Abstract:
A micro speaker assembly including a micro speaker having a top plate, a bottom plate parallel to the top plate, a magnet assembly coupled to one of the top plate or the bottom plate, a compliant member positioned between the magnet assembly and the top plate or the bottom plate, the compliant member operable to be displaced in response to an acoustic input, and a voice coil coupled to the compliant member. The assembly further including an optical sensor coupled to the micro speaker, the optical sensor having a light emitter and a light detector, the light emitter and the light detector being fixedly coupled to the top plate or the bottom plate, and the optical sensor being operable to produce a displacement signal corresponding to a displacement of the compliant member and a temperature signal corresponding to a temperature of the magnet assembly.
Abstract:
A power converter has an output that is coupled in parallel with an energy reservoir circuit and a power supply node of an audio power amplifier. The converter can set an upper limit on its input supply current that is variable in accordance with a control input. A controller is to produce a signal, coupled to the control input of the power converter, that is responsive to a measure of input supply voltage of the power converter and either output voltage of the power converter or output power of the amplifier. Other embodiments are also described and claimed.
Abstract:
A method for audio signal processing, where an audio amplifier drives a load through a connector, using 1) an input audio signal, and 2) a signal from a return pin of the connector. Output headroom of the audio amplifier is automatically detected, while the amplifier is driving the load. A variable resistor circuit that is coupled to provide variable resistance between the return pin of the connector and a ground plane, is automatically adjusted, in response to the detected output headroom of the amplifier. Other embodiments are also described and claimed.
Abstract:
A programmed data processor receives input voltage measurements for a number of speaker drivers, wherein each of the voltage measurements may be a sensed or estimated sequence of time-domain samples of a respective speaker driver input voltage that is over a different time frame. The processor obtains a sensed shared current, being a measure of current in a single power supply rail that is feeding power to each of a number of audio amplifiers, while the audio amplifiers are driving the speaker drivers in accordance with a number of audio channel signals, respectively. The processor computes an estimate of electrical input impedance for each of the speaker drivers using the sensed shared current and the input voltage measurements. Other embodiments are also described and claimed.
Abstract:
An audio system bus has a bus data line and a bus clock line. Audio producers are coupled to the bus to form a time-division multiplexed multi drop bus interface arrangement having protocol slots 0,1, . . . N where N is an integer greater than two. A bus device is coupled to the bus that produces a) a frame marker on the bus data line in slot 0, and b) a data bit on the bus data line in slot 1. The audio producers are to produce their respective audio data bits in their assigned slots other than slots 0 and 1. Other embodiments are also described and claimed.
Abstract:
An audio amplifier has a first H bridge and a second H bridge, to drive a speaker as a load. The second H bridge drives the speaker through resistors for increased output impedance. Control logic operates the first H bridge as a class D amplifier for larger amplitudes of audio signal, and operates the second H bridge as a class D amplifier for smaller amplitudes of audio signal. Other aspects are also described and claimed.
Abstract:
An excitation signal is produced on a plate of an unknown capacitor and on a plate of a known capacitor. The excitation signal is amplified over time to produce a first output signal, with gain that is proportional to capacitance of the unknown capacitor. The excitation signal is also amplified over time to produce a second output signal, with gain that is proportional to capacitance of the known capacitor. Capacitance of the unknown capacitor is computed using a mathematical function of the first and second output signals and the capacitance of the known capacitor, while being insensitive to amplitude of the excitation signal. Other embodiments are also described and claimed.
Abstract:
A multi-channel audio system that can provide a variable sub-sample delay between two or more audio channels. In one embodiment, a variable timing clock generator generates multiple clock signals where each may have different phase, and the clock generator can vary the phase difference, in accordance with a sub-sample delay setting input. These clock signals are used by respective digital-to-analog converters (DACs) to convert the digital audio channels into analog form. In another embodiment, a variable delay block is added to an oversampling DAC, on a per channel basis. Other embodiments are also described and claimed.
Abstract:
A computer system having a loudspeaker mounted on a main logic board by a hermetic seal, is disclosed. More particularly, embodiments of the computer system include an acoustic cavity defined between the loudspeaker, the main logic board, and the hermetic seal. Embodiments of the computer system may include a compressible seal separated from the hermetic seal by the loudspeaker and/or the main logic board. The compressible seal may define an acoustic channel and the loudspeaker may emit sound in a high frequency range through the acoustic channel toward a system exit. Other embodiments are also described and claimed.
Abstract:
A multi-channel audio system that can provide a variable sub-sample delay between two or more audio channels. In one embodiment, a variable timing clock generator generates multiple clock signals where each may have different phase, and the clock generator can vary the phase difference, in accordance with a sub-sample delay setting input. These clock signals are used by respective digital-to-analog converters (DACs) to convert the digital audio channels into analog form. In another embodiment, a variable delay block is added to an oversampling DAC, on a per channel basis. Other embodiments are also described and claimed.