83 results about "Crossover distortion" patented technology

An integrated circuit provides a complete electronic ballast control with power factor correction for fluorescent lamps. The integrated circuit contains a simplified power factor correction (PFC) circuit to reduce component count and supply voltage requirements to reduce manufacturing costs while providing a robust control. The PFC circuit has a variable gain for fast response at high gain and optimized power factor control at low gain. An increased on time for the PFC switch when the input line voltage approaches zero dynamically reduces crossover distortion, thereby reducing total harmonic distortion. The integrated circuit incorporates a number of fault protections.

A system and method for power conversion synchronizes multiple phases at a desired phase angle difference. The power conversion involves variable frequency switching, fixed on-time and provides power factor correction. A relative measure of a phase angle difference between two phases permits each phase to be controlled to obtain the desired phase angle difference. The power conversion involves transition mode switching to help reduce switching losses. A phase angle difference detector may be provided for each phase. The various phases may have different inherent frequencies that vary with switching frequency, and are synchronized to an average frequency. Current measures can be taken with a single component, such as a resistor. A maximum frequency control limits period width to avoid high frequency switching. An added switch on time improves input voltage crossover distortion. One or more phases can be deactivated in light load conditions.

A testing method or apparatus utilizes filter banks to measure time varying or dynamic harmonic distortion or intermodulation distortion. With a stairstep signal and filter banks, Nth order harmonic and or intermodulation distortion is measured via the filter banks at different offsets provided by an arbitrary low frequency signal. An amplifier with crossover distortion will show increased harmonic and or intermodulation distortion near the zero crossing while providing less distortion in other portions of the transfer curve of the amplifier.

The invention discloses a broadband piezoelectric vibration energy collection system. The system comprises a frequency collection circuit, a voltage stabilizing push-pull circuit and an operational amplifier circuit. The frequency collection circuit collects the frequency of the electric power signal collected by a broadband piezoelectric vibration energy collection system, the voltage stabilizingpush-pull circuit uses a frequency modulation circuit composed of a triode Q1, a capacitor C2 and a capacitor C4 to stabilize the signal frequency, simultaneously uses an operational amplifier AR1 and an operational amplifier AR2 to form a feedback voltage stabilizing circuit for voltage stabilization, and finally uses a triode Q4 to a triode Q7 to form the push-pull circuit to prevent the signalfrom crossover distortion; and the operational amplifier circuit uses an operational amplifier AR3 to perform in-phase amplification of the signal and simultaneously filters the signal by employing aRC filtering circuit composed of a resistor R20, a resistor R21, a capacitor C8 and a capacitor C9 to send the signal to the remote control terminal of the broadband piezoelectric vibration energy collection system through an emitter E1 so as to collect the electric energy power signal frequency collected by the broadband piezoelectric vibration energy collection system in real time, perform automatic calibration of the signal and prevent the data signal from distortion.

The invention discloses an industrial equipment operation monitoring signal adjusting circuit. The circuit comprises a frequency acquisition circuit, a separation switch circuit and a push-pull outputcircuit. The frequency acquisition circuit acquires analog signal frequency received by the industrial equipment operation monitoring control terminal. According to the separation switch circuit, a triode Q5, a variable resistor RW1, a capacitor C4 and a capacitor C5 form a synchronous separation circuit to divide a signal into two paths of signals with the same frequency and different amplitudes; a capacitor C2, a capacitor C3, an inductor L4 and a triode Q1 are used in one parth to form a frequency modulation circuit to adjust the signal frequency; in the second path, a diode D1, a diode D2and a capacitor C6 form a noise reduction circuit to reduce the signal-to-noise ratio; and finally, the push-pull output circuit uses a triode Q7 and a triode Q8 to form a push-pull circuit to prevent signal crossover distortion, and the signal is output after being stabilized by a voltage stabilizing tube D3, i.e., a compensation signal of an analog signal received by the industrial equipment operation monitoring control terminal, so that high-frequency component attenuation is overcome.

A testing method or apparatus utilizes a filter or modifier to measure time varying or dynamic harmonic, intermodulation, cross modulation, and or N-Beat or triple distortion from a device. With a stairstep or arbitrary signal and another signal, Nth order harmonic, cross modulation, triple beat, N-Beat, and or intermodulation distortion is measured via the filter or modifier at different offsets or time provided by an arbitrary low frequency signal. For example, an amplifier with crossover distortion will show increased (e.g., time varying) harmonic, cross modulation, triple beat, and or intermodulation distortion near the zero crossing while providing less distortion in other portions of the transfer curve of the amplifier. One or more distortion signals from the device (e.g., audio device) may be measured for a phase and or frequency modulation effect.

A testing method or apparatus utilizes filter banks to measure time varying or dynamic harmonic distortion or intermodulation distortion from a device. With a stairstep or arbitrary signal and filter banks, Nth order harmonic and or intermodulation distortion is measured via the filter banks at different offsets provided by an arbitrary low frequency signal. An amplifier with crossover distortion will show increased harmonic and or intermodulation distortion near the zero crossing while providing less distortion in other portions of the transfer curve of the amplifier. One or more distortion signals from the device (e.g., audio device) may be measured for a phase and or frequency modulation effect.

