40 results about "Elliptic filter" patented technology

The invention discloses a controllable electromagnetic mixed coupling coaxial cavity filter, comprising a conductor housing with two or more resonant cavities opened inside, the top of which is sealed by a conductor cover board and which is provided with a through hole; an input/output device penetrates through the through hole on the conductor hosing; bottoms of two or more conductor resonators are fixed to the conductor housing in contact with the guide housing to form short circuit; the conductor cover board opposite to the tope of the conductor resonator is provided with a tuning screw; an electromagnetic mixed coupling control component is arranged between two adjacent guide resonators which need electromagnetic mixed coupling. The invention accomplishes elliptic filter characteristic with a coaxial cavity filter only with main coupling path, which is provided with the following advantage of small volume, low cost, little insertion loss and nonsymmetrical response.

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.

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 present invention relates to a high frequency electromagnetic wave transmitter which comprises a frequency demultiplier, a gating switch, a filter, a transmission drive unit, a power amplification unit and an output end resonance loop which are in electric connection orderly. The output end resonance loop is connected with a transmission coil by a coupling transformer and forms an integral resonance loop together with the coupling transformer and the transmission coil. The transmitter uses the coupling transformer, temperature compensation, seven-step elliptic filter and a transistor C-class amplification circuit; compared with the prior art, the transmitter has the advantages of high transmission efficiency, good temperature characteristic, etc. The circuit design of the transmitter can be fit for various kinds of high frequency electromagnetic wave well logging tools with one or multiple transmission frequencies less than 15MHz and can work normally within a large temperature range between 25 DEG C and 150 DEG C.

The invention discloses a sub-1G radio frequency front-end circuit design based on RF energy detection and a parameter adjustment method based on RF energy detection. The procedure for adjusting parameter values of components in a second-order elliptic function low-pass filter on the basis of RF energy detection specifically comprises the following steps that a channel energy value is obtained; energy loss of a wireless signal on a transmission line and the communication distance between nodes are calculated; according to the calculated energy loss on the transmission line and the communication distance between the nodes, the parameter values of the components of the second-order elliptic function filter are adjusted. The stability and the reliability of the designed Sub-1G radio frequency front-end circuit are high, the parameter values of the components in the second-order elliptic function low-pass filter can be adjusted on the basis of RF energy detection, the purpose that the transmission line and the impedance of the load are matched with the impedance of a radio frequency source is achieved by replacing the actual electronic component values of the radio frequency circuit, and transmission at the maximum transmission power is achieved.

The invention discloses a laminated sheet type low pass filter for a CATV. The laminated sheet type low pass filter is small in size, low in cost and high in Q value and conductivity and is of an LTCC structure. The laminated sheet type low pass filter comprises a ceramic body and conductive coatings, wherein the ceramic body is formed by a plurality of layers of substrates made of high-frequency ceramic membranes, and the substrates are coated with the conductive coatings. Three laminated inductors formed by at least four sets of laminated sheets coated with three semi-elliptic or semicircular independent conductive coatings are arranged in the ceramic body. According to the laminated sheet type low pass filter for the CATV, the LTCC technology multi-layer structure is adopted to manufacture the seven-order low pass filter with three transmission zeros, and an original elliptic filter is adopted to improve the circuit characteristic through coupling between the laminated spiral inductors. The size of the laminated sheet type low pass filter is 3.2 mm*2.5 mm*1.0 mm, the LTCC technology is adopted, the cost is low, and mass production can be achieved. In addition, the conductive coatings on every two substrates in the laminated inductors of the low pass filter are connected in parallel, the sectional area of a coil is increased, and therefore the high frequency quality factor of the filter is improved.

Disclosed are a low-power high-frequency ultrasonic power source and an achieving method thereof. According to the device, an experimental mode of combination of software and hardware is adopted, and a hardware part is mainly formed by a power source operation panel, an ultrasonic power source circuit, an ultrasonic vibrator and an inductor matched with the ultrasonic vibrator. The operation panel is structurally provided with a power switch key, an indicating lamp of the power switch key, a reset key, an indicating lamp of the reset key, a frequency selection key, an indicating lamp of the frequency selection key, a mode selection key, an indicating lamp of the mode selection key, a power selection key and an indicating lamp of the power selection key. The power source circuit is mainly formed by a power switch circuit, a reset circuit, a crystal oscillation circuit, a key circuit, a state display indicating lamp circuit, an elliptic filter circuit, a mode and power chopper switch circuit, a power amplification circuit and a matching network circuit. A frequency generating module, a mode setting module, a power selection module, a matching inductance switching control module and a control module of the indicating lamps of the device are achieved by software programming.

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 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 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 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 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 bandwidth 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 better advantages for the situation of cascading a plurality of reflectors, and has wide application prospect in special wave filter, gain equalization and other fields.

The invention provides a fractional order elliptic filter design method of an amplitude non-attenuation equilibrium phase. The method specifically comprises the following steps: firstly, initializingan algorithm, designing an all-pass filter of which the amplitude is attenuated, converting the order of the elliptic filter into any positive real number from an integer, and then introducing an amplitude non-attenuation reverse filter to obtain an amplitude non-attenuation equilibrium phase; estimating that the error signal amplitude is not attenuated and the phase is a negative phase, and effectively compensating the phase of the fractional order analog filter. According to the fractional order elliptic filter design method of the amplitude non-attenuation equilibrium phase, the order adjustment of the filter becomes more flexible, due to the introduction of the reverse filter, the phase delay of the filter is effectively compensated, the linearity of the elliptic filter is improved; meanwhile, the amplitude of the filter is not attenuated, therefore, the steep transition zone characteristics of the elliptical filter are not changed, the comprehensive performance of the filter is improved, and the method has good engineering practicability.

