249 results about "Low frequency response" patented technology

According to various embodiments, an audio system having high quality sound and a high frequency response is provided. The audio system comprises one or more speakers with mismatched components. Although the combination of mismatched components may result in a diminished frequency response, digital signal processing may compensate for the physical deficiencies of a driver of the speaker. In some embodiments, an audio system comprises a speaker and a signal processor. The speaker may comprise one or more mismatched speaker components which are operably coupled to each other such that the components, together, have a low frequency response. The signal processor may operably couple to the one or more mismatched speaker components. The signal processor may be configured to process an input signal and to drive the speaker using the processed signal such that the speaker has a higher frequency response than the low frequency response.

Telephone line service type identification is provided to a telephone technician in the field by the placement of one or more tuned circuit(s) across the telephone line. In one embodiment, an inexpensive tuned circuit such as a ceramic resonator forms a telecom service resonator ID device which is placed across a telephone line, either at the central office or at the customer premises. Injection of a test current at a predetermined frequency, and a suitable amplitude of the same indicates to the technician aspects of telecom service to that particular telephone line (e.g., the existence of POTS, ISDN, and/or xDSL) and or use of the telephone line by a home network such as HPNA. In another embodiment, a telecom service transponder ID device is formed to provide line service identification to an interrogating line technician. The telecom service transponder ID device is activated when the test signal including an appropriate frequency is present to cause excitation in the telecom service transponder ID device. The resonator and transponder devices preferably have very high impedances at all frequencies except at the desired resonant frequency, and thus avoids violation of telephone service standards. The resonator or transponder ID devices may be placed anywhere along the telephone line, but preferably at the customer premises, or in installed equipment utilizing the telephone line. More than one resonation frequency may be implemented with parallel tuned circuits to indicate additional features of service on the telephone line (e.g., the number of services, the existence of a data service, etc.). The frequencies of resonance of the tuned circuits are preferably chosen to exist between the spectrum utilized by the various operating services. The transponder implementation may generate a simple low frequency response signal, or a more sophisticated specific data pattern using amplitude and/or frequency modulation.

Embodiments of the invention disclose a device and a method for screen vocal control, and a terminal, and the device and the method are applied in the field of screen vocal technique. The device for screen vocal control comprises a digital signal processor, a coder-decoder, a frequency divider, an amplifier, a driver, a motor, and a middle frame. The digital signal processor is used to perform analog-digital conversion processing on audio signals, to obtain digital signals. The coder-decoder is connected with the output end of the digital signal processor, and decodes digital signals to obtain decoded signals. The frequency divider is connected with the output end of the coder-decoder, and obtains high-frequency signals and low-frequency signals in the decoded signals. The amplifier is used to perform amplification processing on the high-frequency signals. The driver is connected with the output end of the amplifier, and drives a display screen to vibrate to sound. The motor is connected with the low-frequency signal output end of the frequency divider. The middle frame is connected with the motor, and the motor drives the middle frame to vibrate, so that the middle frame drives the display screen to vibrate and sound. Using the device and the method can ensure good low-frequency response effect of a screen vocal terminal.

A method and apparatus for driving lasers. An example laser driving system includes a laser current controller for providing a modulation signal and a bias signal. The modulation signal and bias signal is used by a plurality of high-speed current drivers that accept the modulation signal and the bias signal and produce a plurality of laser drive signals. The example system also has a disable input that disconnects power from a high-speed current driver when the high-speed current driver is not in use. The exemplary system develops the modulation and bias signals by feeding back a signal developed from detection of laser light from one of the lasers driven by the system. The laser may be a data laser or a control laser that is modulated by a signal having a lower frequency than the data lasers. If a control laser is used then the photodetector circuit used for feedback can have a lower frequency response because of the lower frequency of the control laser signal. The photodetector system may also employ a peak detector capacitor discharge circuit where a large capacitance is simulated by having the capacitor discharge through the base of a transistor have a current source in the emitter circuit.

A microphone system includes a diaphragm suspended by springs and including a sealing layer that seals passageways which, if left open, would degrade the microphone's frequency response by allowing air to pass from one side of the diaphragm to the other when the diaphragm is responding to an incident acoustic signal. In some embodiments, the sealing layer may include an equalization aperture to allow pressure to equalize on both sides of the diaphragm.

A method of intracranial ultrasound imaging applied in detecting a cranial blood vessel having blood filled with micro-bubbles formed by an injected contrast agent and generating blood vessel images includes: (1) emitting a plurality of ultrasound signals having bandwidths to the cranial blood vessel in sequence, (2) receiving an echoed signal from a micro-bubble, (3) performing a spectral analysis on the echoed signal and extracting a low-frequency response, the bandwidth of the low-frequency response similar to the bandwidth of the ultrasound signal, and (4) calculating a location and a depth of the micro-bubble in the cranium according to the low-frequency response and generating a corresponding blood vessel image.

