6 results about "Amplitude modulation" patented technology

The invention discloses a wide-dynamic high-accuracy and edge time adjustable impulse wave producing method which is characterized by including the following steps: (1) arranging an impulse generator; (2) building an impulse wave model according to waveforms of impulse signals generated by the impulse generator; (3) determining the amplitude modulation position according to the impulse wave model built in the step (2); (4) arranging an amplitude modulator; (5) setting a field programmable gate array (FPGA) waveform processing unit; (6) arranging a state machine and a direct digital frequency synthesizer (DDS) cooperating with the state machine in work; and (7) leading the state machine and the direct digital frequency synthesizer to cooperate in work and leading details of impulse waveforms after fine adjustment to be completely displayed. The wide-dynamic high-accuracy and edge time adjustable impulse wave producing method uses the method of amplitude for time, leads impulse edges and impulse width to be subjected to wide-dynamic and high-accuracy adjustment completely through the digital measures, simplifies complexity of a signal source analog channel circuit, saves cost and reduces production debugging operation difficulty.

The present invention provides a fingerprint direction feature obtaining method based on a striped pattern, and relates to the fingerprint automatic identification technology, etc. The method comprises three portions consisting of fingerprint image preprocessing, obtaining of three-dimensional single-base signals and obtaining of direction information. A fingerprint image is taken as a typical striped pattern, namely two-dimensional demodulated frequency modulation and amplitude modulation signals; two radian transition operators are employed to perform analysis solution of fingerprint signals to obtain three-dimensional single-base signals corresponding to the fingerprint signals; and according to the property of the single-base signals, the fingerprint direction information is obtained under polar coordinates. Compared to a traditional method, the fingerprint direction feature obtaining method based on the striped pattern eliminates the influence of noise and gray compensation values, has high anti-noise performance, and increases the credibility of a calculation result; and moreover, the operation of obtaining the fingerprint direction information in a frequency domain can directly eliminate the amplitude information in the fingerprint signals to obtain direction information representing the fingerprint uniqueness, avoid the problem that the modulation signals are not continuous in direction caused by the cosine function value restriction and reduce the unnecessary processing links so as to reduce the time cost of the identification system and effectively improve the identification efficiency of the system.

A device and method is provided for stimulation of neurons. The device includes a stimulation unit that can be implanted into a body of a patient and has stimulation elements that apply a stimulation signal to tissue of the patient to stimulate neurons in the brain and/or the spinal cord of the patient. Moreover, a measuring unit receive a measurement signal that reflects a neuronal activity of the stimulated neurons. Further, a control unit generate a modulation signal from the measurement signal, and modulates an amplitude of a pulse train with the modulation signal. Individual pulses of the pulse train include a first and second pulse portions that introduce and remove charge from the tissue. Moreover, the control unit varies a pause between the pulse portions until the synchronization of the stimulated neurons is minimized or falls below a predetermined threshold.

Provided is a transmission circuit which can adjust a difference between signal delay amounts in the amplitude path and the phase path with a low power consumption. An amplitude modulation section 15 amplitude-modulates a phase modulation signal outputted from a phase modulation section 14 with a voltage control signal provided by a regulator 13 to generate a transmission signal for an output of an antenna. Similarly, a feedback signal generation section 16 amplitude-modulates the phase modulation signal with the voltage control signal to generate a feedback signal FB. The signal FB is fed back to a delay adjustment section 12 and used for calculating and adjusting the difference between the signal delay amounts in the amplitude path and the phase path. The feedback signal generation section 16 is attained by a power amplifier having the same configuration as the amplitude modulation section 15 and a smaller circuit scale.

According to the BUCK amplitude-modulated high-frequency high-voltage electrostatic power supply and the working method thereof, after power frequency rectification filtering, BUCK chopping and high-frequency filtering are adopted, direct-current bus voltage with the amplitude modulated by the BUCK chopping is output, a series resonance inverter circuit composed of an IGBT full bridge, a capacitor and an inductor is connected, the resonance inverter circuit is controlled through pulses to work, and pulse current is output; and meanwhile, the two groups of series resonant inverter circuits work cooperatively, so that the pulse frequency of the pulse current is improved, and the amplitude-adjustable high-frequency high-voltage power supply is obtained. Through combination of the BUCK amplitude modulation technology and the high-frequency power supply technology, the power factor of a traditional silicon controlled rectifier amplitude modulation power supply is improved, the amplitude modulation range is widened, the application scene of the high-frequency power supply is further widened, and the reliability and adaptability of the high-frequency power supply to special working conditions are improved.