Abstract:
Systems and techniques for adaptive interference filtering in a communications device are disclosed. The communications device may include a transmitter, a receiver, a duplexer coupled to the transmitter and the receiver, and an adaptive filter disposed between the duplexer and the receiver. A processor may be configured to monitor cross modulation in the receiver between transmitter leakage through the duplexer and a jammer, and adapt the filter to vary its transmit signal rejection as a function of the cross modulation.
Abstract:
A wideband Voltage Controlled Oscillator (VCO) uses a resonant circuit tunable over a wide range of resonant frequencies. The resonant circuit includes voltage variable elements such that the resonant frequency, and thus the frequency of oscillation, may be electronically tuned. The voltage variable elements are arranged such that multiple control voltages determine the resonant frequency. A first control voltage is applied to a first set of tuning elements and operates as a coarse control of the resonant frequency. A second control voltage is applied to a second set of tuning elements and operates as a fine control of the resonant frequency. Using multiple control voltages on multiple elements allows for a wideband VCO while maintaining a low VCO gain.
Abstract:
A tunable SAW resonator circuit (400, 500) is disclosed. The tunable SAW resonator circuit includes a SAW resonator (404a, 404b, 504) having a quality factor and a resistor (412a, 414a, 510, 512) coupled to the SAW resonator to reduce the quality factor Q and a tuning component (402a, 502) coupled to the SAW resonator to tune the SAW resonator. A method to tune the SAW resonator is also disclosed. The SAW resonator may be tuned by applying a control signal to the tuning component (402a, 502).
Abstract:
An efficient radio communications device. The device includes a computer and a balanced antenna system that delivers electromagnetic energy to and from the computer via a radio section. The radio section is connected to the computer and the antenna feed and interfaces the antenna system to the computer to facilitate electrical communication between the computer and the antenna system. The balanced antenna system includes an antenna feed for extending radiating elements of the antenna system from the computer to reduce electrical coupling and interference between the computer and electromagnetic energy radiated or received by the antenna system. The antenna system includes a ballun that interfaces the antenna feed to the radio section. In an alternative embodiment, the balun interfaces the antenna radiating elements to the antenna feed. The balun is a lumped or discrete element balun or a bazooka balun. The antenna feed includes a coaxial transmission line. The balanced antenna system includes a dipole antenna. The dipole antenna has approximately symmetrical radiating elements oriented in opposing directions. The radio section includes a transceiver and a duplexer that is connected between the antenna system and the transceiver and facilitates the sharing of antenna system resources between transmit and receive functions.
Abstract:
A connector interface (68) provides direct connection from a wireless communication device to a coaxial connector. The wireless communication device has a housing with an antenna connector. The antenna connector has a hollow pseudo-cylindrical center providing an opening through the housing. The connector interface has a custom connector (66) comprised of an outer conductive shell (72), a nonconductive spacer (76) and a ground probe (78). The outer conductive shell (72) is mounted on the printed circuit board (70). The nonconductive spacer (76) is disposed within the hollow pseudo-cylindrical center of the outer conductive shell (72). When the connector interface is connected to the wireless communication device, the outer conductive shell (72) contacts the antenna connector and the ground probe extends through the opening into the housing to connect electrically to a ground potential within the housing.
Abstract:
Systems and techniques for adaptive interference filtering in a communications device are disclosed. The communications device may include a transmitter, a receiver, a duplexer coupled to the transmitter and the receiver, and an adaptive filter disposed between the duplexer and the receiver. A processor may be configured to monitor cross modulation in the receiver between transmitter leakage through the duplexer and a jammer, and adapt the filter to vary its transmit signal rejection as a function of the cross modulation.
Abstract:
A selectively coupled two-piece antenna for use in a mobile phone having a casing (102) and radio frequency (RF) communications circuitry (112) includes a composite radiator (206) that is selectively extendable from and retractable into the casing and a communications interface that is connected to the RF communications circuitry. The composite radiator has first and second radiating elements (208, 212), and a connecting element (210). When the composite radiator is extended, the connecting element connects the first and second radiating elements. In this position, the communications interface connects the RF communications circuitry to the first and second radiating elements. Thus, the RF communications circuitry transmits and/or receives RF signals through both the first and second radiating elements as a top loaded antenna. However, when the composite radiator is retracted, the connecting element electrically isolates the first and second radiating elements. In this position, the composite radiator electrically connects with the communications interface so that the first radiating element is electrically connected to the RF communications circuitry.
Abstract:
A dual-band antenna system for use in a portable communications device is disclosed herein. The antenna system includes an antenna element (10) for radiating electromagnetic energy within low-band and high-band wavelength ranges. In a preferred embodiment, a low-band isolator network (20), coupled to the antenna element (10), provides signal isolation between high-band and low-band signal paths during high-band operation. Similarly, a high-band isolator network (18) provides signal isolation, during operation over the low-band range of wavelengths, between the high-band and low-band signal paths. During transmit and receive operation, low-band and high-band electromagnetic energy directed through the antenna (10) is passed by the low-band and high-band isolator networks, (20) and (18) respectively. Also included are low-band and high-band matching networks (28) and (36), respectively, which couple the low-band and high-band isolator networks (20) and (18), respectively, to low-band and high-band transceiver circuitry.
Abstract:
A double helix antenna (10) comprised of orthogonally-wound helix conductors. The double helix antenna (10) includes a first helix conductor (14) wound in a first direction about a vertical axis, V, of the double helix antenna (10). A second helix conductor (18) is wound in a second direction about the vertical axis, V. In a specific implementation, the first and second helix conductors (14 and 18) are of different lengths, respectively corresponding to first and second frequency bands. Additionally, the first and second helix conductors (14 and 18) are wound so as to be orthogonal at those horizontal planes within which the first and second helix conductors (14 and 18) intersect or are otherwise minimally separated in the horizontal dimension. This orthogonal winding relationship between the helix conductors substantially reduces mutual coupling, thus enabling operation of separate helical antennas in close physical proximity.
Abstract:
A system for modularizing the functionality of an electronic device (10). The system includes a first mechanism for separating different functional blocks of the electronic device into spatially separable hardware modules (12, 14, 16). A second mechanism interfaces the hardware modules via spatially reconfigurable communications links (38, 40). In a specific embodiment, the spatially reconfigurable communications links are infrared links or optical links.