Abstract:
A wireless communication unit (200) comprises a radio frequency (RF) receiver for receiving an RF signal and providing the received RF signal to an off-channel signal detector (218) and a quadrature down conversion mixer circuit comprising at least one dynamic matching mixer stage (226, 228, 250, 252). The off-channel signal detector (218) is arranged to detect whether an off-channel signal level of the received RF signal exceeds a threshold and, in response to determining that the received off-channel RF signal exceeds the threshold, the off-channel signal detector (218) deactivates the at least one dynamic matching mixer stage. Also described is a semiconductor that comprises a receiver, and a method of operation therefor.
Abstract:
An antenna assembly (10) includes a ground plane formed on a chassis (12) of the radio and the functional knob forming an antenna element (11). The antenna assembly further includes a slot or notch element (14) in the ground plane substantially adjacent to the functional knob and having a length less than ¼ wavelength, and a coaxial cable (13) feeding the antenna element. A shield of the coaxial cable can be directly connected to the ground plane and a center conductor of the coaxial cable can be directly coupled to the functional knob to provide a galvanic connection for narrowband performance or the center conductor can be electromagnetically coupled to the functional knob for wideband performance or both. The antenna assembly can create a zero volume notch type ground excitation.
Abstract:
An antenna and methods for manufacturing the antenna is provided. The antenna (100) includes an electrically non-conductive substrate (102). The antenna further includes an electrically conductive strip (104). The electrically conductive strip (104) is wound around the electrically non-conductive substrate (102) so as to form an overlap (120) between adjacent turns of the electrically conductive strip (104), without creating a galvanic connection at the overlap.
Abstract:
An antenna arrangement (1000) for use in an RF communication terminal including a plurality of resonators (1003, 1005, 1007, 1009) formed from a plurality of conducting wires (1002, 1004, 1008, 1010, 1012) the resonators being operable to provide radio frequency resonances in at least two different operational frequency bands (VHF, UHF, 700/800 MHz, GPS ranges) the wires being mutually adjacent and at least three of the wires having different lengths, and a plurality of radio frequency feed channels (113, 115, 117, 119) each being operably connected to an associated one of the resonators to deliver an RF signal between that resonator and an associated radio.
Abstract:
A terminal (200) and method for operation thereof for use in a wireless communication system (100), the terminal including a plurality of antennas (215, 235, 255) and a plurality of receiver chains (217, 237, 257) each including an associated one of the antennas, the terminal being operable to receive a signal including a plurality of time divided portions including a first portion (303) and a second portion (304), characterised in that the terminal is operable in a manner such each of the plurality of receiver chains is active when the first portion of the signal is being received and at least one of the receiver chains is inactive when the second portion of the signal is being received.
Abstract:
A wireless communication unit includes a linearised transmitter having a forward path and a feedback path, respectively comprising at least one up-mixer and down-mixer, and forming two loops in quadrature. A phase training signal is applied to the at least one down-mixer in the feedback path in an open loop mode of operation to identify a loop phase adjustment to be applied. At least one of the two loops is switched to a closed loop mode of operation and the loop phase adjustment is applied to at least one up-mixer located in the forward path.
Abstract:
The power supply voltage Vs for the power amplifier 126 in a radio transmitter is reduced until non-linearity is detected, thereby achieving optimal amplifier efficiency. The supply voltage controller 127 provides a reference signal to the regulator 111 which is the product of the RF signal envelope and a scaling factor from the nonlinearity detector 125. The scaling factor is reduced until nonlinearity occurs or the scaling factor reaches a minimum value. The nonlinearity detector 125 (figure 2) is coupled to the outputs of the Cartesian loop filters 116,118 and measures the ratio of power at an offset frequency to on-channel power. Efficiency is not reduced by VSWR changes.
Abstract:
A wireless communication unit (300) comprises a linearised transmitter (325) having a forward path and a feedback path, respectively comprising at least one up- mixer and down-mixer, and forming two loops in quadrature. A phase training signal is applied to the at least one down-mixer in the feedback path in an open loop mode of operation to identify a loop phase adjustment to be applied. At least one of the two loops is switched to a closed loop mode of operation and the loop phase adjustment is applied to at least one up-mixer located in the forward path.