Motorola Corporation

Robert Michael Jackson

Bernard Eugene Sigmon

Ronald Gene Myers

Pallab Midya

Dale Robert Anderson

A method and apparatus for efficient power amplification over a wide dynamic range and for a number of modulation formats includes a carrier amplifier (30) and a peaking amplifier (40). The carrier amplifier (30) operates with a bias generated by an envelope amplifier (80) which amplifies the envelope of an input signal as generated by an envelope detector (70). The peaking amplifier (40) operates with a fixed bias. The outputs of the carrier amplifier (30) and the peaking amplifier (40) are combined using an impedance transforming network (50). Envelope amplifier (80) can be turned on for high efficiency low power level operation, or it can be turned off for standard Doherty-type operation.

Method and apparatus for high efficiency power amplification

A method and apparatus for efficient power amplification of a modulated signal includes an envelope detector (220), an multi-output class S modulator (270), a driver amplifier (250), and a power amplifier (260). The multi-output class S modulator (270) amplifies the envelope of the input signal and generates a primary amplified envelope signal and at least one offset amplified envelope signal. The offset amplified envelope signal is used to modulate the driver amplifier (250), and the primary amplified envelope signal is used to modulate the power amplifier (260).

A method and apparatus for efficient power amplification with low distortion includes an envelope detector (220), a difference amplifier (130), an envelope amplifier (270), and a power amplifier (260). A feedback path is provided from the output through a second envelope detector (120) to the difference amplifier (130). The feedback circuit operates on the bandwidth of the envelope of the RF signal rather than at the RF bandwidth. An envelope amplifier (270) includes a difference amplifier (272), a pulsewidth modulator (275), a driver (280), switching transistors (285), a low pass filter (290), and a voltage scaler (292). A feedback path within the envelope amplifier reduces the time delay introduced by low pass filter (290). The combined feedback loops work together to reduce distortion and lower intermodulation products.

Method and apparatus for reducing distortion in a power amplifier

A method and apparatus for efficient power amplification with low phase distortion includes an envelope detector (30), a scaling amplifier (40), a driver amplifier (50), and a power amplifier (60). The scaling amplifier (40), in response to the envelope signal from the envelope detector (30), generates a bias signal which causes predistortion in the driver amplifier (50). The predistortion in the driver amplifier (50) compensates for phase distortion in the driver amplifier (50) and the power amplifier (60), resulting in low phase distortion output. An EER-type amplifier (200) with high efficiency utilizes the predistortion of a driver amplifier (250) to compensate for phase distortion in the driver amplifier (250) and a power amplifier (260).

Method and apparatus for compensation of phase distortion in power

A method and apparatus for generating a modulated signal include a pulse modulation source (215), a pulse modulator (20) for modulating a pulsed signal, a high efficiency power amplifier (230) for amplifying the modulated pulsed signal, and a harmonic reduction filter (240) for passing the switching frequency of the pulsed signal as the RF carrier. The pulse modulation source (215) accepts baseband inphase and quadrature signals and determines phase values and duty ratios for modulating the pulsed signal. The pulse modulator (20) phase modulates and duty cycle modulates the pulsed signal before it is amplified and filtered. A quadrature demodulator (260) produces baseband inphase and quadrature feedback signals for increased linearity.

Method and apparatus for generating a modulated signal

A Doherty-type active bias power amplifier (90) suitable for satellite telecommunication systems provides linear amplification of noise-like RF input signals (100) that have multiple carriers spread over a large instantaneous bandwidth. As RF input signal (100) to active bias power amplifier (90) increases, the negative pinch-off voltage that normally causes development of a negative voltage on the gate/base is precluded from occurring in the carrier amplifier (115) and thus an improvement in RF output power is achieved as well as an increase in the dynamic RF input drive range over which high efficiency operation can be achieved. Active biasing provides the proper bias-on point for the peaking amplifier (135) in order to achieve maximum RF efficiency operation.

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Gilbert, AZ, United States of America

Robert Michael Jackson