Abstract:
A system for saturation detection, correction and recovery in a power amplifier includes a power amplifier, a closed power control loop configured to develop a power control signal (VPC), and power control circuitry configured to reduce the power control signal if the power amplifier is operating in a saturation mode.
Abstract:
A system for generating local oscillator (LO) signals for a quadrature mixer includes an oscillator configured to provide a reference frequency signal, at least one frequency divider configured to divide the reference frequency signal into three offset phase signals, a first summing circuit configured to generate two nominal 90 degree offset phase signals from the three offset phase signals, and a second summing circuit configured to generate at least two amplitude-corrected 90 degree offset-phase quadrature signals.
Abstract:
A system for transmitting and receiving data is provided. The system includes a direct-conversion receiver that receives a signal modulated on a carrier frequency signal. The direct-conversion receiver includes one or more subharmonic local oscillator mixers. A local oscillator is connected to the direct conversion receiver, and generates a signal having a frequency equal to a subharmonic of the carrier frequency signal. A transmitter is connected to the local oscillator, which uses the local oscillator signal to transmit outgoing data.
Abstract:
A software defined transmit architecture includes a plurality of individually selectable components that can be selectively enabled to transmit a data signal that complies with any of a plurality of transmission standards. The software defined transmit architecture comprises components that can be enabled by associated logic to transmit, for example, communications signals that comply with the global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), which employs TDMA, and wide band code division multiple access (WCDMA) transmission standards. A single transmit architecture supports multiple transmission standards, thus minimizing the number of components in a multi-band, multi-mode portable transceiver, while reducing the number of active components.
Abstract:
A supply voltage controlled power amplifier includes a power amplifier, a closed power control loop configured to generate a power control signal, and a voltage regulator coupled to the power control loop, the voltage regulator including a first regulator stage, a second regulator stage, and a peak detector, wherein an output of the second regulator stage is applied as a feedback signal to the first regulator stage and wherein an output of the first regulator stage is decreased to a level consistent with an output of the power amplifier and an additional operating buffer amount.
Abstract:
A system for saturation detection, correction and recovery in a power amplifier includes a power amplifier, a closed power control loop configured to develop a power control signal (VPC), and power control circuitry configured to reduce the power control signal if the power amplifier is operating in a saturation mode.
Abstract:
A system for generating local oscillator (LO) signals for a quadrature mixer includes an oscillator configured to provide a reference frequency signal, at least one frequency divider configured to divide the reference frequency signal into three offset phase signals, a first summing circuit configured to generate two nominal 90 degree offset phase signals from the three offset phase signals, and a second summing circuit configured to generate at least two amplitude-corrected 90 degree offset-phase quadrature signals.
Abstract:
A system for a fast, closed power control loop that quickly adjusts the output power of a power amplifier in a non-constant amplitude modulation format. Embodiments of the invention allow fast and precise closed loop power control in a communication system that has a transmit signal that includes a phase modulated component and an amplitude modulated signal component. By detecting the level of the transmit signal before and after the power amplifier, the invention ignores changes in the amplitude of the transmit signal, resulting in an accurate measure of the power amplifier gain. The difference between the level of the transmit signal before and after the power amplifier provides a signal that represents the gain of the power amplifier. The gain signal is compared with a reference signal to develop an error signal. The error signal is used to control the output of the power amplifier.
Abstract:
A low noise mixer comprises a first mixer core configured to receive a radio frequency (RF) input signal having an RF frequency, and a first local oscillator signal, wherein the first local oscillator signal is at a frequency that is nominally twice the frequency of the RF frequency, the first mixer core configured to switch the RF input signal to at least one secondary mixer core at a frequency that coincides with the frequency of the first local oscillator signal, the at least one secondary mixer core configured to receive the switched RF input signal and a second local oscillator signal, where the second local oscillator signal is at the same nominal frequency as the RF input signal, and wherein switching the RF input signal at the frequency of the first local oscillator signal substantially eliminates flicker noise associated with the down-conversion process.
Abstract:
A method for a closed power control feedback loop allows a single portable transceiver architecture to be used for systems in which a transmit signal including both a phase modulated (PM) component and an amplitude modulated (AM) component are supplied to a power amplifier and in systems in which the transmit signal has only a PM component supplied to a power amplifier. By injecting the inverse of the AM portion of the desired transmit signal into the closed power control feedback loop, the feedback loop will not cancel the AM portion of the signal, thus allowing a system where both a PM component and an AM component of the transmit signal are present at the output of the power amplifier to function using a closed power control feedback loop.