Abstract: A digital predistortion (DPD) verification and transmitter nonlinearity estimation system includes a transmitter path including one or more power amplifiers (PAs) coupled to an upconversion mixer. A digital tone generator circuit generates a single-tone radio-frequency (RF) signal that is applied to a first input of the upconversion mixer to generate a dual-tone RF signal, where a second input of the upconversion mixer is disabled. A downconversion mixer downconverts an amplified dual-tone RF signal to generate an intermediate-frequency (IF) dual-tone signal. A processing block analyzes the IF dual-tone signal to estimate signal strengths of one or more intermodulation (IM) product signals.

Abstract: Apparatus and methods for transmit power control in wireless communication systems are provided. In one aspect, a wireless communication system includes a transmit chain that generates a transmit signal based on a data signal having a time-varying signal envelope, a power amplifier that amplifies the transmit signal, and a transmit chain controller that generates a first power control signal and a second power control signal that control an adjustable power level of the transmit chain. The transmit chain controller includes an error extractor that generates an error signal based on comparing an output signal power of the power amplifier to the time-varying signal envelope. The transmit chain controller further includes a control signal generator that generates the first power control signal and an adjustment signal based on estimating the error signal, and that generates the second power control signal based on the error signal and the adjustment signal.

Abstract: The present disclosure is directed to an envelope tracking supply modulator for multiple PAs. The envelope tracking supply modulator is configured to provide, for each of the multiple PAs, a separate supply voltage that is modulated based on the envelope of the respective RF input signal to the PA. Each of the modulated supply voltages is constructed from a DC component and an alternating current (AC) component. The DC component for each modulated supply voltage is generated by a main switching regulator that is shared by the multiple PAs. In one embodiment, the AC component for each modulated supply voltage is generated by an auxiliary switching regulator that is shared by the multiple PAs and a separate linear regulator for each of the multiple PAs. In another embodiment, the AC component for each modulated supply voltage is generated by a separate buffer.

Abstract: Apparatus and methods for transmit power control in wireless communication systems are provided. In one aspect, a wireless communication system includes a transmit chain that generates a transmit signal based on a data signal having a time-varying signal envelope, a power amplifier that amplifies the transmit signal, and a transmit chain controller that generates a first power control signal and a second power control signal that control an adjustable power level of the transmit chain. The transmit chain controller includes an error extractor that generates an error signal based on comparing an output signal power of the power amplifier to the time-varying signal envelope. The transmit chain controller further includes a control signal generator that generates the first power control signal and an adjustment signal based on estimating the error signal, and that generates the second power control signal based on the error signal and the adjustment signal.

Abstract: Apparatus and methods for power control in mobile communication devices are provided. In one aspect, a wireless communication device includes a transmit chain that receives a digital in-phase (I) signal and a digital quadrature-phase (Q) signal and that generates a transmit signal. The wireless communication device further includes a power amplifier that amplifies the transmit signal, and a transmit chain controller including a reference generator that combines the digital I signal and the digital Q signal and generates a reference signal corresponding to an instantaneous value of an envelope of the combined signal. The transmit chain controller further includes an error extractor that generates an error signal based on the reference signal and an output power of the power amplifier, and a control signal generator that uses the error signal to generate one or more power control signals for controlling an adjustable power level of the transmit chain.

Abstract: Apparatus and methods for power control in mobile communication devices are provided. In one aspect, a wireless communication device includes a transmit chain that receives a digital in-phase (I) signal and a digital quadrature-phase (Q) signal and that generates a transmit signal. The wireless communication device further includes a power amplifier that amplifies the transmit signal, and a transmit chain controller including a reference generator that combines the digital I signal and the digital Q signal and generates a reference signal corresponding to an instantaneous value of an envelope of the combined signal. The transmit chain controller further includes an error extractor that generates an error signal based on the reference signal and an output power of the power amplifier, and a control signal generator that uses the error signal to generate one or more power control signals for controlling an adjustable power level of the transmit chain.

Abstract: A method and apparatus is provided to improve upon the efficiency of a power amplifier. Suitable hardware/software in the form of circuitry, logic gates, and/or code functions to construct an envelope tracking waveform of an input communications signal and modulate the input supply voltage based on power amplifier circuitry operational parameters such as slew rates.

Abstract: A method for an antenna mismatch compensation may include determining an amplitude ratio by measuring a ratio of amplitudes of a reflected signal and an incident signal of an antenna tuning circuit coupled to an antenna. A time difference between the reflected signal and the incident signal may be measured. The time difference may be converted to a phase difference. A topology and one or more parameters of the antenna tuning circuit may be determined based on the amplitude ratio and the phase difference so that the antenna tuning circuit compensates for the antenna mismatch.

Abstract: Apparatus and methods for power control in mobile communication devices are provided. In one aspect, a method for accurately controlling an adjustable power level of a data signal in a transmit chain of a transmitter is provided. The method includes adjusting a controllable gain level of a digital-to-analog converter based on a desired peak-to-average ratio of a transmit signal envelope, adjusting a digitally controlled discrete gain-step amplifier, the amount of gain per step based on an initial estimate of the transmitter gain and a target power, applying a factor to a gain adjuster responsive to the gain step change in the transmit chain, and repeating the adjusting and applying steps until a feedback signal level exceeds a reference signal level.

Abstract: Various configurations and arrangements of systems and methods for compensating for variations in VCO output frequencies are described. A system in accordance with the disclosure can include an oscillator circuit including an oscillator, a first variable capacitance diode coupled to the oscillator and a second variable capacitance diode coupled to the oscillator. The system further includes a voltage source configured to apply a first voltage to the oscillator circuit to cause the output signal to comprise a selected frequency, the selected frequency being based on a received reference voltage. The system further includes a controller circuit configured to compare an operating voltage of the oscillator to the reference voltage while the first voltage is applied to the oscillator; and apply a second voltage to the oscillator circuit based on the comparison. The second voltage compensates for a difference between the reference voltage and the first voltage.