A push-pull amplifier having low output impedance and low crossover distortion is provided. A least one of a current through a sourcing current path of an output stage and a current through a sinking current path of the output stage is determinative of a quiescent current control signal produced for controlling a quiescent current of the amplifier. The quiescent current is controlled by symmetrically controlling a bias voltage applied to a sourcing active output device and a bias voltage applied to a sinking active output device in response to the quiescent current control signal. An output stage sourcing control signal for controlling the sourcing active output device is referenced directly to a shared terminal of the sourcing active output device, and an output stage sinking control signal for controlling the sinking active output device is referenced directly to a shared terminal of the sinking active output device.

A testing method or apparatus utilizes a filter or modifier to measure time varying or dynamic harmonic, intermodulation, cross modulation, and or N-Beat or triple distortion from a device. With a stairstep or arbitrary signal and another signal, Nth order harmonic, cross modulation, triple beat, N-Beat, and or intermodulation distortion is measured via the filter or modifier at different offsets or time provided by an arbitrary low frequency signal. For example, an amplifier with crossover distortion will show increased (e.g., time varying) harmonic, cross modulation, triple beat, and or intermodulation distortion near the zero crossing while providing less distortion in other portions of the transfer curve of the amplifier. One or more distortion signals from the device (e.g., audio device) may be measured for a phase and or frequency modulation effect.

The invention discloses a power amplifier circuit powered by a single power supply based on an MOS transistor. The circuit comprises a power amplification circuit and an intermediate amplifier. The power amplification circuit is electrically connected with the intermediate amplifier, the power amplification circuit comprises a positive half-cycle power amplification circuit, a negative half-cyclepower amplification circuit and an impedance matching output transformer, and a class B single-power-supply transformer coupling push-pull power analog linear amplification circuit is formed by connecting power MOS single tubes or multiple tubes with the same characteristics in parallel; the intermediate amplifier comprises an output feedback detection circuit, a proportional integral differentiating circuit, a positive and negative half-cycle balance and crossover distortion correction circuit and a protected positive and negative half-cycle voltage follower circuit. The power amplifier circuit is directly installed in a power amplifier, a voltage type MOS tube is adopted as a power tube, a front end circuit is simple and reliable, universality is large, the size is small, reliability ishigh, power matching is simple, and the power amplifier circuit is particularly suitable for a broadcast power amplifier machine requiring alternating current and direct current, and full-power outputthe same as that of alternating current power supply is kept during direct current power supply.

The invention belongs to the technical field of electronics and audio amplification, and relates to a hearing-aid made of a TDA2822 (Tunnel Diode Amplifier). The hearing-aid comprises a direct current (DC) power supply, a power supply filter circuit, a constant current source and pickup circuit, an emitter follower, an audio signal regulating circuit and an integrated power amplification circuit. The hearing-aid is characterized in that the constant current source and pickup circuit is used as a power supply of a capacitor microphone (MIC), the emitter follower is used as a high-resistance amplification circuit, and the type of the integrated power amplification circuit (IC1) in a BTL (Bridge-Tied-load) mode application circuit is TDA2822M. The hearing-aid provided by the invention is formed by combining discrete components and the integrated power amplification circuit. The hearing-aid has the characteristics of simple circuit structure, fewer peripheral elements, little cross distortion, good tone quality, wide working voltage range, less static current and electricity consumption, output power capable of meeting the requirements on people with poor hearing, and the like, and is a hearing-aid attractive in price and quality, thereby solving or overcoming the problems of partial defects existing in some hearing-aids on the market, and the like.

The invention discloses an output amplifier comprising transistors and a field-effect transistor. A base of a first transistor serves as a signal output end, and a drain electrode and a source electrode of the field-effect transistor form a signal output end. The first transistor and a second transistor form a differential input electrode and a third transistor forms a high-gain intermediate amplifier to prevent signals from generating crossover distortion so as to influence output signal power. Negative feedback is utilized to increase gain, output power is large and application is convenient.

The invention discloses a total harmonic distortion optimization analog multiplier, which mainly solves the problems of large crossover distortion and low power factor in the prior art. A first input signal MULTIN, a second input signal COMP and a first reference voltage VPEF1 are converted into four paths of current signals I1 to I4 to a multiplying circuit through three voltage/current conversion circuits respectively; a product circuit performs multiplying and dividing operation on the currents I1 to I4 and outputs a total current IO into the current/voltage conversion circuit; the current/voltage conversion circuit performs I-V conversion on the total current IO output by the product circuit and outputs a voltage product (PRODUCT) into a high clamping circuit of output voltage; and a multiplying signal PRODUCT is highly clamped on a second reference voltage VREF2 through the high clamping circuit of the output voltage. The multiplier realizes multiplying function according to the logarithmic relationship between the voltage VBE between the base and the emitter of a triode and current IC of the collector and can reduce the total harmonic distortion produced by the crossover distortion so as to improve the power factor and be used for an active power factor corrector.