Improved dither detection, measurement, and voltage bias adjustments for an electro-optical modulator are described. The electro-optical modulator generally includes RF electrodes and phase heaters interfaced with semi-conductor waveguides on the arms of Mach-Zehnder interferometers, where a processor is connected to output a bias tuning voltage to the electro-optical modulator for controlling optical modulation. A variable gain amplifier (VGA) can be configured with AC coupling connected to receive a signal from a transimpediance amplifier (TIA) that is configured to amply a photodetector signal from an optical tap that is used to measure an optical signal with a dither signal. The analog to digital converter (ADC) can be connected to receive output from the VGA. The processor can be connected to receive the signal from the ADC and to output the bias tuning voltage based on evaluation of the signal from the tap.

A power management circuit for fast average power tracking (APT) voltage switching is provided. The power management circuit includes a primary voltage circuit configured to generate an APT voltage based on an APT target voltage. However, the primary voltage circuit may be inherently slow in ramping up the APT voltage to the APT target voltage. As such, a secondary voltage circuit is provided in the power management circuit to help drive the APT voltage to a desired level by a defined temporal limit. Once the APT voltage reaches the desired level, the secondary voltage circuit will automatically shut off, while the primary voltage circuit continues operating at a selected duty cycle to maintain the APT voltage at the APT target voltage. By utilizing the secondary voltage circuit to quickly drive up the APT voltage, the power management circuit is capable of supporting dynamic power control under stringent switching delay budget.

According to one embodiment, a semiconductor device includes the following configuration. A detection circuit detects a state of a clock signal. An amplification circuit changes a gain based on the state of the clock signal detected by the detection circuit. An amplification circuit amplifies a first voltage with the gain and outputs a second voltage obtained as a result of amplification. A conversion circuit converts the second voltage output from the amplification circuit to first data. An isolation circuit includes a driver and a receiver electrically isolated from the driver. The driver transmits a signal corresponding to the first data to the receiver. The receiver outputs second data corresponding to the signal transmitted from the driver. The output circuit outputs the second data output from the isolation circuit.

According to one embodiment, a semiconductor device includes the following configuration. A detection circuit detects a state of a clock signal. An amplification circuit changes a gain based on the state of the clock signal detected by the detection circuit. An amplification circuit amplifies a first voltage with the gain and outputs a second voltage obtained as a result of amplification. A conversion circuit converts the second voltage output from the amplification circuit to first data. An isolation circuit includes a driver and a receiver electrically isolated from the driver. The driver transmits a signal corresponding to the first data to the receiver. The receiver outputs second data corresponding to the signal transmitted from the driver. The output circuit outputs the second data output from the isolation circuit.

Frequency domain compensation is provided for spectral impairment resulting from the audio path characteristics for a given audio device in a given listening space. Selected segments of an audio stream are recorded at a listener position to measure degradation in the audio path and to update compensation filter characteristics of the audio device. Recorded transmitted and received audio sequences are aligned based and compared in the frequency domain. The difference between the aligned transmitted and received sequences represents the frequency domain degradation along the acoustic path due to the speaker, the physical attributes of the room, and noise. A dynamically updated noise model is determined for adjusting compensation filter characteristics of the audio device, which can be updated during use of the audio device. A compensation curve is derived which can adapt the equalization of the audio device passively during normal usage.

An amplifier with temperature compensation where the amplifier has transistors configured to amplify a received signal to create an amplified signal. The amplifier gain changes over temperature. A gain control circuit, connected to the amplifier, that adjusts the amplifier gain responsive to a gain control signal. A temperature compensation circuit includes numerous elements. A constant current source that generates a constant current which is used to create a constant voltage. A temperature dependent current source that generates a temperature dependent current which is used to create a temperature dependent voltage, such that the temperature dependent current source has an inverse temperature dependance as compared to the amplifier. An operational amplifier compares the constant voltage to the temperature dependent voltage and generates an offset signal which varies over temperature. A gated buffer is configured to receive the offset signal and responsive thereto, selectively modify the gain control signal.

An amplifier with temperature compensation where the amplifier has transistors configured to amplify a received signal to create an amplified signal. The amplifier gain changes over temperature. A gain control circuit, connected to the amplifier, that adjusts the amplifier gain responsive to a gain control signal. A temperature compensation circuit includes numerous elements. A constant current source that generates a constant current which is used to create a constant voltage. A temperature dependent current source that generates a temperature dependent current which is used to create a temperature dependent voltage, such that the temperature dependent current source has an inverse temperature dependance as compared to the amplifier. An operational amplifier compares the constant voltage to the temperature dependent voltage and generates an offset signal which varies over temperature. A gated buffer is configured to receive the offset signal and responsive thereto, selectively modify the gain control signal.

A light detection and ranging (LIDAR) system includes an automatic gain control (AGC) unit to reduce the dynamic range, reducing processing power and saving circuit area and cost. The system detects a return beam of a light signal transmitted to a target, having a first dynamic range in a time domain. An analog to digital converter (ADC) generates a digital signal based on the return beam. A processor can perform time domain processing on the digital signal, convert the digital signal from the time domain to a frequency domain, and perform frequency domain processing on the digital signal in the frequency domain. The AGC unit can measure a power of the return beam, and apply variable gain in the frequency domain to reduce a dynamic range of the return beam to a second dynamic range lower than the first dynamic range.

In one aspect, an example method includes (i) determining, by a playback device, a loudness level of first media content that the playback device is receiving from a first source; (ii) comparing, by the playback device, the determined loudness level of the first media content with a reference loudness level indicated by a loudness level profile for the first media content; (iii) determining, by the playback device, a target volume level for the playback device based on a difference between the determined loudness level of the first media content and the reference loudness level; and (iv) while the playback device presents second media content from a second source in place of the first media content, adjusting, by the playback device, a volume of the playback device toward the target volume level.

An antenna controller for an antenna is configured to request and receive status information comprising power amplifier data of at least two adjustable power amplifiers. The antenna controller is configured to determine at least one target setting for the at least two adjustable power amplifiers based on the received power amplifier data, and to send the at least one target setting for the at least two adjustable power amplifiers. Hereby it is made possible for an antenna controller to set an overall target for multiple adjustable power amplifiers of the antenna. This in turn makes it possible to make the settings for the adjustable power amplifiers such that the transmission signal becomes linearized by a shared digital pre-distorter when transmitting using the multiple adjustable power amplifiers of the antenna. A Radio Frequency Integrated Circuit controller for an antenna subarray is configured to control at least one adjustable power amplifier.