40 results about "Elliptic filter" patented technology

The present invention relates generally to digital elliptic filters, and more particularly, but not exclusively to multi-layer digital elliptic filters and methods for their fabrication.

Disclosed is a complex elliptic filter having an order of three or higher which receives two differential signals that differ in phase from each other by 90 degrees are applied and outputs two differential signals that differ in phase from each other by 90 degrees. The complex filter circuit has internally at least two circuit blocks that include a capacitor connected in series with a coupler (gyrator). The complex filter is a third-order inverse Chebychev filter having an equiripple stopband of 40-dB attenuation amount. Alternatively, the coupler (gyrator) between elliptic capacitors is removed. Alternatively, the elliptic capacitors are made substantially equal to the capacitor arranged in parallel therewith. Alternatively, the gm value of an OTA and the capacitance value are each in an integral ratio represented substantially by a geometric progression of 2.

The invention relates to the field of signal generator, and specifically relates to an arbitrary waveform generator based on a PXIe bus. The generator comprises a waveform generation part and a waveform conditioning part. The waveform generation part comprises an FPGA and a crystal oscillator. The waveform conditioning part comprises a 16-bit DAC, an operational amplifier, an SPI program control amplifier, a filter circuit, an SPI program control DAC, a differential operational amplifier, and a subtracter. The generator employs the PXIe bus as a channel which is used by an upper computer for transmitting waveform data. The FPGA continuously process the waveform data transmitted by the upper computer in a waveform generation process, so as to guarantee the integrity of high-frequency signal quality. In a waveform conditioning process, the generator respectively employs a Bessel filter and an elliptic filter according to the frequency characteristics of signals and the difference of anti-noise capabilities, and meets the filtering requirements of different types of signals. For a signal with the amplitude being less than 50mV, a small signal processing branch circuit is designed, thereby guaranteeing that a signal with a small amplitude value cannot be flooded by noise. The generator employs a mode of internal and external synchronization adjustment for signal amplitude and bias, and guarantees the accuracy of a signal.

The invention relates to a method for designing an arbitrary duty ratio Michelson Gires-Touruois interferometer type unequal bandwidth optical interleaver. The method simplifies complicated transmissiThe invention relates to a method for designing an arbitrary duty ratio Michelson Gires-Touruois interferometer type unequal bandwidth optical interleaver. The method simplifies complicated transmissig a plurality of reflectors, and has wide application prospect in special wave filter, gain equalization and other fields.vantages for the situation of cascading a plurality of reflectors, and has wide application prospect in special wave filter, gain equalization and other fields.advantages for the situation of cascadinh utilization, high isolation, and the like for two paths of output spectrums. Particularly, the design method does not require programming for calculation, has simple calculation, represents betteradth utilization, high isolation, and the like for two paths of output spectrums. Particularly, the design method does not require programming for calculation, has simple calculation, represents betterteaver into sum and difference of two all-pass filters with adjacent exponent numbers. The unequal bandwidth optical interleaver designed by the method has the characters of high flatness, high bandwideaver into sum and difference of two all-pass filters with adjacent exponent numbers. The unequal bandwidth optical interleaver designed by the method has the characters of high flatness, high bandwidon of a multi-mirror GT cavity and the expression of a light wave electric vector in a reflection direction through z transform in a digital signal processing, calculates the expressions of transmission of a multi-mirror GT cavity and the expression of a light wave electric vector in a reflection direction through z transform in a digital signal processing, calculates the expressions of transmission functions of two paths of output ports of the optical interleaver on the basis, and obtains the cavity length and the arm length difference of the GT cavity, and the reflectivity of each mirror suron functions of two paths of output ports of the optical interleaver on the basis, and obtains the cavity length and the arm length difference of the GT cavity, and the reflectivity of each mirror surface of the GT cavity with design principle of an elliptic filter by a limit point value of a transfer function. Particularly, an even-order Michelson Gires-Tournois interferometer type optical interlface of the GT cavity with design principle of an elliptic filter by a limit point value of a transfer function. Particularly, an even-order Michelson Gires-Tournois interferometer type optical interleaver with definite exponent number can be designed to realize the arbitrary duty ratio optical interleaver throughby respectively decomposing two paths of transmission functions of the optical interleaver with definite exponent number can be designed to realize the arbitrary duty ratio optical interleaver throughby respectively decomposing two paths of transmission functions of the optical interl

The invention discloses a method for improving alignment signal processing accuracy based on adaptive correction processing. The method uses an elliptical side lobe filter to achieve better filtering effect; and uses a method for checking whether the alignment position is within the capture range , adaptively update the scan center and scan range, improve the adaptability of the alignment scan to the size of the spatial image, thereby improving the repeatability and scanning efficiency of the alignment scan; provide adaptive update threshold constant value and threshold filtering The processing method improves the adaptability of the alignment scan and the accuracy of the alignment scan.