Abstract: A system including a phase comparator to compare a first signal and a second signal to generate a phase error signal, and a controller to generate an adjusted phase error signal from the phase error signal in response to an amplitude of at least one of the first signal and the second signal.

Abstract: A system including a phase comparator to compare a first signal and a second signal to generate a phase error signal, and a controller to generate an adjusted phase error signal from the phase error signal in response to an amplitude of at least one of the first signal and the second signal.

Abstract: A power amplifier controller circuit controls a power amplifier based upon an amplitude correction signal indicating the amplitude difference between the amplitude of the input signal and an attenuated amplitude of the output signal. The power amplifier controller circuit comprises an amplitude control loop and a phase control loop. The amplitude control loop adjusts the supply voltage to the power amplifier based upon the amplitude correction signal. The amplitude control loop may also compensate for impedance mismatch with the load by increasing the power delivered from the power amplifier to the load, or decrease the output power of the power amplifier upon detection of excessive power dissipation in the power amplifier. The phase control loop adjusts the phase of the input signal based upon a phase error signal indicating a phase difference between phases of the input signal and the output signal to reduce phase distortion generated by the power amplifier.

Abstract: A power amplifier controller measures the distortion of a power amplifier output. Based upon the distortion measured, the supply voltage to the PA is adjusted in a control loop. In one embodiment, distortion is measured by computing the ratio of the measured power in the output frequencies outside the desired output channel to the measured power in the output frequencies within the desired channel. If the distortion measured from the PA is higher than a target distortion level, the power supply voltage is raised. If the distortion measured from the PA is lower than the target distortion level, the power supply voltage is reduced. Thus, the supply voltage to the PA is maintained at the lowest possible voltage level, improving the efficiency of the PA.

Abstract: A radio frequency (RF) power amplifier system is provided, in which a distortion of the RF output signal from the power amplifier is estimated by comparing the RF output signal with reference modulation information. The supply voltage to the power amplifier is adjusted so that the estimated distortion of the RF output signal corresponds to a predetermined distortion level. The predetermined distortion level is set to represent an acceptable distortion level at the RF output signal.

Abstract: A power amplifier controller controls a power amplifier and is coupled to a polar modulator. The polar modulator generates an amplitude component and a phase-modulated component of the desired RF modulated signal, and outputs to the power amplifier controller. The power amplifier controller regenerates a combined phase and amplitude modulated RF signal to generate an input signal to a power amplifier by adjusting the gain of a VGA based on the amplitude component of the desired RF modulated signal. Concurrently, the power amplifier controller both controls an adjusted supply voltage to the PA and adjusts the gain of the VGA based upon an amplitude correction signal or amplitude error signal.

Abstract: A power amplifier controller for adjusting a supply voltage to a power amplifier. The power amplifier controller adjusts the supply voltage so that distortion in an RF output signal corresponds to a predetermined limit. An amplitude error signal is generated by the power amplifier controller which represents a difference between an RF output signal and an attenuated RF output signal. The AC components of the amplitude error signal are processed to generate a deviation signal that represents the distortion in the RF output signal. The supply voltage to the power amplifier is increased when the deviation signal exceeds a distortion level control signal, and decreased when the deviation signal drops below the distortion level control signal.

Abstract: A power supply system comprises a low-speed power supply and a high-speed power supply configured to operate in first and second frequency ranges, respectively, and generate first and second outputs, respectively. The lower end of the second frequency range is at least higher than a lower end of the first frequency range. A frequency blocking power combiner circuit combines the power from the first output with the power from the second output to generate a combined, third output for driving a load, while providing frequency-selective isolation between the first and second outputs. A feedback circuit is coupled to receive the combined, third output through a global feedback loop. The feedback circuit generates first and second power supply control signals for controlling the low-speed power supply and the high-speed power supply, respectively, based on a difference between the third output and the predetermined control signal.

Abstract: A power amplifier controller measures the distortion of a power amplifier output. Based upon the distortion measured, the supply voltage to the PA is adjusted in a control loop. In one embodiment, distortion is measured by computing the ratio of the measured power in the output frequencies outside the desired output channel to the measured power in the output frequencies within the desired channel. If the distortion measured from the PA is higher than a target distortion level, the power supply voltage is raised. If the distortion measured from the PA is lower than the target distortion level, the power supply voltage is reduced. Thus, the supply voltage to the PA is maintained at the lowest possible voltage level, improving the efficiency of the PA.

Abstract: A power amplifier controller for adjusting a supply voltage to a power amplifier. The power amplifier controller adjusts the supply voltage so that distortion in an RF output signal corresponds to a predetermined limit. An amplitude error signal is generated by the power amplifier controller which represents a difference between an RF output signal and an attenuated RF output signal. The AC components of the amplitude error signal are processed to generate a deviation signal that represents the distortion in the RF output signal. The supply voltage to the power amplifier is increased when the deviation signal exceeds a distortion level control signal, and decreased when the deviation signal drops below the distortion level control signal.

Abstract: A power amplifier controller for adjusting a supply voltage to a power amplifier. The power amplifier controller adjusts the supply voltage so that distortion in an RF output signal corresponds to a predetermined limit. An amplitude error signal is generated by the power amplifier controller which represents a difference between an RF output signal and an attenuated RF output signal. The AC components of the amplitude error signal are processed to generate a deviation signal that represents the distortion in the RF output signal. The supply voltage to the power amplifier is increased when the deviation signal exceeds a distortion level control signal, and decreased when the deviation signal drops below the distortion level control signal.

