In some implementations, a radiofrequency down converter comprises an input port to receive a radiofrequency input signal, and the down converter includes a first bandpass filter configured to filter the input signal. The down converter includes a mixer stage coupled to the bandpass filter, the mixer stage being configured to generate a mixer output signal by processing the filtered input signal using a gain adjustment device, one or more amplifiers, and a mixer. The down converter includes a signal adjustment stage coupled to receive the mixer output signal, the signal adjustment stage comprising: a temperature compensation device configured to compensate for changes in signal gain due to changes in temperature; a second bandpass filter; a gain adjustment device; one or more amplifiers; and a low pass filter. The down converter comprises an output port coupled to output an adjusted mixer output signal from the signal adjustment stage.

An equalizer, in at least some embodiments, comprises an amplifier configured to produce an amplified voltage signal that is a function of an ambient temperature affecting the equalizer. The equalizer also includes a linear equalizer stage coupled to the amplifier and comprising a transistor having a resistance controlled by the amplified voltage signal. The linear equalizer stage is configured to produce a voltage output signal having a gain that is dependent on the transistor resistance and on a frequency of the amplified voltage signal.

A passive bias temperature compensation module for silicon photomultiplier, avalanche photodiodes and similar photodetectors that possess a moderately linear temperature coefficient of gain and that may be compensated by varying an applied bias voltage. The module includes an electrical circuit and a method for determining component values to provide a constant voltage source to stabilize the gain of one or more photodetector devices. A temperature sensor in the module is held in close thermal contact with the photodetector and a filter capacitor is electrically close to the photodetector. The module is based on the concept of temperature sensitive voltage division which is applicable to situations in which large numbers of photodetectors must be gain-compensated for temperature variations over a wide range while maintaining excellent gain matching. The passive bias temperature compensation method enables multiple photodetectors to share a single constant voltage supply without loss of matching performance.

A temperature compensation circuit comprises a temperature coefficient circuit that generates a temperature coefficient that is temperature dependent and a compensation circuit that generates a compensation signal based on an indication of temperature of an amplifier and the temperature coefficient, and based on the compensation signal, a gain of the amplifier is adjusted to improve amplifier linearity during data bursts.

According to an embodiment, an electronic device may include: a first speaker configured to output a first audio signal corresponding to a first frequency band, a second speaker configured to output a second audio signal corresponding to a second frequency band at least partly different from the first frequency band, at least one amplifier configured to provide a first output signal for controlling output of the first speaker and a second output signal for controlling output of the second speaker, and at least one processor, comprising processing circuitry, operatively connected to the at least one amplifier. At least one processor, individually and/or collectively, may be configured to determine the first output signal, at least partly based on a first output control method; output the first audio signal, at least partly based on the first output signal, using the first speaker connected to the at least one amplifier; determine the second output signal, at least partly based on a second output control method; and output the second audio signal, at least partly based on the second output signal, using the second speaker connected to the at least one amplifier.

A radio-frequency amplifier can have an input stage that includes an amplifying transistor having an input node and an output node, such that a signal at the input node has a first power level and an amplified signal at the output node has a second power level. The radio-frequency amplifier can further include a bias circuit configured to provide a bias signal to the amplifying transistor, and a feedback circuit that couples the output node of the amplifying transistor to the input node of the amplifying transistor. The feedback circuit can include a resistance and a capacitance arranged in series. The radio-frequency amplifier can further include a gain compensation circuit implemented relative to the input stage such that the second power level is compensated for a variation in temperature associated with the radio-frequency amplifier.

Equalizing an input signal according to a receiver equalizer peaking circuit having a capacitor FET (CFET) providing a capacitive value and a resistor FET (RFET) providing a resistive value, generating a capacitor control voltage at a gate of the CFET using a capacitor controller DAC based on a first reference voltage, and a RFET control voltage at a gate of the RFET using a resistor controller DAC based on a second reference voltage, generating the first reference voltage using a replica input FET, the first reference voltage varying according to a threshold voltage (Vt) of an input FET, providing the first reference voltage to the capacitor controller DAC, generating the second reference voltage using a replica RFET, the second reference voltage varying with respect to the first reference voltage and a Vt of the replica of the RFET, and providing the second reference voltage to the resistor controller DAC.

To avoid damage from overheating, playback device operation can be modulated based on input from temperature sensors. An example method includes obtaining, via one or more temperature sensors carried by the playback device, temperature data. Based on the temperature data, a first temperature parameter is detected. In response to detecting the first temperature parameter, a gain of audio playback is decreased by a first amount. After decreasing the gain of audio playback by the first amount, a second temperature parameter is detected. In response to detecting the second temperature parameter, the gain of audio playback is decreased by a second amount different than the first amount.

Radio frequency (RF) power amplifier architectures and circuits providing compensated current and gain from turn-on to end of long signal burst intervals to counteract amplifier transistor thermal rise due to self-heating at turn-on. The RF receiver circuit may be implemented as one of a single chip device or as part of an integrated system of components for use in mobile communication systems.

To avoid damage from overheating, playback device operation can be modulated based on input from temperature sensors. An example method includes obtaining, via one or more temperature sensors carried by the playback device, temperature data. Based on the temperature data, a first temperature parameter is detected. In response to detecting the first temperature parameter, a gain of audio playback is decreased by a first amount. After decreasing the gain of audio playback by the first amount, a second temperature parameter is detected. In response to detecting the second temperature parameter, the gain of audio playback is decreased by a second amount different than the first amount.