The invention provides a sound-producing device of a display screen and a smart terminal. The sound-producing device of the display screen comprises a shell, the display screen and an exciter, whereinthe display screen is formed on one surface of the shell, and the exciter is arranged in the shell and located below the display screen; the exciter drives the display screen to produce sounds through vibration in the perpendicular direction of the display screen. In the sound-producing device, the display screen is pushed to vibrate in the front-and-back direction through the exciter to push airto produce the sounds through vibration; the larger display screen can move by smaller distance to push more air to produce the sounds which are equal to these of a telephone receiver in volume; low-frequency response is basically identical to that of the traditional telephone receiver, and has no obvious distorted peaks, the volume is basically identical to that of the traditional telephone receiver, and the price is lower than that in a scheme of piezoelectric ceramics.

A ultrasonic probe formed by arranging a plurality of ultrasonic vibrators each including a piezoelectric layer (2) and a pair of electrodes (7-1, 7-2) provided to sandwich this piezoelectric layer, the piezoelectric layer (2) consisting of a first piezoelectric layer (2-1) disposed on the ultrasonic wave outputting side across a common electrode (8) and a second piezoelectric layer (2-2) disposed on the opposite side, each ultrasonic vibrator having a uniform low-frequency response distribution in a minor-axis direction perpendicular to the arranging direction of the ultrasonic vibrators and having a high high-frequency response distribution at the center in the minor-axis direction, characterized in that the characteristics of the minor-axis-direction frequency and sound pressure of the first piezoelectric layer are complemented by those of the second piezoelectric layer to thereby make uniform frequency characteristics for a minor-axis-direction low frequency.

An externally ported speaker enclosure includes a primary enclosure having a port or opening. The primary enclosure may continuously vary from a first dimension to a dimension of the port or opening. Alternatively, a duct or tube may extend from, and external to, the primary enclosure. The duct or tube may transition from a first dimension to a dimension of the port or opening. The dimensions of the port, primary enclosure, and transition from primary enclosure to port are configured to reinforce the low frequency response of a speaker mounted to the enclosure. A cylindrical primary enclosure may transition gradually or continuously to a port. The cylindrical primary enclosure can include a closed first end and an open port end. A speaker can be mounted to the cylindrical face of the primary enclosure. Alternatively, the speaker may be mounted parallel to an axis of the cylinder.

A loudspeaker system has an extended bass or low frequency response. The loudspeaker system integrates a passive radiator with a transducer. The loudspeaker system also mechanically isolates the passive radiator and the transducer. A support mechanism mechanically grounds vibrations or other forces from the transducer and passive radiator that may interfere or affect the operation of the loudspeaker.

A sound reproduction system (10) is disclosed in which a sound barrier (14) defines a horn passageway having an upstream (22) and a downstream section (24). A driver (12) is mounted at the throat (16) of the upstream section (22) so that its rearward directed output communicates with the downstream section (24). Output from the upstream section and the rearward directed output of the driver are merged at a tap point located at the beginning of the downstream section. By altering the respective areas and lengths of the upstream and downstream sections a variety of different frequency dependent responses are obtained. In one example, low-frequency response systems of heretofore unobtainable compact size are realized.

A system and method employing a piezoelectric sensor for quasi-static force measurement substantially free of drift and with improved low-frequency response. The output signal from the sensor is sampled and integrated using digital techniques that include a drift compensation algorithm. The algorithm continually monitors the sensor output and estimates bias errors that will cause the output to drift.

The invention provides an acoustic absorbing material, comprising an MEL structure molecule sieve. A skeleton of the MEL structure molecule sieve comprises silicon dioxide. The acoustic absorbing material provided by the invention has uniform micropores. Under the effect of acoustic pressure, the micropores absorb air molecules, thereby increasing the volume of a virtual acoustic cavity. After the acoustic absorbing material is filled in a rear cavity of a loudspeaker, the low frequency response of the loudspeaker can be improved clearly, and the low frequency acoustic performance is improved. The invention also provides a preparation method for the acoustic absorbing material and the loudspeaker applying the acoustic absorbing material.

