Abstract: A twisted-pair conductor line structure is formed on a substrate (22) having insulated conductive layers (10, 11). The conductive layers are used to form first, second, third, and fourth conductive planar segments (16). A first conductive link (17) joins the first and second planar conductive segments to provide a first signal path. Similarly, a second conductive link (17) joins the third and fourth planar conductive segments to provide a second signal path. The first and second conductive links are operatively arranged to form a twist (17)in the first and second signal paths, such that the resulting magnetic fields (57, 59) around the twisted conductive segments will be opposite to each other for cancelling each other out, in order to reduce the magnetic field radiation to the surrounding environment.

Abstract: A volume control circuit comprises a variable gain stage (306), having a variable gain, and an up/down counter (324) for counting. The counter (324) has a counter input (321) and a counter output (333) for providing a first word (333) for controlling the gain of the gain stage. A microprocessor interface (326) includes an interface output (323) for providing a second word. A digital magnitude comparator (333) compares the first (323) and second (333) words. The comparator having a first input (333) connected to the counter output, a second input connected to the interface output (323), and a comparator output connected to the counter input (321), provides a count signal (329) if the words do not match and for providing a non-count signal (329) if the words match. Thus, responsive to the count signal (329), the up/down counter (324), counts from the first word, in a direction approaching the second word by a least significant bit to form a new first word, for controlling the gain of the gain stage.

Abstract: A twisted-pair conductor line structure is formed on a substrate (22) having insulated conductive layers (31, 32). The conductive layers are used to form first, second, third, and fourth conductive planar segments (40, 41, 42, 43). A first conductive link (44) joins the first and second planar conductive segments to provide a first signal path. Similarly, a second conductive link (46) joins the third and fourth planar conductive segments to provide a second signal path. The first and second conductive links are operatively arranged to form a twist (17) in the first and second signal paths, such that the resulting magnetic fields (57, 59) around the twisted conductive segments will be opposite to each other for cancelling each other out, in order to reduce the magnetic field radiation to the surrounding environment.

Abstract: In a radio transceiver having a microcomputer (11) that controls various hardware-dependent components (220) and functions (240) that form a plurality of radio control processes, a method and apparatus for executing the radio control processes includes providing the microcomputer (11) with a plurality of virtual sources (272). The virtual sources (272) are for collecting and distributing data (440) generated by the hardware-dependent components (220) and functions (240) in the radio transceiver. A plurality of hardware-independent tasks (292, 392) for executing the radio control processes are also provided by the microcomputer. A distribution controlling interface standard (228) for controlling which hardware-independent task (292, 392) will receive from which virtual source (272) is further provided by the microcomputer (11).

Abstract: To reduce crosstalk in reentrant off-chip RF selectivity, differential circuits (402, 415), transmission lines (423, 424), and off-chip filters (422) are used in a structure that balances the parasitic capacitances associated with all of the differential elements. The structure includes a substrate (409) with a differential generating circuit (402) and a receiving circuit (415). Two differential transmission lines (423, 424), each with constant characteristic impedance, and each with balanced capacitance to ground, both being closely spaced for some distance, couple the circuits (402, 415) to closely spaced terminating pads (403). A ground plane (412) is shared under both transmission lines (423, 424). A second substrate (408) having a reentrant RF path (406) with the first substrate (409) contains an RF function such as a filter or a delay line.

Abstract: In radio processing control (11), a plurality of architectural layers (270, 290, 390) separate at least one of a plurality of tasks (272) from another task (292). For communicating among the tasks within (274, 276, 278) or across (229, 239) the layers, a buffer (300) for each of the tasks is provided by a communication resource (602). A messaging protocol for passing information from the tasks is defined to be a predefined information packet having a header (700) preceding any optional data. A flag portion (701) of the header designates the information as intralayer or interlayer. If the information is interlayer (229, 239), an identifier portion (703, 704) of the header identifies the source (272) of the information and an operation portion (702) identifies an operation code.

Abstract: A transceiver (100) is provided for transmitting during the transmission bursts (12) of a frame and receiving during the receiving time-slot windows (14). The transceiver (100) includes a receiver (320) for receiving a repeating radio frequency data (16) signal at any time within the receiving time-slot window (14) and for demodulating the repeating radio frequency data signal down to a baseband data signal. A data detector and clock recovery device (330) recovers the valid data (CHMP) from the baseband data signal. For controlling the receiver (320) and data detector and clock recovery device (330), a control circuit (400) modifies the receiving time-slot windows (14) to only receive and detect when valid data is expected (52).

