Abstract: An evaporative cooling vessel (100) for controlling the temperature of a predetermined portion of an electronic part during the solder reflow process. The evaporative cooling vessel (100) includes a cavity (105) for holding a fugitive material (107) at the housing (111) of an electronic part to maintain the housing at or below a specified temperature. As heat is applied during solder reflow, the electronic part is subjected to a high temperature capable of allowing solder to melt. Thus, the part housing (111) of the electronic part can be controlled at a substantially lower temperature than the reflow temperature. This allows the evaporative cooling vessel (110) to use the evaporative cooling properties of the fugitive material to prevent damage to the electronic part.

Abstract: An antenna assembly (100) for use in a portable two-way radio communications device includes a radio housing (101) including one or more boss (103) used for securing portions of a substrate (105) to the radio housing. An aperture (115) located within an antenna housing (111) is positioned over an antenna boss (107) where a metal trace located on the substrate (105) can be electrically connected to the antenna housing (111) using a fastener (109). The antenna assembly (100) permits an antenna element (113) located in the antenna housing (111) to be easily connected to the substrate (105) using minimal component parts while fastening both the antenna housing (111) and substrate (105) into a fixed position.

Abstract: A high Q planar resonator (200) which includes a plurality of interconnected planar runners (209, 211, 213) which decrease in width on multiple layers of substrate material (203). The invention produces a high Q by using multiple conductor layers as the center conductor to reduce current crowding.

Abstract: A low loss electronic radio frequency (RF) switch (100) for switching RF energy between an antenna port (115), a receiver port (113) and a transmit port (101) used in a two-way radio transceiver. The RF switch includes a first diode (105) connected between the transmit port (101) and the antenna port (115). A first capacitor (103) is connected between the transmit port (101) and a ground potential while an inductor (107) and second capacitor (111) are serially connected between the antenna port (115) and a receive port (113). A second diode (109) is connected between the inductor (107) and the second capacitor (111) and the ground potential. The antenna port (115) is normally connected with the receive port (113) when idle. When direct current is applied to the transmit port (101) the first diode (105) and second diode (109) are biased into a low impedance state connecting the antenna port (115) to the transmit port (101) and isolating the receive port (113) from the antenna port (115).

Abstract: A portable communication device with battery conservation capability is capable of sensing (223) its power source and suppressing a battery conservation circuit depending on an actual voltage determined (225) from an analog-to-digital converter. Two or more voltage ranges are defined (227) such that battery conservation is disabled when an external power source is operated in one of the predetermined voltage ranges.

Abstract: A multi-layered coupling device (FIG. 9) for coupling radio frequency (RF) energy on a transmission line (302) to a coplanar coupler. The coupling device includes a first coupling structure that is coplanar with the transmission line (302) and parallel plate structure (304) positioned a predetermined distance in a plane parallel to the transmission line (302). The parallel plate structure (304) is not physically connected to any other structure through the use of vias or the like. The parallel plate structure (304) is used to increase the coupling coefficient and directivity of the coplanar structure by being divided into a plurality of segments with varying dimensions to better control coupling capacitances.

Abstract: A method of calibration of a power amplifier for a radio transmitter is described (FIG. 6), which is particularly relevant to the field of training of linear power amplifiers. In a calibration mode, an increasing signal, e.g. a ramp signal (153), is provided to the amplifier until the amplifier commences clipping (155). A value for said input is identified (155) which does not cause clipping. Thereafter, in operational mode, the increasing input signal is limited to that level. In this manner, interference during training is avoided. A radio transmitter is also provided.

Abstract: A remote microphone display select system (200) used with a two-way radio (201) for controlling the orientation of displayed information includes a remote microphone (101) which is electrically connected to a display driver (203). A hall effect switch (207) is used with the display driver (203) and acts to alter the orientation of displayed information on a display (106) to either a first orientation or second orientation when the hall effect switch (207) is disabled.

Abstract: A method of actuating a plurality of power amplifier devices in an Class D audio switching amplifier (100) using non-overlapping edge drive signals for preventing substantially high current spikes during switching transitions. The method includes actuating and deactuating power amplifier devices within a first complementary power switching device (117) and actuating and deactuating a second complementary power switching device (119) using a plurality of drive signals generated by a non-overlapping driver (107). The method provides that the first complementary power switching device (117) and the second complementary power switching device (119) are switched ON and OFF in a predetermined sequence such that more than one power amplifier device within each complementary power switching pair is prevented from being simultaneously activated. This prevents high current spiking and subsequently high current drain during a switching transition for conserving battery life when used with portable equipment.

Abstract: A stencil shifter (800) for positioning a differential thickness stencil stencil (14' integrally formed from two sieves (601 and 602) having different thicknesses (701 and 702) for a two-stage solder printing process for printing the solder mask for a fine-pitch component alongside that of a larger component on the same side of a printed circuit board. This same stencil shifter (800) can also be used for a top and bottom side two-stage printing process. This two-stage printing process uses an integral stencil (814) having a plurality of sieves (801 and 802), the plurality of sieves including at least a first sieve (801) for paste stenciling a first side (191) of a board and a second sieve (802) for paste stenciling a second side (202) of the board. What side the board is facing is first determined by an optical sensor (193) and in response to the side detected, the integral stencil (814) is positioned to locate one of the pluralities of sieves over the board for printing that side.

Abstract: A signaling protocol for an infrastructureless short range communication system uses slow frequency hopping compatible with the industrial/scientific/medical (ISM) frequency spectrum. The signaling protocol utilizes a multi-tiered structure having an acknowledgment request frame (200), ping frame (300), connect frame (400) and voice frame (500). These frames are used to determine an appropriate allocation of frequency spectrum from an initiating station (11') to at least one other non-initiating station (11). The signaling protocol allows an initiating station (11') to rapidly identify other stations (11) within a talk group (13) and resolve actual and/or potential collisions to establish clear and reliable infrastructureless communication.

Abstract: A radio transceiver system (100) includes an option board interface (117) with an analog interface (119) and a digital interface (125). Option board interface (117) is used for conveying information between an optional memory board (133) and a digital processing unit (105). Option board interface (117) also controls analog audio functions through analog interface (119). Option board interface (117) enhances functional operation of the radio transceiver system (100) by allowing options to be selected which are not provided as standard radio equipment.

Abstract: A multi-purpose fastening assembly (131) which can be used for both securely fastening and charging an internal battery (113) located within a wireless microphone (103). The fastening assembly (131) includes a head portion (133) and a base plate (135) which are electrically isolated so they can be used as electrical terminals for recharging the battery (113) within the wireless microphone (103).