are irritate the baby.

Abstract: An antenna device having a surface on which radiation of an output of the antenna device is suppressed in at least one direction is attached to a case so that the radiation-output-suppressed surface of the antenna device is arranged to face an user side at the time of talking.

Abstract: An AGC method and apparatus is provided for a receiver to control the signal power of a received RF signal over a wide dynamic range and significantly reduce the ADC clipping time to a level appropriate for cellular communications. The AGC apparatus comprises an ADC (analog-to-digital converter) for generating digital samples of a received signal, a controller for providing a receiver gain setting based on the digital samples generated and an actuator for applying the receiver gain setting. The controller compares digital samples generated by the ADC to a first predetermined reference level, accumulates an error signal, calculates an attenuation adjustment based on the accumulated error signal and sums the attenuation adjustment with a previously calculated receiver gain setting for providing the actuator with an updated receiver gain setting which is applied therein.

Abstract: A single counter dual modulus frequency divider apparatus (400) utilizes a programmable divider (508) configured to receive an RF input signal at the divider system input (500) and a modulus control (516) produced by a programmable counter (510). The modulus control (516) sets a divide value of the programmable divider (508) to produce a divided signal at a programmable divider output (514). A switch (512) is configured to receive a first program instruction at the first program instruction input (504) and a second program instruction at a second program instruction input (506) to produce a count control (518). The programmable counter (510) receives the divided signal appearing at the programmable divider output (514) and the count control (518). The count control (518) sets the count value of the programmable counter (510).

Abstract: The base station of a wireless communications network determines what features a mobile station will support, then downloads information to the mobile station which will notify the mobile station of which network features are available and how they may be accessed in the local network. Specifically, the base station provides the features codes that are required to access the network features. The base station may also inquire into what features the mobile station supports. Each of these communications may take place over the combination of the Paging Channel/Access Channel, collectively, the Control Channel, or the Traffic Channel. With the downloaded information, the mobile station user may select a desired feature using the method to which he or she is accustomed, i.e., either by selecting a menu location or by entering a familiar sequence of keystrokes. The mobile station's internal processor converts the entered values into the feature codes corresponding to the selected features within the network.

Abstract: A multi-stage mixer circuit has two or more mixer stages, each stage having a mixer core and successive mixer cores being separated by one or more current mirrors. By using current mirrors to process the currents generated by the mixer cores, instead of current-to-voltage and voltage-to-current converters as in the prior art, the present invention provides a mixer circuit with reduced signal distortion and power dissipation. In one embodiment, the two mixer cores of a two-stage mixer circuit are implemented using the same type of transistor devices (e.g., N-type), and there are two current mirrors between the mixer cores. In another embodiment, the two mixer cores of a two-stage mixer circuit are implemented using different types of transistor devices (i.e., one N-type and the other P-type), and there is only one current mirror between the mixer cores.

Abstract: The invention relates to a radio system where oriented antenna beams are used over a radio connection between a network subsystem and a subscriber terminal with a fixed location. The network subsystem comprises means for storing parameters of a bidirectional radio connection, including e.g. the transmit beam angle, the receive beam angle, the air interface delay profile, the air interface impulse response, the transmit power of the network subsystem, the transmit power of the subscriber terminal, and the number of rake branches. The network subsystem also comprises a common measuring unit that measures parameters of a bidirectional test radio connection of a new user.

Abstract: The present invention provides a method and apparatus for restricting operation of a cellular telephone to well delineated geographical areas. The cellular telephone is equipped with a location device for ascertaining the current geographical location of the cellular telephone. The ascertained geographical location is compared with information pertaining to the allowability of operation of cellular telephones in various geographical locations. A determination is made as to whether the cellular telephone is allowed to operate in its current geographical location. The cellular telephone accordingly enables or disables transmitting by the transceiver of the cellular telephone.

Abstract: A radio-frequency filter for a radio apparatus operating on two frequency bands is based on impedance step resonators, wherein two interconnected resonator sections (L2, L1) having different impedances are dimensioned such that the resonator's fundamental resonating frequency (f0) is on the lower operating frequency band and a certain harmonic resonating frequency (fs1) is on the higher operating frequency band. The filter may have separate ports (port 2, port 3) for the signals of the different frequency bands and they can be isolated from each other using additional filtering (LC1, LC2).

