Abstract: Surface acoustic wave devices (160) as well as other electronic devices, can be mounted into the sides of ceramic blocks (150) that comprise a ceramic block filter device. The surface acoustic wave device as mounted in the filter block does not require or displace volume that would be required to mount the surface acoustic wave devices in their own housings.

Abstract: An ultra thin piezoelectric quartz crystal package can be realized by using adhesive dollops to compliantly mount a piezoelectric device within a thin package. The adhesive dollops maintain spacing between the upper and lower surfaces of the piezoelectric device (18) and the surfaces (13 and 15) of the housing that is comprised of upper and lower substrates (12 and 14).

Abstract: In applications where mechanical vibrations should not cause a microphone to produce an output signal, opposing and series connected PZT elements (A and B) are used to cancel mechanical shock or vibration that might cause an output voltage or signal. Acoustic waves cause the PZT elements to deflect in opposite directions which when the sensors (A and B) are electrically in series produce a measurable output.

Abstract: A pseudo rod, fabricated from several plate sections joined together at their edges and having a cross-section resembling a polygon approximates a rod having a circular cross section. Using multiple plates joined at their edges permits growing a crystalline material on the planar faced substrates and if the plates are crystalline material, the crystalline material grown thereon can have improved current carrying capability.

Abstract: A method of synchronizing a plurality of remote site transmitters (200) in a digital simulcast transmission system is described that enables use of four-level modulation on two-level modulation systems. A synchronization signal is transmitted at a predetermined data rate from a prime site, which signal might include a synchronization pattern having a first and a second portion. The first portion of the synchronization pattern is used for synchronization, while the second portion indicates the completion of the first portion. The method includes detecting (205, 320) of the first portion of the synchronization pattern. Each remote site transmitter (200) further has a modulation clock having a phase polarity which is selected (215, 324) in response to the detection of the first portion of the synchronization signal.

Abstract: A method (215) of converting a current control channel for use as a communication (voice/data) channel, in order to maintain a predetermined level of service in a radio communications system, employs a central controller (101) to allocate a limited number of communication channels among a plurality of subscriber units (108-112). After receiving (203) a request for a communication channel from one of a plurality of subscriber units (108-112), the controller (101) determines (205) whether all of the communication channels are busy. The controller then temporarily converts (215) the current control channel to a communication channel.

Abstract: In-situ adjustments to frequency characteristics of an electronic device such as a piezoelectric element (40) can be accomplished by means of a predetermined atmosphere (18) enclosed within a package comprised of a base (12) and a cover (14) and an included amount of sputterable electrode material (22). By attachment of appropriate electric potentials (2), electrode molecules can be sputtered onto the electrode surfaces adjusting the resonant frequency characteristics of a crystal filter.

Abstract: A communications system receiver (100) is disclosed which receives a transmitted signal over a radio channel. The transmitted signal includes data and a predetermined synchronization sequence. The receiver (100) includes a demodulator (215), and a stored replica (207) of the predetermined synchronization sequence. The receiver (100) further includes apparatus (102) for computing (308) a reconstructed signal, by using the channel impulse response characteristic and the stored replica (207) of the synchronization sequence. A feature of the invention is to estimate (310) a phase offset value between an incoming signal and the reconstructed signal, for a plurality of synchronization symbols. This serves to establish (315) a relationship between the phase offset and a synchronization symbol index. The receiver then employs this relationship to derive (317) at least one "previous" phase state (214) for initializing (314) the demodulator (215).

Abstract: A dielectric block filter having a self aligning, top and shield is provided. Recesses are formed in at least one side of the block, which recess is dimensioned to accept a mating tab or side of a shield that substantially encloses the top end of the filter. The recess in the block in combination with the appropriately shaped tab produces the overall height of the filter and simplifies manufacturing by eliminating the need to hold or affix the shield to otherwise smooth sides of the block.

Abstract: A method and apparatus for operator messaging within a radio communication system (200) using a resource controller (203), which allocates a plurality of communication resources among a plurality of communication units (213, 215), is disclosed. Each of these communication units may be used by an operator having an operator code (262) and associated with a message (264, 266). This operator code and message, along with identification codes (252) representing each of the plurality of communication resources, are stored in a database (201) within the resource controller (203). The method includes the transmitting of the identification (ID) associated with a transmitting communication unit, matching this ID with one of the stored identification codes (252) in the database (201), and using this code to retrieve the message (254, 256) associated with the operator of this communication unit.

