Abstract: Systems and techniques are described for applying a polar bias modulation having a phase component and an amplitude component to a signal amplified by a power amplifier. The power amplifier (PA) has a plurality of amplifier gain stages and is configured to amplify an input to create an amplifier output signal. The input to the power amplitude is phase modulated based upon the phase component of the polar bias modulation, but need not be amplitude modulated. Amplitude modulation is provided by logic that includes a detector configured to receive an indication of the amplifier output as a feedback signal, a control module configured to generate a control signal based upon both the feedback signal and the amplitude component of the polar bias modulation, and a bias circuit configured to adjust a bias signal associated with at least one of the plurality of amplifier gain stages in response to the control signal.

Abstract: A multi-mode transmitter architecture is configurable for multiple modulation modes using either polar or polar-lite modulation. Multiplexed signal paths and reconfigurable components are controlled for performance in GMSK and EDGE burst modes. Polar-lite EDGE modulation is programmed by setting a multiplexer coupling a first amplitude modulated signal path with a frequency modulated signal path input to a dual-mode power amplifier for amplification of the combined EDGE transmission signal. In full-polar EDGE modulation, amplitude modulated signal is multiplexed into a second amplitude modulated signal path for A/D conversion and comparison with a polar feedback signal coupled from the power amplifier output. The resulting comparison is applied to a power control port of the power amplifier to amplitude modulate the EDGE transmission output. Multiplexers are configured to disconnect the amplitude modulated paths when operating in GMSK signaling for both full-polar and polar-lite modulation.

Abstract: Systems and techniques are described for applying a polar bias modulation having a phase component and an amplitude component to a signal amplified by a power amplifier. The power amplifier (PA) has a plurality of amplifier gain stages and is configured to amplify an input to create an amplifier output signal. The input to the power amplitude is phase modulated based upon the phase component of the polar bias modulation, but need not be amplitude modulated. Amplitude modulation is provided by logic that includes a detector configured to receive an indication of the amplifier output as a feedback signal, a control module configured to generate a control signal based upon both the feedback signal and the amplitude component of the polar bias modulation, and a bias circuit configured to adjust a bias signal associated with at least one of the plurality of amplifier gain stages in response to the control signal.

Abstract: Method and apparatus are provided for protecting radio frequency (RF) power amplifiers. A circuit (10) is provided for limiting a supply current to a first stage (Q3) of the RF power amplifier having a second stage (Q2) coupled to the first stage. The circuit comprises a comparator (14) having first and second inputs and an output, and a switching circuit (12, 20, 22, 24) having an input coupled to the output of the comparator (14) and having an output configured to couple to the first stage (Q3). The first input of the comparator (14) is configured to receive the supply current, and the second input is configured to receive a current supplied to the second stage (Q2). The comparator (14) is configured to compare a ratio of the supply current to the first stage to the current supplied to the second stage (Q2) with a predetermined value. The switching circuit (12, 20, 22, 24) is configured to limit the supply current to the first stage (Q3) when the ratio exceeds the predetermined value.

Abstract: A cross-coupled cascode voltage controlled oscillator including a variable-frequency tank circuit, first and second cascode-coupled active devices coupled to the tank circuit, and third and fourth cascode-coupled active devices coupled to the tank circuit, the first and second active devices being cross-coupled to the third and fourth active devices. The invention produces lower drain the gate voltages resulting in fewer device failures.

Abstract: Systems and methods are described for a band switchable voltage controlled oscillator. A method comprises: operating said voltage controlled oscillator in a first frequency band by switching a first capacitive circuit having a capacitance that varies with a tuning voltage; and operating said voltage controlled oscillator in a second frequency band by switching a second capacitive circuit having a capacitance that does not vary with the tuning voltage.

Abstract: A multiple frequency band receiver (102) receives at least two frequency bands that are close but not adjacent. A first bandpass filter (304) passes signals in the first frequency band. A second bandpass filter (306) passes signals in the second frequency band. The first and second filters each attenuate signals between the first and second frequency band to at least a first level so as to provide selectivity in the frequency range between the first and second frequencies to prevent the signals between these frequency bands from being further processed by the communication device. A third filter (322) coupled to first and second filters passes signals in both the first and second frequency band and attenuates signals above the pass band of the higher of the first and second filters and below the lower of the first and second filters.

Abstract: According to the apparatus of the present disclosure, dual gate control and dual gain control uses variable voltages on the gates of first stage (302) and a second stage (304) to control the output power. In alternate embodiments, dual drain control is also employed using a variable voltage supply on the drains of the first stage (302) and the second stage (304). In particular, a level shifter circuit (421) is employed to convert a positive voltage gate control signal to negative voltage with respect to ground. Drain current limiting circuits (417, 419) are used to sample drain currents and generate gate voltages to maintain a desired current ratio between stages of a multi-stage amplifier. When dual drain control is also employed, a 1:1 ratio of drain control voltages is employed at low power levels, with a single drain control at higher power levels.

Abstract: A combline stripline filter includes a number of conductive strips, each connected to ground on one end and capacitively loaded to ground at the other end. Input and output pads will make a surface mountable connection to a printed circuit board. Tuning is provided for by removing ground over the extension ends of the outside resonators. The center resonators are tuned by removing metal from areas on the cover that are connected to the resonators by plated through holes. Undesired capacitance is compensated for by rounding the ends of the resonators and the opposing ground planes.

Abstract: A three way oscillator signal power splitting circuit splits power provided at the output of a voltage controlled oscillator (VCO). The circuit is implemented on a printed circuit board section having a first layer which includes a first conductor for receiving the power from the VCO, a second layer having a second conductor, substantially parallel to and adjacent the first conductor, for receiving a portion of the power on the first main conductor via broadside coupling, and a third conductor, situated substantially parallel to and adjacent the first and second conductors, for receiving a portion of the power on the first main conductor also via broadside coupling. A ground conductor is additionally included on the third layer for providing a ground reference for the first, second and third conductors, and resistors are used to terminate the second and third conductors.