The present disclosure relates to methods and systems for LNAs with high linearity and low noise for wideband receivers that receive high dynamic range signals. A multi-stage multipath LNA is disclosed in which outputs from various stages are amplified with variable gains and combined in parallel. A smart gain control unit evaluates the noise and non-linearity characteristics associated with each gain stage to configure the variable gains for the various stages to generate an overall LNA gain that minimizes the overall noise and/or non-linearity characteristics of the LNA while ensuring that the overall gain for the LNA satisfies the desired gain. The variable gains may be configured to change smoothly over the dynamic range of the input signal. Noise is minimized by reducing additional gain stages and by the smooth change in gain when switching between stages. High linearity performance is maintained by minimizing the number of gain stages combined.

Techniques for providing low-cost and effective jammer rejection for an amplifier is disclosed. The amplifier includes an input node and an output node, a first transistor and a second transistor, a load circuitry, an inductor, and a capacitor. A first terminal of the first transistor is coupled to a ground. A second terminal of the first transistor is coupled to a first terminal of the second transistor. A second terminal of the second transistor is coupled to the output node. The load circuitry is coupled between a power supply and the second terminal of the second transistor. A first terminal of the inductor is coupled to the ground through a first switch. A first terminal of the capacitor is coupled to the first terminal of the second transistor and a second terminal of the capacitor is coupled to a second terminal of the inductor.

Disclosed herein is a DC offset cancellation circuit. The DC offset cancellation circuit includes a DC feedback unit configured to vary a DC feedback (DCFB) bandwidth to add at least one mid-bandwidth to the DCFB bandwidth and to provide a delay time in each case in order to reduce the DC droop error that occurs in switching from the high bandwidth (BW) to the mid-BW or from the mid-BW mode to the low BW mode, such that stable settling is ensured.

A wideband RF tuner with blocker signal detector for detection of blocking signals and for fast recovery from noise limited region.

A method and electronic circuit for changing the gain of a radio frequency signal. The apparatus is an electronic circuit comprising one or more variable gain electronic elements, and one or more adjustable phase shifting elements. The method comprises the steps of receiving a radio frequency signal, varying the gain of the variable gain electronic element while the variable gain electronic element changes the amplitude of the radio frequency signal, and adjusting an adjustable phase shifting element to generate a reverse phase shift in the radio frequency signal in response to the associated phase shift from the step of varying the gain.

A method is provided for operating a radio frequency (RF) receiver including a transimpedance amplifier, a capacitor selectively connected in parallel with the transimpedance amplifier, a channel selection filter unit connected to an output terminal of the transimpedance amplifier, and a variable gain amplification unit selectively connected in parallel with the channel selection filter unit. The method includes measuring signal-to-noise ratio from an output of the RF receiver, and comparing the measured signal-to-noise ratio with a reference signal-to-noise ratio. When the measured signal-to-noise ratio is greater than the reference signal-to-noise ratio, the capacitor is electrically disconnected from being connected in parallel with the transimpedance amplifier and a variation in the measured signal-to-noise ratio is measured. When the measured variation is in tolerance, the channel selection filter is bypassed to select the variable gain amplification unit.

Disclosed herein are envelope detectors with high input impedance, and related methods and systems. In some embodiments, an envelope detector with high input impedance may include: a swinging stage including first, second, and third transistors, wherein the third transistor and an active transistor are arranged as a differential pair, the first transistor is the active transistor when an input to the envelope detector is positive, and the second transistor is the active transistor when the input to the envelope detector is negative; and a feedback circuit, coupled to the swinging stage, to provide an output signal representative of a rectification of the input.

A method for dynamic sizing of a blocker margin by a receiver automatic gain control (AGC) is described. The method includes measuring a wanted signal level and a blocker signal level. The method also includes adjusting a linear target for the wanted signal level at the output of an analog-to-digital converter (ADC) of the receiver based on the blocker signal level. The linear target is adjusted to optimize a wanted signal signal-to-noise ratio (SNR) and the blocker margin. The method further includes adjusting a receiver front-end gain based on the adjusted linear target.

A wireless receiver, which receives a radio wave (RF) signal from a wireless microphone, demodulates an audio signal, and displays an RF reception state proportional to strength of a received signal on an indicator, includes a first frequency conversion (FC) unit generating a first IF signal based on the received RF signal; a second FC unit generating a second IF signal based on the first IF signal; a first received RF strength measuring unit detecting a first level signal from the first IF signal generated by the first FC unit; a second received RF strength measuring unit detecting a second level signal from the second IF signal generated by the second FC unit; and a synthesizing unit synthesizing the first level signal detected by the first received RF strength measuring unit and the second level signal detected by the second received RF strength measuring unit, and outputs a synthesized level signal.

A method is provided for operating a radio frequency (RF) receiver including a transimpedance amplifier, a capacitor selectively connected in parallel with the transimpedance amplifier, a channel selection filter unit connected to an output terminal of the transimpedance amplifier, and a variable gain amplification unit selectively connected in parallel with the channel selection filter unit. The method includes measuring signal-to-noise ratio from an output of the RF receiver, and comparing the measured signal-to-noise ratio with a reference signal-to-noise ratio. When the measured signal-to-noise ratio is greater than the reference signal-to-noise ratio, the capacitor is electrically disconnected from being connected in parallel with the transimpedance amplifier and a variation in the measured signal-to-noise ratio is measured. When the measured variation is in tolerance, the channel selection filter is bypassed to select the variable gain amplification unit.