Abstract: A battery charger for charging a battery (4) for a radio (12), is provided having two terminals (6 and 8). A charging circuit (24 and 26) has a controllable parameter for charging the battery (4). An operational mode detector (30) is coupled to the two terminals (6 and 8) for detecting an operational mode of the radio. A control circuit (22) is coupled to the operational mode detector (30) and to the charging circuit (24 and 26) for controlling the controllable parameter in response to the operational mode detected.

Abstract: A method and apparatus for reducing the settling time of a switched-capacitor circuit (10) which includes at least one capacitor (20) having at least one terminal connected to a switch. The method comprises the step of clocking the switched-capacitor circuit at a switching clocking frequency. In response to a control signal (51), the at least one terminal of the at least one capacitor (20) is biased to a reference voltage potential.

Abstract: A receiver (10) is provided where an information signal (11) is received (12) and examined to determine (20) its signal strength. When the signal strength is at least equal to a threshold, an unmodulated signal (40) is added to the received signal to improve the sensitivity of the receiver.

Abstract: A switch assembly comprises a substrate (10) having conductive traces providing contacts (23) on the substrate (10) and a connector (21) positioned over the substrate (10). The connector (10) includes an actuator area (33) and a selectively conductive area (22) located perpendicular to the actuator area (33). The selectively conductive area (22) is located over the contacts (23) and is made electrically conductive with the contacts (23), when the connector (21) is shorted with an actuator, the actuator area being at a fight angle to the conductive traces.

Abstract: An improved circuit protection device (30) comprises a PTC element (10), at least two electrodes (2 and 3) connectable to a source of electrical power (12) so that current passes between the electrodes (2 and 3) through the PTC element (10), and at least one nichrome electrical lead (122, 123) which electrically connects one of the electrodes (2, 3) to the source of electrical power (12).

Abstract: An antenna connector and RF switch assembly (10) is provided on a portable radio (14). The radio includes a self-contained antenna (16) and a radio circuit (27). The assembly (10) is used for selectively connecting the radio circuit (27) to the antenna (16) or to an external signal supply (39). In the assembly, a switchable conductive center contact portion (22, 20, 35) selectively engages either the antenna (16) or the external signal supply (39). A metallic housing (18), having an antenna bushing (17), receives the antenna (16). A molded dielectric insulator portion (26) separates the switchable conductive center contact portion from the metallic housing and is directly connected to the antenna bushing.

Abstract: A clock recovery system for radio communication inserts a synchronization signal (102) at a frequency of 1/2 the baud rate, at the spectral null of an MSK data signal (108), which is also at 1/2 the baud rate, for later retrieval. Hence, in a transmitter-encoder (100), an MSK generator (106) generates an MSK digitally modulated data signal (108e) having a baud rate and a spectral null at 1/2 the baud rate. A synchronization clock generator (104) generates a synchronization signal (102e) having a frequency at 1/2 the baud rate. This frequency at 1/2 the baud rate corresponds to the spectral null of the MSK digitally modulated data signal (108e). A transmitter transmits the synchronization signal (102e), at the spectral null of the data signal (108e), together (112) with the MSK digitally modulated data signal (108e).

Abstract: Briefly, according to the invention, a compression seal between two surfaces is provided by a body portion (212) conforming between the two surfaces (110 and 130). A first (211) and second (311) rim are connected to a perimeter of the body portion (212). For providing a seal between the two surfaces when the two surfaces are compressed against each other, the second rim is connected to the first rim at an angle (216) between 0 and 180 degrees.

Abstract: A process for fabricating an electromagnetic shield for a display provides for a sheet upon which a metal mesh pattern and a border surrounding the metal mesh pattern is photo-chemically etched on the sheet. In addition, a portable radio having an electromagnetic shielded display provides for a bordered metal mesh disposed between a cover and a display.

Abstract: A combined keypad and speaker portion (10) is provided wherein a membrane keypad (26) having a plurality of keys (28) has a plurality of speaker sound perforations (38) interposed between the plurality of keys (28).