Abstract:
A low-noise amplifier is provided that includes an input amplifier stage coupled to a plurality of independently switchable output amplifier stages. The input amplifier stage is operative to amplify an input communications signal, and it provides both an amplified communications signal and a feedforward signal. The amplified communications signal and the feedforward signal both include a distortion component. Each of the switchable output stages is operative to provide an output that combines the feedforward signal with the amplified communications signal in such a way that the distortion components of the signals at least partially cancel one another. In some embodiments, the switching of the output amplifier stages is performed by circuitry that also serves to improve reverse isolation of the separate output amplifier stages.
Abstract:
Disclosed herein are systems for and methods of using a mirrored wideband baseband current for automatic gain control of an RF receiver. In an embodiment, a system includes an RF receiver having an adjustable gain and being configured to direct convert a received wideband RF signal to a wideband baseband current signal. The system further includes a current replicator coupled to the receiver and configured to generate a mirrored current of the wideband baseband current signal. The system further includes a wideband signal-level detector configured to receive the mirrored current from the current replicator, and to measure and output a signal-level value of the mirrored current. The system further includes an automatic gain-control circuit configured to receive the signal-level value from the wideband signal-level detector, and to adjust the gain of the receiver based at least in part on the received signal-level value.
Abstract:
An apparatus with associated gain and input impedance includes gain devices, a switching unit and a resistor. A first differential pair of gain devices and associated bias circuitry is configured to operate in a full gain mode. A second differential pair of gain devices is configured to operate in a reduced gain mode. The switching unit is configured to disable the first differential pair of gain devices and enable the second differential pair of gain devices in the reduced gain mode and to disable the second differential pair of gain devices and enable the first differential pair of gain devices in the full gain mode. The resistor is configured to maintain constant input impedance of the apparatus when in the reduced gain mode.
Abstract:
A dual watch receiver is provided that, when operating in a single watch mode, receives a radio frequency (RF) signal, determines a signal quality metric associated with a received RF signal, and based on the determined signal quality metric, determines whether to route a same RF signal to only a first receiver path or to both of the first receiver path and a second receiver path, wherein the first receiver path and second receiver path process a received RF signal in parallel.
Abstract:
A current mode receiver front end for a radio device converts a received signal into a current mode signal and applies automatic gain control by both shunting current of the current mode signal and providing an adjustable series resistance that further adjust the current level of the current mode signal that is output by the receiver front end. The shunt and series circuits can be controlled by a digital control word whose value represent a decibel value of adjustment, and which is used to drive the shunt and series circuits to achieve both coarse and fine adjustment of the current mode signal.
Abstract:
An apparatus with associated gain and input impedance includes gain devices, a switching unit and a resistor. A first differential pair of gain devices and associated bias circuitry is configured to operate in a full gain mode. A second differential pair of gain devices is configured to operate in a reduced gain mode. The switching unit is configured to disable the first differential pair of gain devices and enable the second differential pair of gain devices in the reduced gain mode and to disable the second differential pair of gain devices and enable the first differential pair of gain devices in the full gain mode. The resistor is configured to maintain constant input impedance of the apparatus when in the reduced gain mode.
Abstract:
Disclosed herein are systems for and methods of using a mirrored wideband baseband current for automatic gain control of an RF receiver. In an embodiment, a system includes an RF receiver having an adjustable gain and being configured to direct convert a received wideband RF signal to a wideband baseband current signal. The system further includes a current replicator coupled to the receiver and configured to generate a mirrored current of the wideband baseband current signal. The system further includes a wideband signal-level detector configured to receive the mirrored current from the current replicator, and to measure and output a signal-level value of the mirrored current. The system further includes an automatic gain-control circuit configured to receive the signal-level value from the wideband signal-level detector, and to adjust the gain of the receiver based at least in part on the received signal-level value.