Abstract: A method and apparatus is provided to improve upon the efficiency of a power amplifier. Suitable hardware/software in the form of circuitry, logic gates, and/or code functions to construct an envelope tracking waveform of an input communications signal and modulate the input supply voltage based on power amplifier circuitry operational parameters such as slew rates.

Abstract: A method to control adjustable power levels uses a network of attenuators that includes a fixed attenuation and a variable attenuation. The method adjusts the variable attenuation to approach the fixed attenuation, provides gain to an attenuated signal in an amount proximate to the fixed attenuation to generate a compensated signal, and compares power levels of a non-attenuated signal and the compensated signal to generate a first error signal. The method introduces the fixed attenuation and correspondingly reduces the variable attenuation to maintain a combined attenuation. The combined attenuation generates a modified compensated signal. The method measures a difference between the first power levels of the non-attenuated signal and the modified compensated signal to generate a second error signal, and generates a control signal as function of the first and second error signals to adjust the variable attenuation to reduce an attenuation mismatch introduced between the fixed and variable attenuations.

Abstract: Apparatus and methods for power control in mobile communication devices are provided. In one aspect, a method for accurately controlling an adjustable power level of a data signal in a transmit chain of a transmitter is provided. The method includes adjusting a controllable gain level of a digital-to-analog converter based on a desired peak-to-average ratio of a transmit signal envelope, adjusting a digitally controlled discrete gain-step amplifier, the amount of gain per step based on an initial estimate of the transmitter gain and a target power, applying a factor to a gain adjuster responsive to the gain step change in the transmit chain, and repeating the adjusting and applying steps until a feedback signal level exceeds a reference signal level.

Abstract: Various configurations and arrangements of systems and methods for compensating for variations in VCO output frequencies are described. A system in accordance with the disclosure can include an oscillator circuit including an oscillator, a first variable capacitance diode coupled to the oscillator and a second variable capacitance diode coupled to the oscillator. The system further includes a voltage source configured to apply a first voltage to the oscillator circuit to cause the output signal to comprise a selected frequency, the selected frequency being based on a received reference voltage. The system further includes a controller circuit configured to compare an operating voltage of the oscillator to the reference voltage while the first voltage is applied to the oscillator; and apply a second voltage to the oscillator circuit based on the comparison. The second voltage compensates for a difference between the reference voltage and the first voltage.

Abstract: Average Power Tracking (APT) is a technique that can be utilized for vary the supply voltage to a power amplifier (PA) on a timeslot basis in order to reduce power consumption of the PA. Systems and methods are provided for maximizing power savings associated with the PA by utilizing APT in a continuous and aggressive manner. Additionally, the systems and methods can further compensate for variations in temperature, frequency, antenna load, and peak to average power ratio (PAPR) without sacrificing the power savings.

Abstract: Embodiments provide improved systems and methods of gain control and calibration for wireless transmitters. In particular, embodiments allow linear gain control over the entire transmitter gain control range, independent of temperature/process variations. Embodiments require very low power consumption compared to existing approaches. Embodiments may also be used for gain control calibration during production time, thereby substantially reducing production calibration time and cost.

Abstract: A transmitter adjusts a transmitted power level by modifying a control input of a variable gain amplifier. A power amplifier control system includes an envelope extractor, an error extractor, and a feed-forward multiplier. The envelope extractor receives data signal inputs and computes the envelope of the combined signal. The error extractor generates an error signal as a function of the combined signal and the output power generated by the power amplifier. The feed-forward multiplier generates a modified error signal that is responsive to a function of the gain in a feedback path. A corresponding method for controlling a power level is also disclosed. In some embodiments, a transmit chain with a power control loop is used to adjust the transmit signal power applied at an input of a variable gain amplifier. A corresponding method for adjusting the transmit signal power level is also included.

Abstract: A method for an antenna mismatch compensation may include determining an amplitude ratio by measuring a ratio of amplitudes of a reflected signal and an incident signal of an antenna tuning circuit coupled to an antenna. A time difference between the reflected signal and the incident signal may be measured. The time difference may be converted to a phase difference. A topology and one or more parameters of the antenna tuning circuit may be determined based on the amplitude ratio and the phase difference so that the antenna tuning circuit compensates for the antenna mismatch.

Abstract: A method to control adjustable power levels uses a network of attenuators that includes a fixed attenuation and a variable attenuation. The method adjusts the variable attenuation to approach the fixed attenuation, provides gain to an attenuated signal in an amount proximate to the fixed attenuation to generate a compensated signal, and compares power levels of a non-attenuated signal and the compensated signal to generate a first error signal. The method introduces the fixed attenuation and correspondingly reduces the variable attenuation to maintain a combined attenuation. The combined attenuation generates a modified compensated signal. The method measures a difference between the first power levels of the non-attenuated signal and the modified compensated signal to generate a second error signal, and generates a control signal as function of the first and second error signals to adjust the variable attenuation to reduce an attenuation mismatch introduced between the fixed and variable attenuations.

Abstract: Systems and methods are provided for detecting forward power sent to an antenna and reflected power reflected back from the antenna. Embodiments of the present invention provide systems and methods for measuring forward and reflected power and controlling the amount of power supplied to the antenna responsive to these measurements. Embodiments of the present invention enable the power sent to the antenna to be dynamically altered when antenna impendence changes (e.g., when the antenna gets too close to another object).