Abstract: A method of automatic path map generation (600) for use in a simulcast transmission system is disclosed which has at least three transmitter sites which form a first communication loop (403). The first communication loop has at least a first and a second audio path. A first audio path originates from a primary transmitter site (402), passes first through a first transmitter site, and ends at a second transmitter site. A second audio path originates from the primary site (402), passes first through the second transmitter site, and ends at the first transmitter site. The first audio path is associated with a first path condition, and the second audio path is associated with a second path condition. The method employed includes establishing (601) a logical representation of the simulcast transmission system.

Abstract: A dielectric resonator (400) is formed, according to the invention, from a block of dielectric material having top, bottom, and side surfaces. A protuberance (407) is formed on at least the top surface of the block. Further, a hole (405) is formed through the block, which hole extends substantially from the apex of the protuberance, through the block, to the bottom surface. The hole and protuberance combine to form a mesa structure (604, 704). The bottom surface, side surface, and an interior surface of the hole (405) are coated with a conductive layer. Further, a conductive coating is selectively disposed on the top surface of the block, which coating at least partially covers the mesa (604, 704). A dielectric block resonator (400, 500) is thereby formed whose resonant characteristics are at least partially determined by the physical dimensions of the mesa (604, 704).

Abstract: A multi-stage ceramic bandstop filter electrically isolates coupling between stages in a monolithic block of ceramic material (21) by including holes (32 and 36) between the resonator stages (30, 34, and 38) that are shorted at both the top and the bottom ends, that are coated with conductive material and that behave as electrical shields between the succeeding resonator stages electrically isolating and reducing signal coupling between stages. Isolation between stages is also provided by impedance inverting lengths of transmission line (50 and 52) that coupled the stages together.

Abstract: A data transmission system receiver is disclosed which receives a formatted data stream (302) and operates in one of at least a first bandwidth mode and a second bandwidth mode. The formatted data stream (302) comprises a plurality of data edges (108, 110) and is sampled by a first clock signal (320). A plurality of clock edges (102, 104) defining transitions from one logic state to another is used to define "early" and "late" data edge occurrences. These occurrences are accumulated in accumulators (310, 312) and used as inputs to a clock counter (318) which produces a phase-adjusted clock signal (320). Additionally, the data transmission receiver comprises a detector (330) for detecting when a limited data stream (306) is synchronized with the phase-adjusted clock signal (320) and, in accordance with a predetermined algorithm, is able to switch the phase-lock circuit from the first bandwidth mode to the second bandwidth mode.

Abstract: Heat-generating ovenized crystal oscillators can be directly mounted to a circuit board. Thermal isolation of an OCO from heat-sinking circuit board material and other temperature-sensitive components on a circuit board is accomplished by means of perforations (12) in the circuit board that surround the mounting area of the OCO on the board.

Abstract: In certain computerized systems, computer-generated spoken instructions are made more natural sounding by using recursion to identify significant points in a series of similar instructions when an utterance should be made. No instructions are issued when such instructions would provide little or no information to a user. In a vehicle navigation system, instructions to a driver are typically issued at points along the drivers route where the driver should perform some critical action.

Abstract: A trunked radio system range extender extends the range of a trunked radio system by having a second repeater station monitor the control channel for the trunked radio system detect and decode control information and rebroadcast it on to a second control resource. Communications resources from the first trunked radio system are similarly mapped into a second set of communications resources for subsequent broadcast throughout an extended geographic range. The extending repeater station uses the control resource from the first repeater station.

Abstract: In those monolithic ceramic filters that require resonator stages formed within a block of dielectric material to be electrically coupled together through discrete components, namely wires (44 and 46), a substantial space savings as well as improved electrical and mechanical performance can be realized by mounting the wires (44 and 46) within de-coupling cavities (36 and 40) when such de-coupling cavities are available and properly positioned with respect to the other resonator elements in the filter.

Abstract: An enclosure system (100) is disclosed which has a conductive cover shield (102) which is retained in contact with a substrate (104) having a radio frequency (RF) circuit disposed thereon. The enclosure system (100) is made up of a conductive area (116), disposed on the substrate (104) peripherally about the electrical circuit which is then connected to the conductive cover shield (102). This connection allows for substantial horizontal displacement (305, 305') of the substrate material (104). The natural resilience of the substrate (104) material then allows for substantial vertical displacement of the conductive cover shield (102) with respect to the substrate (104) without substantial loss of contact pressure between the conductive cover shield (102) and the conductive area (116). Additionally, this form of connection provides for at least partial isolation of the RF energy from an environment outside of the enclosure system.

Abstract: Improved frequency characteristics can be achieved by using input/output pads on a surface mount block filter which pads are mounted on mesas formed by troughs cut through the dielectric material and metallization.