Abstract: A power correction module for use with an amplifier driving a load impedance is configured to sample the supply current and to cause a change in a control voltage, which corrects the supply voltage in response to a change in the load impedance. The supply voltage is corrected to cause the power amplifier to have a substantially constant output power. The power correction module is further configured to output a corrected peak voltage determined by an average value of the supply current.

Abstract: According to an exemplary embodiment, a transmitter system includes a power amplifier receiving a supply voltage and a supply current from a power control/current detection circuit, where the power amplifier drives a load impedance. The transmitter system further includes a power correction module configured to sample the supply current and to cause a change in a control voltage, which corrects the supply voltage in response to a change in the load impedance. The supply voltage is corrected to cause the power amplifier to have a substantially constant output power. The power correction module is further configured to output a corrected peak voltage determined by an average value of the supply current. The transmitter system further includes a predistortion module configured to determine the control voltage from a product of the corrected peak voltage and an amplitude modulation component and to output the control voltage to the power control/current detection circuit.

Abstract: A power correction module for use with an amplifier driving a load impedance is configured to sample the supply current and to cause a change in a control voltage, which corrects the supply voltage in response to a change in the load impedance. The supply voltage is corrected to cause the power amplifier to have a substantially constant output power. The power correction module is further configured to output a corrected peak voltage determined by an average value of the supply current.

Abstract: According to an exemplary embodiment, a transmitter system includes a power amplifier receiving a supply voltage and a supply current from a power control/current detection circuit, where the power amplifier drives a load impedance. The transmitter system further includes a power correction module configured to sample the supply current and to cause a change in a control voltage, which corrects the supply voltage in response to a change in the load impedance. The supply voltage is corrected to cause the power amplifier to have a substantially constant output power. The power correction module is further configured to output a corrected peak voltage determined by an average value of the supply current. The transmitter system further includes a predistortion module configured to determine the control voltage from a product of the corrected peak voltage and an amplitude modulation component and to output the control voltage to the power control/current detection circuit.

Abstract: A power control circuit for a power amplifier comprises a voltage regulator having a first input configured to receive a envelope control signal, a second input configured to receive a feedback signal, and a third input configured to receive a voltage clamp signal; and a clamp voltage reference circuit configured to generate the voltage clamp signal.

Abstract: A microtomographic system (10) for generating high-resolution, three dimensional images of a specimen (16) is disclosed. The microtomograph system includes an x-ray generator (12) that produces an x-ray beam (14), a specimen holder (18) that holds the specimen in the beam, and an x-ray detector (20) that measures the attenuation of the beam through the specimen. Two projections of each view of the specimen are made with this microtomographic system. Each projection is made with a different intensity x-ray beam. After the projections of one view of the specimen are made, the specimen is rotated on the specimen holder and another set of projections are made. The projections of each view of the specimen are analyzed together to provide a quantitative indication of the phase fraction of the material comprising the specimen. The projections of the different views are combined to provide a three-dimensional image of the specimen.

Abstract: The invention is an automatic, programmable video cassette player-changer in combination with a plurality of video cassette players which use video cassettes containing visual material for a television audience and a television monitor electrically coupled to each of the video cassette players. The video cassette player-changer includes a plurality of vertically stacked cassette trays which are adapted to contain the video cassettes and a support member adapted to maintain the vertically stacked cassette trays in a fixed position. The video cassette player-changer also includes a motor adapted so that it may be driven in two directions, a screw mechanically coupled to the motor so that it rotates in response to the motor, a coupling device which couples the rotating screw to the support member so the rotating screw raises and lowers the support member.