47results about How to "Eliminate DC component" patented technology

The invention discloses a 9B / 10B coding method suitable for low-pass and band-pass channels, which is used for coding a 9-bit source sequence set into a 10-bit target sequence set, and the 10-bit target sequence set does not contain balance sequences' 1010101010 'and' 0101010101 '. The 9-bit source sequence set comprises a first type of 9-bit source sequence set, a second type of 9-bit source sequence set and a third type of 9-bit source sequence set. The first type of 9-bit source sequence set only contains 9-bit source sequences with difference values of 1 and-1, and after one-bit data '0' or '1' is inserted into the same position of each sequence in the first type of 9-bit source sequence set, the sequence is coded into a 10-bit target balance sequence; the second type of 9-bit source sequence set selectively only contains 9-bit source sequences with the difference value of 3 or only contains 9-bit source sequences with the difference value of-3, one bit of data '0' or '1' is inserted into each sequence in the second type of 9-bit source sequence set, and a pair of 10-bit target unbalanced sequences with the difference value of + / -2 is coded.

The invention discloses a method and system for balancing the midpoint potential of a two-stage three-level three-phase four-wire energy storage converter, comprising: according to the low voltage in the three-level Buck / Boost circuit in the energy storage converter Side inductor current reference value i Lref , control the three-level Buck / Boost circuit to work in Boost mode or Buck mode; refer to Δu according to the midpoint potential ref The difference from the midpoint potential offset Δu is used to adjust the duty cycle of each switch in the Buck / Boost circuit in Boost mode or Buck mode, so that the total DC bus voltage is constant and the midpoint potential is balanced. The invention has the advantages of constant total voltage of the DC bus, balanced midpoint potential, and improved operation stability of the converter.

The invention belongs to the technical field of micro-displacement sensors, and specifically relates to a two-dimensional micro-displacement sensor based on a four-quadrant grating and a detector, including a first laser, a second laser, a first collimator lens, a second collimator lens, a movable grating, four-quadrant grating, and four-quadrant detector, the first laser and the second laser are respectively arranged directly above the first collimating lens and the second collimating lens, and the first collimating lens and the second collimating lens A movable grating is arranged under the lens, and an X-axis four-quadrant grating and a Y-axis four-quadrant grating are arranged under the movable grating, and a first Four-quadrant detector, the second four-quadrant detector. The present invention generates four-channel signals through a four-quadrant grating and a detector for differential, which is beneficial to subsequent high-magnification subdivision, can eliminate background noise and DC components, and improve the resolution and precision of micro-displacement detection. The invention is used for the measurement of micro-displacement.

A method and device for correcting a DC offset of a zero-IF receiver, the method comprising the following steps: (a) before the zero-IF receiver is connected to a radio frequency switch, an initial DC offset DC-OFFSET is estimated to obtain an initial DC -After the estimated value of OFFSET, the zero-IF receiver is connected with the radio frequency switch and starts to receive data; (b) using the initial estimated value of DC-OFFSET to compensate the received data; (c) to compensate the received data Estimating the starting position of the training sequence to obtain the offset of the actual position of the training sequence relative to the expected position; (d) performing joint estimation of the channel impulse response and DC-OFFSET to obtain the estimated value of DC-OFFSET; (e) using the DC -OFFSET estimated value for DC-OFFSET compensation of received data. The device includes a main control unit and a baseband processing unit. The main control unit controls the baseband processing unit to first perform initial DC-OFFSET estimation, and then receive data to perform initial DC-OFFSET compensation before performing subsequent compensation.

The invention provides an optical signal receiving device and photoelectric detection equipment. The optical signal receiving device comprises a current-voltage conversion unit, a filtering unit and asignal acquisition unit, wherein the current-voltage conversion unit is used for receiving an optical signal and converting the received optical signal into a voltage signal, and the voltage signal comprises an alternating current component, a direct current component and a noise component; the filtering unit is connected with an output end of the current and voltage conversion unit and used foracquiring the direct current component and the noise component through low-pass filtering; and the signal acquisition unit is connected with the output end of the current-voltage conversion unit and an output end of the filtering unit, and acquires the alternating current component through performing a differential operation on the voltage signal outputted by the current-voltage conversion unit and the direct current component and the noise component which are outputted by the filtering unit. The optical signal receiving device is low in cost and simple in structure, increases the stability and reliability of the output signal and improves the accuracy of the photoelectric detection equipment.

The invention relates to a zero-phase on-line DC removal filter for a road noise active control system. The zero-phase on-line DC removal filter comprises a first delayer, wherein the first delayer isused for delaying an input signal x(n) by fs unit lengths to obtain a delay signal x(n-fs); a first subtracter, taking an input signal x (n) and a delay signal x (n-fs) as input and subtracting the input signal x (n) and the delay signal x (n-fs) to obtain an output difference signal w (n); a first adder, taking the difference signal w (n) and the intermediate delay signal r (n-1) as input and adding the input to obtain an intermediate signal r (n); a second delayer, used for delaying the intermediate signal r (n) by one unit length; and a first multiplier, used for dividing the intermediatesignal r (n) by the sampling frequency fs to obtain an average value of the input signal x (n), and a second subtracter, used for subtracting the input signal x (n) from the average value to obtain adirect-current-removed output signal y (n). Compared with the prior art, the zero-phase on-line DC removal filter can realize online DC component removal, does not introduce phase change, and is suitable for online removal of DC components in active noise control.

The invention discloses a zero-IF receiving device and method. The device comprises: a first combiner switch, a first branch switch, a plurality of filters, a second combiner switch, a second combiner switch, and a first amplifier , the first amplifier, the first programmable attenuator, the second amplifier, the first power divider, the first integrated phase-locked loop, the first quadrature demodulator, the second quadrature demodulator, the first relay, the second relay, second power divider, third power divider, first filter, second filter, third filter, fourth filter, first analog-to-digital converter, second analog-to-digital converter, CPLD, The first digital-to-analog converter, the second digital-to-analog converter, the first operational amplifier, and the second operational amplifier, the present invention adopts quadrature demodulation and DC cancellation technology, with low complexity, high reliability, low cost and good stability , the receiving frequency is wide, the anti-interference ability is strong, and the DC component can be effectively eliminated.