Example techniques may provide volume enhancements to a media playback system. An example implementation involves a first playback device in a first playback configuration playing audio at a first volume level and storing the first volume level in association with the first playback configuration. The first playback device receives instructions to change to a second playback configuration. Based on receiving the instructions, the first playback device joins a synchrony group with a second zone and adjusts the first playback device to play audio at a second volume level which is based on a volume level of a second playback device in the second zone. While in the second playback configuration, the first playback device receives instructions to change to the first playback configuration and, based on the instructions, leaves the synchrony group and adjusts the first playback device to play audio content at the stored first volume level.

A number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

Example techniques may provide volume enhancements to a media playback system. An example implementation involves a first playback device in a first playback configuration playing audio at a first volume level and storing the first volume level in association with the first playback configuration. The first playback device receives instructions to change to a second playback configuration. Based on receiving the instructions, the first playback device joins a synchrony group with a second zone and adjusts the first playback device to play audio at a second volume level which is based on a volume level of a second playback device in the second zone. While in the second playback configuration, the first playback device receives instructions to change to the first playback configuration and, based on the instructions, leaves the synchrony group and adjusts the first playback device to play audio content at the stored first volume level.

Techniques for setting a gain of an amplifier circuit in which the external resistor of the amplifier circuit is used to determine an internal gain setting to select. A voltage across the external resistor can be compared to an on-chip reference, and then used to program the desired gain. The techniques can mitigate or eliminate the need for a high-accuracy external resistor and can allow substantial improvements in initial gain accuracy and gain drift for existing boards and/or systems with only a bill of material change.

An amplifier circuit 1001 with a variable temperature coefficient of a gain is an amplifier circuit with a variable temperature coefficient of a gain in which a variable resistor VR is connected between a first signal and a second signal having temperature coefficients of an amplification factor different from each other, a variable output of the variable resistor VR is connected to an input of a buffer amplifier Ub, and an output of the buffer amplifier Ub is used as an output Vo, wherein the first signal is an output of a first temperature coefficient circuit 100, and the second signal is an output of another amplifier circuit 501.

An apparatus for noise reduction in audio signal processing includes a power amplifier, a zero-crossing detector, and a threshold detector. The power amplifier has an input signal terminal for receiving an audio input signal and an output signal terminal. The audio input signal is a digital-to-analog converted version according to a version of a digital audio signal. The power amplifier has an analog gain which is controllable in response to an analog gain control signal. The zero-crossing detector determines a zero-crossing detection signal according to an internal signal provided between the input signal terminal and the output signal terminal. The threshold detector determines a gain setting according to the digital audio signal and the zero-crossing detection signal to generate the analog gain control signal indicating the gain setting, wherein the threshold detector controls the analog gain of the power amplifier according to the analog gain control signal.

A network transceiver device is provided, including at least two variable gain amplifiers (VGAs), and at least two sets of analog digital converters (ADCs), each set including ADCs coupled to an output of one of the VGAs, the sets being arranged in VGA-specific channels. The device includes a plurality of feed-forward equalizers (FFEs), each FFE being coupled to receive an output of one of the ADCs in one of the VGA-specific channels. Each FFE is configured to adaptively equalize the output received from the ADCs utilizing a first equalization coefficient subset with coefficient values that are common to all FFEs, and a second equalization coefficient subset that is channel specific and that has a first set of coefficient values for a first VGA-specific channel and a second set of coefficient values for a second VGA-specific channel, the sets of coefficient values being computed independently.

An asymmetric signal path approach is used to extract differential signals out of the photodetector (e.g., a photodiode) for amplification by a differential transimpedance amplifier (TIA). This asymmetric-path differential TIA configuration has less low-frequency Inter Symbol Interference (ISI) (also known as Baseline Wander), less high-frequency noise amplification, and higher bandwidth capabilities. There is no power penalty with this design in comparison to a single-ended TIA, can extend the range of the link for a given system power consumption, and can decrease transmitter power for a given range.

Disclosed is a low noise amplifier system. Included is a main amplifier having a main input coupled to a RF input and a main output connected to an RF output and an impedance amplifier having an impedance input coupled to the RF input and an impedance output coupled to the RF output, wherein the impedance amplifier is configured to provide input impedance matching to the main amplifier. The impedance amplifier also provides a first noise path that passes through the impedance amplifier such that the noise generated by the impedance amplifier is substantially out of phase with the noise that passes through a second noise path that passes through the main amplifier.

An apparatus and method for processing signals in the analog domain. A signal is derived from analog circuit properties that is shift and scale invariant. Although the circuit properties are not quantized as in traditional digital signal processing, the signal is immune from effects of the properties, such as common mode noise, absolute voltage or current level, finite settling time, etc., as a digital signal would be. The shift and scale invariance allows for mathematical operations of addition, subtraction, multiplication and division of signals. By combining these operations, various circuits may be constructed, including a voltage controlled amplifier, a time gain amplifier, and an analog-to-digital converter. The circuits are constructed using almost no non-linear, active devices, and will thus use less power for a given speed than comparable digital devices, and will often be faster as there are no delay elements and no need to wait for the circuit properties to settle.