Improved performance of a noise separator circuit capable of separating common mode (CM) and differential mode (DM) components of electromagnetic interference (EMI) noise are provided by arrangement of terminating impedances such that the circuit is fully symmetric with respect of a pair of input ports. The noise separator circuit is further improved by perfecting features for canceling effects of parasitic inductances and capacitances, parasitic capacitance and inductance between circuit connections such as printed circuit board traces, minimizing leakage inductance effects of pairs of coupled inductors and mutual inductance effects between pairs of coupled inductors, providing sufficient magnetizing inductance for low frequency response, and preventing saturation of inductors using switched attenuators, providing a plurality of ground planes, choices of terminating resistors and circuit layout.

In an embodiment, a circuit includes a regulated power supply terminal, a processing circuit coupled to the regulated power supply terminal, and a low frequency responsive circuit having a first transistor adapted to be coupled to a power source and having first circuitry configured to control current flow from the power source through the first transistor to supply a low frequency current to the regulated power supply terminal. The circuit device further includes a high frequency responsive circuit having a second transistor coupled to the regulated power supply terminal and having second circuitry configured to control the second transistor to selectively modulate high frequency current components at the regulated power supply terminal to reduce voltage variations on the regulated power supply.

The invention discloses a device and method for measuring pulse wave velocity of human or mammal. The device comprises at least two sensors connecting with a signal processing element, wherein at least one of the first and second sensors is a diffused silicon pressure sensor. The signal processing element comprises amplifying circuits, a filter circuit, an analog to digital conversion circuit, and a main control circuit in sequential connection. The sensors are connected to the corresponding amplifying circuits respectively. The signal processing element also comprises signal separation circuit for separating transducer spikes. The method comprises obtaining maximum pulse signals, simultaneous recording two pulse wave signals with certain distance Delta s, abstracting characteristic reference point, calculating time interval difference Delta t of the signals, and calculating the pulse wave velocity. The device has the advantages of high safety, convenient operation, and good low-frequency response. The method has the advantages of reduced calculation amount, determined reference point, and high accuracy.

A driver circuit for a piezoelectric speaker is described, wherein charge is transferred from a charge reservoir to the speaker. In a first embodiment a delta sigma circuit uses a pulse width modulated digital audio signal to control a push-pull circuit to drive the piezoelectric speaker. High frequency harmonics are introduced to the delta sigma drive signals to enhance the low frequency response of the speaker. A charge recovery mechanism recovers charge from the speaker to reduce the frequency of replenishing the charge reservoir and to provide additional drive current for the speaker. In a second embodiment the pulse width modulated signal is used to drive a voltage quadrupling circuit that drives the piezoelectric speaker, wherein the reservoir capacitor is integrated with the capacitors of quadrupling circuit, which provides charge recovery.

A replica biased voltage regulator circuit (100) is disclosed that provides high frequency response via local positive feedback and low frequency response via a negative feedback loop. A voltage regulator circuit (100) can include current conveyor (106) that essentially forces an output voltage (Vload) to follow a replica voltage (Vrep). An operational amplifier (102) can provide negative feedback by controlling current supplied to the current conveyor (104) based on a comparison between a reference voltage (Vref) and the replica voltage (Vrep).

A sound chamber design of cell phones. The shell of the cell phone has a front sound hole, and a circuit board is in the internal space of the shell and divides the internal space into the first and the second sound chambers. A sounding device is in the first sound chamber and electrically connects the circuit board. The circuit plate has at least a sound through hole to link the first and the second sound chambers, to increase the volume of the resonance chamber of this sounding device and improve its low frequency response effect. In addition, the shell also has an attuning hole to link the first and the second sound chambers to the outside. The flattening of the resonance frequency curve of the whole cell phone improves the sound quality.

The invention relates to a planar loudspeaker composite vibrating diaphragm and an earphone loudspeaker with the same. A first sub-coil formed by wiring first conductors regularly is arranged on a first surface of the vibrating diaphragm, a second sub-coil formed by wiring second conductors regularly is arranged on a second surface of the vibrating diaphragm, the first sub-coil and the second sub-coil are connected serially, at least parts of projections of the first sub-coil and the second sub-coil on the plane of the vibrating diaphragm are overlapped, and directions of current of the overlapped parts of the first sub-coil and the second sub-coil are the same. The headset loudspeaker comprises the vibrating diaphragm and permanent magnets oppositely arranged at the positions of the coils on the vibrating diaphragm. The planar loudspeaker composite vibrating diaphragm has the advantages that the planar loudspeaker composite vibrating diaphragm of the composite structure is formed by serially connecting a plurality of coils, one coil is made of gold or platinum with good malleability, the other coil is made of other conventional metal materials, quality of the whole coils is controlled by controlling lengths and areas of the two coils, sound characteristics of the loudspeaker are controlled, and low-frequency response, high-frequency response and transient are more balanced.