Examples disclosed herein relate to a dynamic supply modulation power amplifier architecture for millimeter wave applications. The architecture includes phase shifters coupled to a power input port, power amplifiers coupled to respective power output ports, variable gain amplifiers coupled to the phase shifters and to the power amplifiers and are configured to supply dynamically varying input power to the power amplifiers. The architecture includes a first look-up table coupled to the variable gain amplifiers to control the variable gain amplifiers. The architecture also includes a second look-up table coupled to the power amplifiers, where each of the power amplifiers is supply modulated by active drain voltage modulation controlled by the second look-up table and variable input power from the variable gain amplifiers. Other examples disclosed herein include a radar system for use in an autonomous driving vehicle and an analog beamforming antenna for millimeter wave applications.

Signal energy in auditory sub-bands of an input audio signal is determined. Sound pressure level, SPL, in those sub-bands is then determined, based on the signal energy and based on sound output sensitivity of the against-the-ear audio device. In one instance, at least first and second gain lookup tables are determined based on a hearing profile of a user of the against-the-ear audio device. Sub-band gains that are to be applied to the input audio signal are determined based on the determined SPL. When the input audio signal is for example telephony the sub-band gains are computed using the first gain lookup table, and when the input audio signal is for example media the sub-band gains are computed using the second gain lookup table. Other aspects are also described and claimed.

A D/A converter coverts a digital audio signal into an analog audio signal. An analog volume circuit receives an output of the D/A converter. A controller controls the analog volume circuit. The controller shortens transition time at each step in the analog volume circuit further as gain is lower.

A system may include a digital modulator configured to modulate an input signal received at an input of the digital modulator to generate a modulated input signal at an output of the digital modulator, a digital gain element having a digital gain and coupled to the digital modulator, an open-loop Class-D amplifier coupled to an output of the digital modulator and configured to amplify the modulated input signal, wherein the open-loop Class-D amplifier is powered from a variable power supply having a variable supply voltage which is variable in response to one or more characteristics of the input signal, and a control circuit configured to control the digital gain to approximately cancel changes in an analog gain of the open-loop Class-D amplifier due to variation in the variable supply voltage in response to the one or more characteristics of the input signal.

Examples disclosed herein relate to a dynamic supply modulation power amplifier architecture for millimeter wave applications. The architecture includes phase shifters coupled to a power input port, power amplifiers coupled to respective power output ports, variable gain amplifiers coupled to the phase shifters and to the power amplifiers and are configured to supply dynamically varying input power to the power amplifiers. The architecture includes a first look-up table coupled to the variable gain amplifiers to control the variable gain amplifiers. The architecture also includes a second look-up table coupled to the power amplifiers, where each of the power amplifiers is supply modulated by active drain voltage modulation controlled by the second look-up table and variable input power from the variable gain amplifiers. Other examples disclosed herein include a radar system for use in an autonomous driving vehicle and an analog beamforming antenna for millimeter wave applications.

A system may include a digital modulator configured to modulate an input signal received at an input of the digital modulator to generate a modulated input signal at an output of the digital modulator, a digital gain element having a digital gain and coupled to the digital modulator, an open-loop Class-D amplifier coupled to an output of the digital modulator and configured to amplify the modulated input signal, wherein the open-loop Class-D amplifier is powered from a variable power supply having a variable supply voltage which is variable in response to one or more characteristics of the input signal, and a control circuit configured to control the digital gain to approximately cancel changes in an analog gain of the open-loop Class-D amplifier due to variation in the variable supply voltage in response to the one or more characteristics of the input signal.

A compensation method for a characteristic difference of a photoelectric element is disclosed. The method includes (S1) providing a test substrate with a connector, a photoelectric element and a plurality of gain units, wherein the plurality of gain units are connected in parallel, and each gain unit includes a gain resistor and a disconnection port; (S2) connecting the connector to a test fixture which includes a test resistor and a test control unit, wherein when the test fixture is connected with the connector, the test resistor is electrically connected between the second pin and the third pin; (S3) providing input power to the connector so as to generate a test voltage on the photoelectric element; (S4) selecting the corresponding gain unit according to the test voltage and a classification data table; (S5) driving a production line to connect the first contact and the second contact of the selected gain unit.

An automatic gain control apparatus includes an amplitude detecting circuit, a distortion detecting circuit, a gain determining circuit and an amplifying circuit. The amplifying circuit applies a gain to an input signal to generate an output signal. The amplitude detecting circuit detects an average amplitude of the input signal. The distortion detecting circuit detects a distortion level of the output signal. The gain determining circuit determines the gain used by the amplifying circuit according to the average amplitude and the distortion level.

A D/A converter coverts a digital audio signal into an analog audio signal. An analog volume circuit receives an output of the D/A converter. A controller controls the analog volume circuit. The controller shortens transition time at each step in the analog volume circuit further as gain is lower.

A compensation method for a characteristic difference of a photoelectric element is disclosed. The method includes (S1) providing a test substrate with a connector, a photoelectric element and a plurality of gain units, wherein the plurality of gain units are connected in parallel; (S2) connecting the connector to a test fixture which includes a test resistor and a test control unit, wherein when the test fixture is connected with the connector, the test resistor is electrically connected between the second pin and the third pin; (S3) providing input power to the connector so as to generate a test voltage on the photoelectric element; (S4) selecting the corresponding gain unit according to the test voltage and a classification data table; (S5) driving a production line to connect the first contact and the second contact of the selected gain unit.