Abstract: A support stand for a beverage container is formed from rigid wires and includes a substantially planar support platform supported by two legs that are removably interengaged with and locked with locking loops formed as part of the wire support members.

Abstract: A method of tracking subscribers (201, 203) in a networked radio communications system (100, 200). The subscribers (201,203) are able to roam among a plurality of coverage areas (104-106) which are serviced by a plurality of transmitters (107-109). The transmitters (107-109) are coupled to a central processor (CP, 110), which accesses a memory device (112) for storing subscriber records and site records. Subscriber records include location information for each of the subscribers, while the site records include a logical representation of geographical relationships between the coverage areas. The method relies on the subscriber to send an inbound message (330) which includes its current location. Further, the CP (110) records a message time for the inbound message, producing a timestamped location, then updates (405) a corresponding portion of the subscriber record with the timestamped location.

Abstract: Ceramic block filters can be constructed to have non-symmetrical, i.e. unequal, input and output impedances. These filters can be used to eliminate impedance matching networks in radio communications devices. These impedance matching networks (22, 14) are precluded when the input and/or output of a ceramic block filter (100) is controlled by appropriate selection of the physical parameters of the block to achieve a direct impedance match between an adjacent circuit element and subsequent signal processing stages in the device.

Abstract: The ratio of peak power level to average power level in a power amplifier used in a QAM communication system transmitter can be reduced by preselecting magnitudes and phase angles of complex-valued pilot symbols used in multi-channel, N-level QAM.

Abstract: A ceramic bandpass filter (10) with improved input/output isolation can be surface mounted. Input/output pads (18 and 2) through which electrical signals pass are located on one surface of a block of dielectric material (12) to permit use of the so-called surface mount manufacturing techniques. Slots in the sides of the block that preferably run between the input-output pads can reduce coupling between the input/output pads and permit adjustment of high-side transmission zeroes by changing the dimensions of the slots. No wired connections to the ceramic bandpass filter block are required.

Abstract: An impulse transducer that does not use eccentric, motor-driven weights is constructed of a permanent magnet movable armature that oscillates within a housing and impacts resilient bumpers to produce vibrations. The armature is accelerated by a varying magnetic field energized by an alternating current. The dimensions of the enclosed housing and the mass of the movable armature as well as the strength of the magnetic fields can be optimized for the impulse magnitude that is desired.

Abstract: A two-pole monolithic piezoelectric filter (50) provides an improved frequency response at specified frequencies above the center frequency of a two-pole filter; at these frequencies the frequency response exceeds the attenuation of a four-pole filter without any increase in space, volume, or cost by the inclusion of additional resonator stages (64 and 68) formed into the substrate (52). Appropriate selection of the dimensions of these resonator stages can be used to adjust the frequency at which these resonator stages provide additional desired attenuation.

Abstract: A test device (101) for use in a trunked radio system (102) employs a received signal strength indicator (RSSI) detector (120) to analyze transmission parameters. The test device (101 ) includes a transceiver (118) for transmitting and receiving radio signals, and a channel controller (116). The test device further includes memory (117) for storing (403) data, and test control means (116) for causing the transceiver to receive (303, 406) outbound signals on active communication channels. The test device (101) then processes (303-305, 402-404) the power levels for the outbound signals, and either re-transmits (305, 307) the results, or stores (407) them in memory.

Abstract: In a QAM communications system, a novel synchronizing sequence of symbols added to the information channel simplifies acquisition of timing and synchronization by a receiver. Such synchronization vectors provide signals for improved AFC control signal generation.

Abstract: A ceramic bandpass filter (10) that has transmission zeroes above the passband is accomplished without using the top patterning by a block structure that includes a localized mesa (26) formed at the top end of the block that provides increased capacitive coupling between the open circuits and the resonators (30, 32, and 34). This increased top end capacitance provided by the mesa (26) can provide high end or high side transmission zeroes to the characteristic transfer function of the filter.

Abstract: A method is disclosed which automatically establishes a communication path between at least two devices (106, 110, 118, 120, 128). Each device has a unique identification (ID), and is coupled to a switching center (132-137) of a Public Switched Telephone Network (PSTN, 130). The PSTN (130) has a facility access center (FAC, 140) for coupling the switching centers (132-137) to a storage facility controller (SFC, 146), which provides access to a central storage facility (148). The method includes the steps of determining (306) an ID of a first device and then selecting (318) a portion of the central storage facility (148) associated with that ID. Then, after ascertaining a second ID of a second device, an element associated with the second ID is retrieved (322) from that portion of the central storage facility (148). Lastly, a communication path is created (327, 328) between the first device (106, 110, 118) and the second device (108, 112, 128).

Abstract: An IF crystal filter for a VHF receiver including:a crystal filter (18) having an input (22) and an output (24)a reactive impedance means (26) coupled across the crystal filter input and output for changing the selectivity characteristics of the crystal filter by a predetermined amount; andswitching means (32) having a control input responsive to a control voltage, and coupled to said reactive impedance means for selectively shunting the reactive impedance means to ground, whereby to change the selectivity of the filter.

Abstract: A method of collapsing a communication path among at least two communication units (104-107) reduces the number of sites normally required to provide a communication. Each of a plurality of site controllers (103) in a radio communications system has a corresponding coverage area (100, 101), and at least some of the coverage areas (710-712) overlap one another. The method includes the step of determining (402) whether the communication units are currently being serviced by different sites, and then determining (405) whether they can be serviced by a common site. When the communication units are serviceable by a common site, the call might be established (406) through the common site, resulting in a reduced number of sites required to complete a call.

Abstract: A shielding apparatus for use with a non-conductive package has an insulated lid (102) which is retained in contact with a substrate (104) for holding an electrical circuit. The shielding apparatus includes a first conductive flash (201) deposited on the interior surface of the insulated lid (102), to produce a substantially contiguous conduction layer, and a second conductive flash (203) deposited over a film (110) disposed on the edge of the insulated lid (102), to produce a partially contiguous conduction layer. The shielding apparatus also includes a layer (108) for affixing the insulated lid (102) to the substrate (104), to produce an enclosure for isolating the electrical circuit from extraneous radio frequency (RF) energy.

Abstract: An apparatus and method for issuing busy call-backs (146) on the voice channel to busied communication units (209,211) on a trunked radio communication system (200) is disclosed. This is accomplished, in part, by issuing a busy signal (104), via a control resource (203), to a communication unit when a requested communication resource is unavailable. Additionally, the radio communication unit (209,211) is capable of receiving the busy signal via the control resource (213) and participating in a second communication while in a busied state. The resource controller (201) is capable of allowing the busied communication unit (209,211) to participate in a second communication on a second communication resource (215) and issuing the call-back signal during the second communication.

Abstract: A surface mountable piezoelectric device that includes an in situ finish plate mask is mounted on a substrate (20) that includes feedthrough holes (26, 28, and 30) to conduct signals from a piezoelectric element (40) that may include multiple resonator stages (48, 46, 50, and 56). A metallic support structure that includes windows or holes therethrough (72, 74 and 76) permits tuning of the piezoelectric device by mass loading during manufacturing, compliantly supports the piezoelectric element (40), provides RF shielding for the resonators, and is an in situ finish plate mask.

Abstract: A radio having two signal processing paths, one including a digital signal processor that consumes a relatively large amount of power and one including a signal processor that consumes a relatively small amount of power. The low power processor operates to monitor for broadcast signals of interest. Upon detecting such a signal, the low power processor enables the digital signal processor to facilitate proper signal processing.