A transfer function generator provides the ability to provide a non-linear response in a feedback loop to compensate for non-linearities introduced elsewhere in the system. The transfer function generator includes a non-linear function generator configured to provide an output current that is a non-linear function of an input signal representing an error to be corrected. The transfer function generator can also include a linear function generator configure to provide a linear output current as a function of an input current representing the error corrected. Tuning devices can be provided to adjust the turn-on level of the non-linear function generator and the output level of the linear function generator to allow the transfer function generator flexibility in implementation.
RELATED APPLICATION
The present application is related to U.S. patent application Ser. No. 09/148,568, now U.S. Pat. No. 6,160,429 titled "A COMPACT CUBIC FUNCTION GENERATOR," which is of common assignee and was filed on Sep. 4, 1998, and which is incorporated herein by reference in its entirety.
A system and method for dynamically adjusting the operating bias of an RF transmitter amplifier in response to a power control signal. The invention provides high-efficiency RF power amplification for applications where the available power source is limited. The invention uses a power control signal resident in wireless communication system architectures with a detector and voltage to current converter to arrive at a dynamic amplifier operating bias.
A method and apparatus for improving loop stability and speed of a power control loop. Adjacent channel interference in the ramp-up and ramp-down (transient) of a TDMA burst is reduced. The present invention is used in a burst when the transient response and loop speed are important in the design of the control loop. The loop bandwidth variation resulting from linear conversion power detector and PIN diode RF attenuators in the loop is reduced by reducing the upper end of the loop bandwidth and increasing the lower end of the loop bandwidth. The upper limit of the loop bandwidth determines the loop stability and the lower limit of the loop bandwidth determines the minimum speed of the loop. A reference signal is sampled and processed to set a gain of a feedback loop in the power control loop. The setting of the gain of the feedback loop using the reference signal increases the lower loop bandwidth to increase a loop speed and decreases the upper loop bandwidth to increase a loop stability for the power control loop. Accordingly, the present invention not only improves the loop stability, but also the speed of the loop.
A system for measuring output power from an antenna. A sensor receives a sample of wireless signals from the antenna and communicates data about the signal back to the transmitter in a manner such that the antenna pattern is undisturbed. An optical coupler, e.g., fiber optic, is used to send data from the sensor to the transmitter. Power for the sensor can be derived parasitically from the wireless signal or can be provided to the sensor optically.
Methods in radio communications devices having a transmitter with an integral control loop, and in other integral control systems, including generating a first error signal (210) based upon an amplifier output signal and a corrected reference signal, generating a second error (220) signal based on a closed loop integral control signal applied to a control input of the amplifier and based on an integral control reference signal, and generating the corrected reference signal (230) by correcting a reference signal based upon the first and second error signals.
A subscriber unit and method for wireless communication that dynamically adjusts RF amplifier operating bias for the subscriber unit's transmitter in response to a power control signal. The invention provides high-efficiency RF power amplification for applications where the available power source is limited. The invention uses a power control signal resident in wireless communication system architectures with a detector and voltage to current converter to arrive at a dynamic amplifier operating bias.
