Abstract: An balun/antenna apparatus is provided which is capable of being fabricated on a printed circuit board substrate by automated equipment. The balun-antenna includes a microstrip groundplane conductor which is split into two balanced ground arms at one end. The split groundplane conductor operates as both a balun and as a radiating conductor. A unique microstrip excitation structure is situated above the split ground elements on the opposed surface of the substrate to excite the antenna with radio frequency energy.

Abstract: A self-retaining actuator is provided for actuating a switch within a housing. A lever includes fingers which extend through a hole in the housing. Lips on the fingers mount the lever to the housing. A resilient seal is positioned about the fingers and engages the lever and housing about the hole. A resilient actuator extends from the seal between the fingers to actuate the switch when the lever is depressed.

Abstract: An electronic lock system for a two-way radio. The radio is locked by entering a security code. While locked, the keypad is disabled and cannot be used. In order to unlock the keypad, the proper three-digit code must be entered. If an improper code is entered, the radio automatically transmits a message to indicate the identity of the radio and that an improper code has been entered.

Abstract: A contact assembly is provided for interconnecting a circuit board and a coaxial connector. A formed metal element provides a strip of electrically conductive material which is connected to and supported by the circuit board. A center contact arm extends from the strip to engage the coaxial connector. A second formed metal element includes a ground plane which is supported by the circuit board in spaced relation to the strip. A ground contact arm extends from the ground plane to engage the coaxial connector. A dielectric member is positioned between the strip and the ground plane.

Abstract: A retaining washer (100) prevents the rotation of a D-shaped shaft (106) which is mounted in a round hole (105a) of a housing (105). The retaining washer includes a substantially flat washer (101) having a hole (101a). A tapered tab (102) includes a wide end (102a) and a narrow end (102b). The tab is attached to the flat washer at the wide end such that the tab is substantially perpendicular to the flat washer. A gusset (103) is attached between the tab and the flat washer. The gusset includes a lower edge (103a) which is positioned at an obtuse angle (104) relative to the flat washer. The gusset indents into the housing (105b) and the tab is forced against the flat portion (106b) of the D-shaped shaft. The upper left and right edges of the tab cut into the wall of the housing hole (105c and 105d).

Abstract: A detachable low profile mounting clip arrangement suitable for use with a portable hand-held electronic apparatus such as a paging receiver, includes a housing having a slot. A base member has a hook attached to one end and a pair of apertures at the other end. The hook engages in the slot of the housing while the apertures spring over a pair of wedge shape protuberancies in the housing and snap into place. A mounting clip or lanyard is attached to the base member.

Abstract: A synthesizer circuit with spur compensation utilizes fractional division in the synthesizer loop. Two accumulators are utilized for determining the divisor value N. The capacity of the two accumulators is selectable. An offset value is selectively introduced into the accumulators in order to produce a waveform having an acceptable spurious content.

Abstract: A quadrature amplitude modulation system utilizes two subcarrier signals, each quadrature modulated with information signals which are quadrature modulated onto the RF carrier. This provides a hole in the center of frequency spectrum, permitting carrier and bit sync signals can be provided in the center area of the signal spectrum.

Abstract: A radio communication receiver decodes digital signals transmitted over a radio link and is capable of altering the bit rate of the receiver to match the bit rate transmitted form a remote location. The receiver includes a receiver portion 21 receiving radio signals and producing a received signal. A microporocessor 26 is used for decoding the received signal. The microprocessor (26) is responsive to a bit rate signal that is generated by a programmable divider (33). The microprocessor (26) is adpated to detect a predetermined code signal to alter the timing characteristic of the bit rate signal for generating a bit rate signal at a second rate for decoding received signals at a second bit rate designated by the predetermined code signal.

Abstract: A dual FET oscillator includes a first J-FET and a second J-FET connected to it as a source follower. A turned circuit is connected to the gate of the first J-FET and to the second J-FET. Bias voltage is supplied to both J-FET's. Schottky diodes are connected to both J-FET's to limit gate-source voltage.

Abstract: A Ga As FET oscillator includes an FET having gate-drain and source connections. A tuned circuit is connected to the FET gate. Bias voltage is supplied to the FET. A parallel-connected resistor and capacitor is connected to the FET source. A Schottky diode is connected across the FET gate-source junction and the parallel connected resistor and capacitor, with its anode connected to the FET gate and its cathode connected to the resistor and capacitor. The Schottky diode limits the positive voltage across the gate-source junction of the Ga As FET to prevent gate-source current flow.

Abstract: A header for an electronic circuit includes two complementary portions. The electronic circuit is a flexible circuit with leads on opposite side edges. The opposite side leads are received by the header portions and fixed in place as by epoxy. The two header portions are then snapped together to form the header. One of the header portions includes tongues which are received in slots of the other header portions for maintaining alignment of the two portions. Clips are provided on each of the header portions for interconnecting with complementary clips of the other header portion.

Abstract: This tone decoder utilizes three correlators for detecting the presence of a desired tone signal. A main correlator correlates to the desired tone frequency, while two side correlators are used to correlate to frequencies above and below the desired tone frequency. Tone detection is indicated by correlation of the main correlation and absence of correlation by the side correlators. Improved bandwidth and/or correlation time is achieved as compared to utilizing a single correlator.

Abstract: A trimmable current source for use with low voltage circuitry includes a plurality of trimming networks. A voltage-divider circuit is connected to the trimming networks. Each of the trimming networks includes a resistor in an isolated epitaxial region series connected to a zener diode. A programming signal, having a voltage level which would normally damage the low voltage circuitry can be applied to the junction of the resistor and zener diode, and to the isolated epitaxial region containing the resistor of the trimming network to be programmed without damage to the low voltage circuitry.

Abstract: This is a selector circuit for an electronic device such as a pager that has a plurality of functions with each of the functions having a plurality of levels. First and second switches are provided for selecting the functions and levels. A controller such as a microprocessor is responsive to the first and second switches for selecting the functions and levels. The functions are selected by first actuating the first switch and then actuating the second switch while the first switch is maintained actuated. Levels of selected functions are selected by first actuating the second switch and then actuating the first switch while the second switch is maintained actuated.

Abstract: The molded resonator includes at least one formed resonator element having an resonator portion and opposed end leg portions which provide electrical connections to the main portion. A dielectric portion is molded about the resonator element. A conductive ground plane is carried by the dielectric portion and electrically shields the resonator element. The resonator element is formed of wire having a circular cross-section.

Abstract: For proper pre-assembly alignment of the hinge plate holes (e.g., 120b and 136b), stops (e.g., 140a) are engaged in notches (e.g., 119b). A hinge pin (128) is then inserted into the aligned holes to attach the clip (130) to the base plate (102). The pin is locked in position by a spring finger (204) that forcibly engages the semicircular wall (202) of one hinge plate hole (120a) into a groove (304) on the pin. A coil spring (122) is unloaded during assembly because its free ends (124a and 124b) project through apertures (116a and 116b) in the base plate. After assembly, the spring is pre-loaded by engaging its free ends under tabs (116a and 116b) that project into the apertures. The base plate has a "U" shaped bracket (502) at one end and a tab (112) on a torsion bar (110) at the other end to attach the assembly to a radio housing.