Abstract: A system and method for tracing calls, such as those terminating in a wireless telephone system, is disclosed. The system is part of a communication network that uses a switch connected to a caller. The switch extracts information about the caller such as a calling party number and other information useful for tracing the call. Once the information has been extracted, the switch sends the information to a storage device associated with the called party, such as a home location register. The storage device creates a log of the call, storing all the extracted information. When the call is to be traced, a device capable of accessing the storage device can easily retrieve the stored information and thereby identify and locate the caller.

Abstract: A method is provided for placing a call from a two-way radio subscriber unit operating within a two-way radio communication system (100). A user operates the subscriber unit in a call address search mode (310), and provides search criteria data that references a communication target (320). The search criteria data is transmitted in a query to system equipment which provides, in response, a list of matching identifiers and corresponding call addresses (330, 340). This list is presented to the user and a selection obtained (350, 360). A call address corresponding to the user selection is used to initiate the call to the communication target (370).

Abstract: The present invention relates to a radio transceiver having a plurality of switchable antennas. The radio transceiver comprises (1) a housing, (2) a dipole antenna installed on the housing for transmitting and receiving radio signals, (3) at least one patch antenna installed on the housing for transmitting and receiving radio signals, each patch antenna being connected to an antenna switch, (4) an impedance matching circuit connected to the dipole antenna and each said antenna switch, (5) a transceiver circuit connected to the impedance matching circuit for converting radio signals received by the antennas into base band signals and converting base band signals to be transmitted into radio signals, (6) and mode control means for controlling each said antenna switch and the impedance matching circuit to match the impedance of the impedance matching circuit with the connected antennas.

Abstract: A method of operating a selective call receiver (170) that roams a plurality of separate simulcast areas (20) including a specific area where the selective call receiver shares the same address with a second selective call receiver but where only one of the receivers is able to decode a message broadcast in the specific area includes the steps at the selective call receiver of receiving a target address, a tag representative of the specific area, and an associated message. Then the associated message is decoded (40) when both the target address and the tag representative of the specific area match an address (38) and a tag (36) stored in a memory location (77 or 76) within the selective call receiver and otherwise ignoring the associated message when either the target address or the tag representative of the specific area fail to match the tag and the address stored.

Abstract: Tone generating apparatus for a cellular telephone simulates those tones normally sensed by a user of a conventional land-line telephone. The cellular telephone is adapted to communicate with a base station via a service provider which provides different types of service, such as HOME service, ROAM service, or alternate HOME service. A progress tone generator is actuable to generate for the user selected dial tone indications as a function of the detected type of service provided by the service provider. In addition, when the keypad of the cellular telephone is operated, digit tones identifying the actuation of the respective keys are generated as is digit data which represents those keys; the digit data being transmitted to the base station to dial a respective telephone number. A warning indication, such as a distinctive tone, is generated in the event that the digit data does not represent a valid telephone number.

Abstract: A communication method is provided in which mobiles operating in a trunk mode operation transmit a message on a direct mode operation channel indicating a trunk mode operation connection is present. If a mobile outside the range of coverage of the trunking system receives the message it will deduce from the message the slot structure of the trunk mode channel and its timing, and will then be able to transmit a request for a direct mode connection on an appropriate slot of the trunk mode channel. Some or all of the mobiles operating in trunk mode will then be able to switch to direct mode to connect with the mobile outside the range of coverage.

Abstract: A method for selecting a digital control channel (DCCH) for a mobile station operating in a cellular system. In the method, after a first DCCH meeting rssi requirements has been located, a search is made for a more preferable second DCCH before camping on the first DCCH. If a more preferred second DCCH is found, the mobile station then camps on the second DCCH. The method includes the process of performing a quick reselection on available digital control channels(DCCH) at points in the selection process, when a first DCCH that meets received signal strength (rssi) criteria at the mobile station has been located using a conventional process, but a more preferable second DCCH could possibly still be found. In an embodiment of the invention the quick reselection may be performed on DCCHs included in a neighbor cell list received on the first DCCH.