A gain control apparatus for an amplifier is disclosed. The gain control apparatus configured to provide an amplifier gain control signal for setting the gain applied by the amplifier to an amplifier signal comprising an amplifier input signal amplified by the amplifier to generate an amplifier output signal. The apparatus includes a plurality of gain determination elements comprising and a gain controller configured to generate the amplifier gain control signal based on at least the first and second gain control signals.

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 radio frequency receiver is provided. The receiver can be employed in a low power (or ultra-low power) receiver architecture to generate a baseband signal or an intermediate frequency signal. In addition, the receiver includes capabilities of gain control to provide different gain settings as well as providing better/improved impedance matching control.

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.

Methods and systems are provided for gain control in circuits. Gain applied in a circuit may be set to a baseline set gain. A first baseline parameter, associated with a first feature of a particular pattern of a signal at said baseline set gain, and a second baseline parameter, associated with a second feature of said particular pattern of the signal at said baseline set gain, may be determined. The gain is then set a current set gain, and a gain compression ratio may be determined based on one or more of said first baseline parameter, said second baseline parameter, a first current parameter associated with said first feature of at said current set gain, and a second current parameter associated with said second feature at said current set gain. Said current set gain may then be adjusted until said gain compression ratio reaches a predefined limit.

The disclosure provides an amplifier. The amplifier includes a first transistor that receives a first input. A second transistor receives a second input. A plurality of impedance networks is coupled between the first transistor and the second transistor. At least one impedance network of the plurality of impedance networks includes a first impedance path and a second impedance path. The first impedance path is activated during single ended operation, and the second impedance path is activated during differential operation.

An RFID transponder having an analog front end receiver having an attenuator coupled to receive an RF-signal from an antenna and to attenuate the RF-signal, an amplifier having a fixed amplifier gain and being coupled to receive and to amplify the attenuated RF-signal and a control unit coupled to control a gain of the attenuator, wherein the control unit is configured to control the attenuator gain in response to a level of the amplified RF-signal, the control unit is configured to have a plurality of predetermined states causing the attenuator to increase (step-up) or to decrease (step-down), its gain by a predefined step size, wherein the step size of a step-up is equal to or smaller than the step size of a step-down and wherein the control unit is further configured to switch, upon reaching or exceeding a predefined threshold value, from a first to a second state having a smaller step size and causing the attenuator to change the gain such that the slope of the RF signal inverts and to switch, upon reaching the predefined threshold again, to a third state causing the attenuator to change a prefix of the gain.

A transmitter circuit comprises: an input, an encoder circuit, and a transmitter. During operation, the transmitter circuit receives an input signal. The encoder circuit encodes the received input signal into an encoded signal. The encoder circuit produces the encoded signal: i) to indicate changing states of the input signal, and ii) to include a supplemental transient signal with respect to the received input signal. The transmitter transmits the encoded signal from an output of the first circuit over a link to a second circuit such as a receiver circuit. A receiver decodes the encoded signal to reproduce a rendition of the input signal to control remote power supply circuitry. Presence of the supplemental transient signal in the encoded signal indicates to the receiver circuit that the first circuit actively transmits the output signal even though there may not be any change to a current state of the input signal.

A method for improving acoustics of amplitude modulation (AM) audio signal, comprising: amplifying and mixing, with an amplitude modulation (AM) front-end module, an analog AM signal and an automatic gain control (AGC) signal from an AGC module; converting and sampling, with an analog-digital converter and down-sampling module, the amplified and mixed signal to generate a digital AM signal; digitally mixing, with a digital mixer module, the digital AM signal to generate a first digital AM envelope signal; compensating, with an AM compensator module, the first digital AM envelope signal by an AM compensating AGC signal from the AM compensator module to generate a second digital AM envelope signal; demodulating, with a demodulation module, the second digital AM envelope signal; and outputting, with an output module, a demodulated AM audio signal.

A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.