Abstract: A power supply system comprises a low-speed power supply and a high-speed power supply configured to operate in first and second frequency ranges, respectively, and generate first and second outputs, respectively. The lower end of the second frequency range is at least higher than a lower end of the first frequency range. A frequency blocking power combiner circuit combines the power from the first output with the power from the second output to generate a combined, third output for driving a load, while providing frequency-selective isolation between the first and second outputs. A feedback circuit is coupled to receive the combined, third output through a global feedback loop. The feedback circuit generates first and second power supply control signals for controlling the low-speed power supply and the high-speed power supply, respectively, based on a difference between the third output and the predetermined control signal.

Abstract: A power supply system comprises a low-speed power supply and a high-speed power supply configured to operate in first and second frequency ranges, respectively, and generate first and second outputs, respectively. The lower end of the second frequency range is at least higher than a lower end of the first frequency range. A frequency blocking power combiner circuit combines the power from the first output with the power from the second output to generate a combined, third output for driving a load, while providing frequency-selective isolation between the first and second outputs. A feedback circuit is coupled to receive the combined, third output through a global feedback loop. The feedback circuit generates first and second power supply control signals for controlling the low-speed power supply and the high-speed power supply, respectively, based on a difference between the third output and the predetermined control signal.

Abstract: A system including a phase comparator to compare a first signal and a second signal to generate a phase error signal, and a controller to generate an adjusted phase error signal from the phase error signal in response to an amplitude of at least one of the first signal and the second signal.

Abstract: A power amplifier controller circuit controls a power amplifier based upon an amplitude correction signal indicating the amplitude difference between the amplitude of the input signal and an attenuated amplitude of the output signal. The power amplifier controller circuit comprises an amplitude control loop and a phase control loop. The amplitude control loop adjusts the supply voltage to the power amplifier based upon the amplitude correction signal. The RF power amplifier system may reduce the corrective action of the amplitude loop during periods of relatively rapid changes in amplitude, and thus distortion can be further reduced.

Abstract: A power amplifier controller circuit controls a power amplifier based upon an amplitude correction signal indicating the amplitude difference between the amplitude of the input signal and an attenuated amplitude of the output signal. The power amplifier controller circuit comprises an amplitude control loop and a phase control loop. The amplitude control loop adjusts the supply voltage to the power amplifier based upon the amplitude correction signal. The amplitude control loop may also compensate for impedance mismatch with the load by increasing the power delivered from the power amplifier to the load, or decrease the output power of the power amplifier upon detection of excessive power dissipation in the power amplifier. The phase control loop adjusts the phase of the input signal based upon a phase error signal indicating a phase difference between phases of the input signal and the output signal to reduce phase distortion generated by the power amplifier.

Abstract: The present invention discloses a method and apparatus for correcting the DC offset caused by self-conversion of the oscillator signal in an RF-to-baseband converter. The circuit comprises: a subtractor for subtracting an amplified DC offset signal from a filtered mixer signal to generate a corrected signal; a baseband amplifier coupled to the subtractor to receive the corrected signal to generate a baseband output signal; a low-pass filter coupled to the baseband amplifier to generate a DC offset signal representative of the DC offset; and a DC offset amplifier coupled to the low-pass filter and the subtractor to generate the amplified DC offset signal.

Abstract: A television receiver is provided including a first mixer having a first input adapted for receiving an input signal in a predetermined frequency range. It should be noted that the input signal may take the form of either a broadcast television signal, a cable television signal, or a digital signal transmitted over a cable delivery system. The first mixer further includes a second input adapted for receiving a first reference signal having a first operating frequency. In use, the first mixer is suitable for outputting an intermediate frequency signal having a frequency greater than at least one frequency in the predetermined frequency range. Also included is a filter for filtering the intermediate frequency signal. A phase shifting network is provided which includes an input adapted for receiving a second reference signal having a second operating frequency. The phase shifting network further includes a pair of outputs.

Abstract: A converter for the direct down-conversion of direct broadcast satellite signals such as those used for digital television. The direct broadcast satellite signal received from the satellite dish is amplified and then downshifted within the Low Noise Block (LNB), a subsystem contained with the satellite dish assembly, to a predetermined frequency band, typically in the L-band in the range 950 MHz to 2150 MHz. The signal is then sent via a coaxial cable to the set-top box unit located indoors, and there directly converted from the received frequency to baseband, in one embodiment by a single integrated circuit comprising a variable gain amplifier (VGA), frequency synthesizer, a quadrature generator and a plurality of mixers.

Abstract: A converter for the direct down-conversion of direct broadcast satellite signals such as those used for digital television. The direct broadcast satellite signal received from the satellite dish is amplified and then downshifted within the Low Noise Block (LNB), a subsystem contained with the satellite dish assembly, to a predetermined frequency band, typically in the L-band in the range 950 MHz to 2150 MHz. The signal is then sent via a coaxial cable to the set-top box unit located indoors, and there directly converted from the received frequency to baseband, in one embodiment by a single integrated circuit comprising a variable gain amplifier (VGA), frequency synthesizer, a quadrature generator and a plurality of mixers.