Abstract: An apparatus and a method include receiving, by a transmitter integrated circuit (IC) having a serial data communications interface, a digital transmit signal, and generating a first signal that is an analog radio frequency (RF) modulated signal based on the digital transmit signal and a second signal that is a phase-offset version of the first signal. An amplified signal is generated by amplifying the first signal and includes an amplified version of the first signal and an out-of-band distortion signal. A reduced-power signal is generated from the amplified signal. The reduced-power signal is subtracted from the second signal to output a distortion cancellation signal. An amplified distortion cancellation signal is generated by amplifying the distortion cancellation signal using an error amplifier. The amplified distortion cancellation signal and a delayed version of the amplified signal are combined to output an amplified version of the first signal with reduced distortion.

Abstract: A tuneable filter comprising at least one resonator body comprising a resonant cavity defined by an electrically conducting cavity wall, the cavity wall comprising a grounding face, a capacitive face and a surrounding wall extending therebetween; a resonator within the cavity; and, a detuning arm arranged within the cavity substantially parallel to the capacitive face, the detuning arm being adapted to rotate in a plane substantially parallel to the capacitive face about a detuning axis.

Abstract: An electrical filter for filtering an electrical signal, the filter having a transmission characteristic comprising a band edge at a band edge transition frequency, the filter comprising a circulator having a first circulator port for receiving a signal to be filtered, the circulator being adapted to transfer a signal received at the first circulator port to a second circulator port and being further adapted to transfer a signal received at the second circulator port to a third circulator port; and, a reflection mode filter connected to the second port; the reflection mode filter comprising a filter network comprising at least one resonator, the filter network having a network input connected to the second circulator port; and, a further resonator connected to the network input, the further resonator being arranged to provide an extracted pole providing a transmission zero closest to the band edge transition frequency; wherein the further resonator has a high Q compared to the low Q of at least one of the at

Abstract: A tuneable filter comprising at least one resonator body comprising a resonant cavity defined by an electrically conducting cavity wall, the cavity wall comprising a grounding face, a capacitive face and a surrounding wall extending therebetween; a resonator within the cavity; and, a detuning arm arranged within the cavity substantially parallel to the capacitive face, the detuning arm being adapted to rotate in a plane substantially parallel to the capacitive face about a detuning axis.

Abstract: An electrical filter for filtering an electrical signal, the filter having a transmission characteristic comprising a band edge at a band edge transition frequency, the filter comprising a circulator having a first circulator port for receiving a signal to be filtered, the circulator being adapted to transfer a signal received at the first circulator port to a second circulator port and being further adapted to transfer a signal received at the second circulator port to a third circulator port; and, a reflection mode filter connected to the second port; the reflection mode filter comprising a filter network comprising at least one resonator, the filter network having a network input connected to the second circulator port; and, a further resonator connected to the network input, the further resonator being arranged to provide an extracted pole providing a transmission zero closest to the band edge transition frequency; wherein the further resonator has a high Q compared to the low Q of at least one of the at

Abstract: A TEM mode resonator includes a tuneable cavity defined by an electrically conducting cavity wall. The cavity wall includes a grounding face, a capacitor face and a surrounding wall extending therebetween. An electrically conducting resonator member is disposed within the cavity and extends from the grounding face part way towards the capacitor face. A portion of the resonator member proximate to the capacitor face includes a recess defining an aperture. A tuning mechanism disposed outside the tuneable cavity, includes a tuning arm extending into the tuneable cavity through the aperture. The tuning mechanism is adapted to displace the tuning arm towards and away from the capacitor face. At least a portion of the tuning arm disposed within the cavity is the tuning element, which is formed of either a metal or a dielectric.

Abstract: A Doherty amplifier is described which comprises: a power splitter (120) having a first output and a second output, wherein the first output is connected to a main power splitter (392) having first and second outputs which differ in phase by 90°; and the second output is connected to an auxiliary power splitter (342) having first and second outputs which differ in phase by 90°; a main final stage amplifier (234) comprising first (324) and second (325) main paired amplifiers, the inputs of which are connected to the first and second outputs of the main power splitter (352); an auxiliary final stage amplifier (244) comprising first (344) and second auxiliary (345) paired amplifiers, the inputs of which are connected to the first and second outputs of the auxiliary power splitter (342); wherein the output from the first main paired amplifier (334) is connected to the output from the first auxiliary paired amplifier (344) by an impedance inverter (250); and the output from the second main paired amplifier (345) i