The invention is a quasi-elliptic filter characteristic frequency selection surface, an ultrathin novel frequency selection surface with quasi-elliptic filter characteristic, based on substrate integrated waveguide cavity cascading technique, and the structure is made on a multilayer substrate formed by laminating three layers of microwave plates and having four metal surface layers and three medium layers, where the top and bottom metal surfaces are made with periodical square annular slots of the same size. And the intermediate metal surface is made with periodical square annualr slots of the other size which coincides the centers of the square annular slots on the top and bottom surfaces, three medium layers are filled in between the four metal surface layers, and a series of metalized through holes are arranged at regular intervals around each periodical square annular slot unit on the ready-laminated multilayer substrate so as to form a substrate integrated waveguide cavity equivalent to traditional metal cavity. As compared with common SMD or slot type multiscreen cascaded frequency selection surface, it first implements quasi-elliptic filter performance with high selectivity.

The invention discloses a single reactance compensation magnetic coupling resonance type wireless power transmission broadband E-type power amplifier. The working process of the single reactance compensation magnetic coupling resonance type wireless power transmission broadband E-type power amplifier is as follows: an input signal (1) passes through an input matching circuit (2) and an input reactance compensation circuit (3); a gate bias power supply (4) is connected to the front end of a power tube (6) through a power supply filter circuit (5); a feedback circuit (7) is connected to two endsof the power tube (6) in parallel; a drain power supply (8) is connected to the rear end of the power tube (6) through a power supply filter circuit (9); and the output signal of the power tube (6) passes through an output reactance compensation circuit (10), an output matching circuit (11), and a low-pass elliptic filter circuit (12). Compared with the traditional single frequency point E-type power amplifier, ideal output power and efficiency can be kept on a relatively wide frequency band; the system output frequency is convenient to adjust; only the output signal frequency of a signal generation circuit needs to be adjusted; and furthermore, due to adoption of the low-pass elliptic filter circuit, the filter property of a broadband E-type power amplifier load network is improved.

The invention discloses an inverse Chebyshev active low-pass filter circuit with a double-operational-amplifier elliptic function. The circuit comprises a signal input end Vs, a signal output end Vo and an input and output signal common end GND, and is characterized by further comprising a resistor Rq1, a resistor Rq2, a resistor Ra, a resistor Rb, a resistor Rd, a resistor Ri, a resistor Ro, a capacitor Ca, a capacitor Cb, an operational amplifier U1A and an operational amplifier U1B, and one end of the resistor Rq1, one end of the resistor Ri and one end of the capacitor Ca are connected to a node p1, which serves as the input end which is connected to an input signal Vi; the other end of the resistor Rq1, the other end of the capacitor Ca, one end of the resistor Rq2, one end of the resistor Ra and the in-phase input end of the operational amplifier U1A are connected to a node p2; and the other end of the resistor Rq2 is connected to the input and output signal common end GND. The circuit is good in symmetry, stable in performance and easy to design and use, one to two operational amplifiers are saved compared with a 3 or 4 operational amplifier state variable elliptic function filter, power consumption is reduced, the size of the circuit is reduced, and the cost of the filter and the circuit is reduced.

The invention provides a bandpass frequency selective surface structure based on an antenna, a filter and an antenna. The structure comprises a frequency selection unit which consists of a first radiation patch, a first dielectric plate, a first metal floor, a second dielectric plate, a resonance layer, a third dielectric plate, a second metal floor, a fourth dielectric plate and a second radiation patch; the projections of first slots formed in the first metal floor fall on the first radiation patch; the projections of second slots formed in the second metal floor fall on the second radiation patch; the resonance layer is composed of a first microstrip and a second microstrip which are orthogonal to each other; the projections of the first slots on the resonance layer and the projections of the second slots on the resonance layer are located at two sides of the first microstrip; the length direction of the first slots and the length direction of the second slots are consistent with the length direction of the first microstrip. The structure generates four transmission extreme points and two transmission zero points in total, and has stable quasi-elliptic filter response and high selectivity, good angle stability and low profile.

The invention belongs to the field of integrated circuit design, and relates to a four-order current type elliptical filter structure based on OTA-C. The filter is composed of four grounding capacitors and six single-ended input OTA, and comprises two current signal input ends Iin and a current signal output end I'out. From the perspective of mathematical derivation, an analytical synthesis method is adopted, and poles of the four-order current type elliptic filter are determined through a transfer function. And the frequency characteristic of the circuit can be changed only by changing various coefficient values of a circuit transfer function without changing the circuit topology, so that four filtering functions of low-pass, high-pass, band-pass and band-stop are realized respectively. As the OTA can adjust the transconductance value through the external bias current, the elliptical filter designed by the invention has good in-band selectivity and also can realize adjustable functions.

A differential elliptic filter circuit includes: a differential amplifier, feedback and feedforward paths. An upper pair and a lower pair of inverting feedback paths couple a corresponding one the differential signal outputs of the amplifier to an inverting one of a pair of inputs of the amplifier, to provide two complex conjugate poles, and establish upper and lower virtual grounds at the amplifier inputs. Upper and lower inverting feedforward paths couple corresponding passive nodes of the upper and lower pairs of inverting feedback paths to respectively the lower and upper virtual grounds to provide two zeros of the circuit. The upper and lower non-inverting feedforward paths couple an upper and lower one of a pair of differential signal inputs of the circuit to respectively the upper and lower virtual grounds to enable positioning of the two zeros of the circuit on an imaginary axis of a pole-zero plot.