30results about How to "Accurate waveform" patented technology

A dispersion compensation type optical signal receiving apparatus includes: an APD element for converting input signal light inputted from a transmission line into an electric signal; an amplifying device constituted with a preamplifier circuit and a limit amplifier circuit, which amplifies the electric signal converted by the APD element; an EDC IC for compensating the dispersion in the transmission line electrically; and a clock / data reproducing circuit for reproducing the clock and data signal contained in the input signal light, wherein there is provided a VOA for limiting the amplitude of the input signal light inputted to the APD element and an attenuation amount controlling circuit for controlling the attenuation amount of the VOA in accordance with the bias current of the APD element.

An LED driving circuit includes: (a) a current mirror circuit having N-channel MOS transistors whose respective gates are connected with each other, (b) a constant current source for supplying an LED driving current to an N-channel MOS transistor 4, (c) an LED connection terminal, connected with the N-channel MOS transistors, for connecting the LED, (d) an inverter and an input-terminal respectively for inputting, to a source of the N-channel MOS transistor, an ON / OFF signal for controlling ON / OFF of the LED, and (e) a peaking circuit, connected with a drain and source of the N-channel MOS transistor, for generating a peaking current used in peaking a current flowing into the LED. With this arrangement, it is possible to provide an LED driving circuit that easily realizes low current consumption and high-speed emission for the LED. With such an LED driving circuit, an optical transmitter for use in an optical fiber link can also be realized.

The invention discloses an angle measurement interface board card for an induction synchronizer, which comprises an induction synchronizer excitation module, an induction synchronizer preamplification module, a sampling and angle resolving module, a peripheral component interconnect (PCI) bus interface module and a power supply. The output end of the induction synchronizer excitation module is connected with the excitation input of an external induction synchronizer; the output end of the induction synchronizer is connected with the input end of the induction synchronizer preamplification module; the output end of the induction synchronizer preamplification module is connected with the input end of the sampling and angle resolving module; the output end of the sampling and angle resolvingmodule is connected with a bridge chip in the PCI bus interface module; the output of the bridge chip is connected with an external industrial personal computer through the PCI bus interface module; and the power supply is connected with the modules respectively. The angle measurement interface board card produces a few sine-wave higher harmonics and ensures accurate waveforms; and the interface board card can be conveniently connected with the industrial personal computer through a PCI bus, so that space is saved, and high anti-jamming capability is achieved.

The invention discloses a method for sampling high-frequency periodic signals, comprising the following steps: sampling input signals by using sampling signals, and storing data of the sampled input signals; counting frequencies of the input signals and the sampling signals so as to obtain frequency ratio of the input signals to the sampling signals; processing the data of the stored sampled input signals by using the frequency ratio of the input signals to the sampling signals so as to restore the input signals; and outputting the recovered input signals so as to display waveforms. By utilizing the method for sampling the high-frequency periodic signals provided by the invention, the high-frequency periodic signals can be effectively sampled and recovered by using low speed analog / digital, and the method is high in sampling precision and strong in controllability. The invention further discloses a system for sampling high-frequency periodic signals.

The invention provides an outer-locking ICP-type pipe-pressure sensor which is rational-structured, convenient and reliable to install, small-volume, and suitable for present space-compacted oil pipe pressure test. The foundational working principle of the sensor is the piezoelectricity effect; the sensor is suitable for dynamic pressure test; the said novel pipe-pressure sensor is composed of a sensor body, a shell, a modulating module. The sensor is mainly composed of a piezoelectricity crystal, an integral circuit amplifier, a signal output end and a stress surface; the sensor shell is composed of a shell, fastened bolts, locking screw caps, positioning blocks; the modulating module is composed of a constant flow resource and an external amplifying circuit. The novel pipe-pressure sensor provided by this invention, has sensibilities of 1000mV / N, 100m / N , measuring ranges of 5N, 50N; sensor of testing pipe diameter as diesel engine high-pressure oil pipe is Phi6-Phi8, the sensor of hydraulic oil pipe is no more than Phi 22, and Phi 35.

The invention relates to a synthetic method used for a radio frequency pulse in a magnetic resonance imaging (MRI) system. The synthetic method comprises procedures as follows: (1) the center frequency omega0 of the radio frequency pulse is calculated based on the magnetic field intensity of the MRI system and the location of a selective zone; (2) two orthogonal simulative sine or cosine signals of the frequency with one center frequency omega0 is sampled so as to acquire digital carrier signal sequence SC(n); (3) a digital baseband signal is calculated based on the bandwidth of a baseband signal; (4) the digital baseband signal is used for modulating a carrier and a digital radio-frequency signal is acquired; and (5) the acquired digital radio-frequency signal is downloaded onto the memory of a hardware to be stored; and after a trigger signal is sent by a pulse sequence controller, the digital radio-frequency signal is output after D / A conversion is performed. Compared with the prior art, the synthetic method can avoid complex hardware design and generate accurate waveform. In addition, the accuracy of the radio-frequency waveform is greatly improved; usability is good and the radio-frequency waveform is slightly affected by hardware error.

The present invention relates to a carrier-type SPWM waveform generation method based on a digital processor, comprising the following steps: (1) determining the modulation wave frequency and carrier ratio, and calculating the carrier frequency; (2) calculating the output pulse of each carrier cycle in the modulation cycle Width, establish a pulse width table; (3) At the beginning of each modulation cycle, update the duty cycle of the counter / timer / PWM generator according to the corresponding value of the pulse width table; (4) Output center-symmetrical high and low voltages according to the duty cycle Ping to get SPWM wave. The present invention can make full use of the hardware resources of the processor and the characteristics of the regular sampling method, pre-calculate the pulse width table, and update the comparison value of the counter / timer / PWM generator before each carrier period, and has the advantages of fast speed and accurate waveform Advantages: According to the difference of carrier frequency and carrier ratio, the pulse width table that meets the requirements can be easily calculated by using the formula.

The adaptive program-controlled receiving and processing device of the electromagnetic ultrasonic echo signal includes a signal conditioning module, the signal conditioning module is connected with the signal sampling and processing module; the signal sampling and processing module is connected with the processing chip; the processing chip is connected with the PC; the processing chip is connected with the The human-computer interaction module is connected; the processing chip is connected to the voltage control signal module; the processing chip is connected to the NAND FLASH; the processing method includes the following steps: 1) amplify the original signal waveform and send it to a high-speed analog-to-digital converter for sampling; 2) read the current signal Peak-to-peak value, the processing chip reduces the current amplification gain multiple or increases the current amplification gain multiple according to the analog-to-digital conversion result; 3) adjusts the amplitude of the electromagnetic ultrasonic echo signal through gain conversion, sends it to the analog-to-digital converter, and records each gain parameter at the same time , when it is displayed, it will be correspondingly converted to restore the original waveform; the electromagnetic ultrasonic echo signal can be received and digitally processed in a high-interference electromagnetic environment, ensuring the accuracy of the measurement.