The invention relates to the technical field of earphone horn, more particular, relates to a horn of an integrated frequency division circuit, which includes a shell, a moving iron unit and a frequency division PCB connecting plate. The top surface of the frequency division PCB connecting plate is contacted with the bottom surface of the moving iron unit, and the side surface of the frequency division PCB connecting plate is connected with the inner edge of the bottom part of the shell; the frequency division PCB connecting plate is provided with an electronic frequency division circuit electrically connected with the moving iron unit. The horn of the integrated frequency division circuit integrates the electronic frequency division circuit, thus has the function of electronic frequency division, it reduces the production cost and the welding step, then enhances the production quality and the production efficiency.

The invention relates to the technical field of earphone horn, more particular, relates to a horn of an integrated frequency division circuit, which includes a shell, a moving iron unit and a frequency division PCB connecting plate. The top surface of the frequency division PCB connecting plate is contacted with the bottom surface of the moving iron unit, and the side surface of the frequency division PCB connecting plate is connected with the inner edge of the bottom part of the shell; the frequency division PCB connecting plate is provided with an electronic frequency division circuit electrically connected with the moving iron unit. The horn of the integrated frequency division circuit integrates the electronic frequency division circuit, thus has the function of electronic frequency division, it reduces the production cost and the welding step, then enhances the production quality and the production efficiency.

An apparatus includes a circuit and a shifter. The circuit may be configured to generate a control signal based on a reference voltage and a plurality of characteristics of an amplifier. The shifter may be configured to (i) receive an input signal carrying a pulse burst having a plurality of pulses, (ii) shift a plurality of phases of the pulses in the pulse burst in response to the control signal, and (iii) present the pulses as shifted in an output signal.

Disclosed are an apparatus and method of processing an audio signal to optimize audio for a room environment. One example method of operation may include recording the audio signal generated within a particular room environment and processing the audio signal to create an original frequency response based on the audio signal. The method may also include identifying a target sub-region of the frequency response which has a predetermined area percentage of a total area under a curve generated by the frequency response, determining whether the target sub-region is a narrow energy region, creating a filter to adjust the frequency response, and applying the filter to the audio signal.

A pulse modulator receives an analog voltage V.sub.IN, and generates a pulse signal that is modulated according to the analog voltage V.sub.IN. An output stage generates a switching signal at an output terminal according to the pulse signal. A semiconductor integrated circuit is switchable between (i) a normal mode in which a main signal V.sub.MAIN to be used in a normal operating mode is input as the analog voltage V.sub.IN to the pulse modulator, and (ii) a test mode in which at least one internal analog signal V.sub.AUX generated in the semiconductor integrated circuit is input as the analog voltage V.sub.IN to the pulse modulator.

Techniques to improve efficiencies of power amplifiers in wireless communication devices are described herein. In one embodiment, an envelope tracking supply modulator includes a pre-amplifier having an input coupled to an envelope signal and another input coupled to a threshold voltage signal, a de-multiplexer coupled to an output of the pre-amplifier, a pulse frequency modulator having an input coupled to an output of the de-multiplexer, and a pulse width modulator having an input coupled to the output of the de-multiplexer. The de-multiplexer is configured to allow the pulse frequency modulator to modulate a switching frequency to generate a switched signal according to a slew rate of the envelope signal or allow the pulse width modulator to provide the switched signal as a current source with a constant frequency, based on a comparison result between the envelope signal and the threshold voltage signal at the pre-amplifier.

Disclosed are an apparatus and method of processing an audio signal to optimize audio for a room environment. One example method of operation may include recording the audio signal generated within a particular room environment and processing the audio signal to create an original frequency response based on the audio signal. The method may also include identifying a target sub-region of the frequency response which has a predetermined area percentage of a total area under a curve generated by the frequency response, determining whether the target sub-region is a narrow energy region, creating a filter to adjust the frequency response, and applying the filter to the audio signal.

Disclosed are an apparatus and method of processing an audio signal to optimize audio for a room environment. One example method of operation may include recording the audio signal generated within a particular room environment and processing the audio signal to create an original frequency response based on the audio signal. The method may also include identifying a target sub-region of the frequency response which has a predetermined area percentage of a total area under a curve generated by the frequency response, determining whether the target sub-region is a narrow energy region, creating a filter to adjust the frequency response, and applying the filter to the audio signal.

Circuit topologies and control methods for a dc-to-rf converter circuit are described.

Techniques to improve efficiencies of power amplifiers in wireless communication devices are described herein. In one embodiment, an envelope tracking supply modulator includes a pre-amplifier having an input coupled to an envelope signal and another input coupled to a threshold voltage signal, a de-multiplexer coupled to an output of the pre-amplifier, a pulse frequency modulator having an input coupled to an output of the de-multiplexer, and a pulse width modulator having an input coupled to the output of the de-multiplexer. The de-multiplexer is configured to allow the pulse frequency modulator to modulate a switching frequency to generate a switched signal according to a slew rate of the envelope signal or allow the pulse width modulator to provide the switched signal as a current source with a constant frequency, based on a comparison result between the envelope signal and the threshold voltage signal at the pre-amplifier.