250 results about "Complex filter" patented technology

A feedback image rejection downconversion system is described, which can be used in low IF receivers with good performance and completely integrated. In the forward path of the system, quadrature mixers and complex filters are used for frequency downconversion and separation of the RF signal from the image signal. In the feedback path, a correlator, a gain mismatch estimator and two VGAs have been used to detect, estimate and compensate the amplitude and phase mismatch between the forward I and Q path signals. The whole system is self-tuned and can operate in both closed and open loop mode. A very high and robust image rejection ratio (over 60 dB) has been achieved.

Apparatus and methods are disclosed for detecting anomalies in microwave penetrable material that may be used for locating plastic mines or pipes underneath the ground. A transmitter is positioned at a plurality of different positions above the ground. A microwave signal is transmitted that is stepped over a plurality of frequencies. At each position, a plurality of reflections are received corresponding to each of the plurality of frequencies that were transmitted. A complex target vector may be produced at each position that contains complex values corresponding to magnitude, phase, and time delay for each of the plurality of reflections received at that location. A complex reference data vector may be produced, either based on predetermined values or based on data from the received plurality of reflections. A comparison is made between the complex target vector and the complex reference data vector to produce a channel vector. In one embodiment, an operator may be applied to the channel vector such as a complex filter matrix or to add a complex conjugate. A response signal is produced and anomalies are detected by variations in the response signal with respect to the plurality of positions.

A low power IF strip architecture suitable for Zero-IF (ZIF) or low-IF (LIF) radio receivers for filtering and amplifying a received signal. The apparatus includes a plurality of sequentially connected complex filter/amplifier stages. Each stage includes a complex filter having one or more poles and an automatic gain controlled amplifier (AGC). Each AGC may be feedback or feedforward with fixed minimum and maximum gains. Each stage further includes a control circuit that produces a gain control signal for controlling the amplifier gain within the fixed minimum and maximum gains as a function of a projected amplitude level. The received signal passes through multiple stages of filtering and controlled amplification to attenuate the interfering signal and amplify the desired signal. This is done at a restricted level in each stage such that the circuits in the stages operate at efficient power saving levels. The individual gain control signals from each stage are summed in a received signal strength indicator to provide the overall gain of the apparatus. The overall gain when taken with the amplitude of the apparatus output signal determines the original strength of the desired received signal.

A complex filter such as the channel select filter in a radio transceiver is implemented using a transconductance/C topology to benefit from the ability to tune such filters and thereby stabilize the output transfer function of the filter over variations in temperature, power supply voltage and process. The topology is based on an active R/C biquadratic topology to achieve the additional benefit of independently controlled stages. The problem created by the R in the output impedance is can be overcome by separately tuning the R value along with the transconductance/C ratio, by implementing the R as a transconductance amplifier having common mode feedback, or by implementing the transconductance amplifiers of the topology using Nauta transconductors, and unbalancing the common mode circuit of the Nauta transconductor to achieve a differential resistance that can be used to implement the R in the output impedance.

The invention relates to a device and a method for generating column vector beams. TEM00 model beams outputted by a laser is changed into linearly polarized light through a polarizer after the beams are reshaped and expanded by a beam expander and a diaphragm; the beams enter a spatial light modulator or a complex filter, and form an array through an analyzer; the beams pass through a 4f system consisting of a pair of Fourier transform lenses and aperture diaphragms; the beams are added into a phase retarder for phase modulation so as to generate TEM10 (or TEM01) model beams, and are synthesized to the column vector beams by using an interference system. The device and the method have the advantages of low requirement on incident beam, simple device, easy operation, high polarization degree of the output column vector beams and the like.

The invention discloses an RF (radio frequency) receiving front end with diversified gaining modes and capable of automatic tuning. The RF receiving front end comprises a low-noise amplifier, a frequency mixer, a complex filter and a time constant correcting circuit. The input end of the low-noise amplifier is connected with an input signal, and the output end adopts NC (numerical control) resistance as load to correct gains; the differential input ends of the I-path frequency mixer and the Q-path frequency mixer are respectively connected to the output end of the low-noise amplifier, and thedifferential output ends are respectively connected to the differential input end of the complex filter; the complex filter which adopts a multi-stage cascaded structure realizes the diversified gaining modes by the NC resistance, and meanwhile a time constant can realize tuning by controlling a capacitance array; and the output end of the time constant correcting circuit is connected with the correcting control word input end of the complex filter. By combining the current-mode low-noise amplifier, the passive frequency mixer and the active RC complex filter with each other, the RF receivingfront end has the advantages of low noise, high linearity, low power consumption, low cost and the like.

A complex filter with automatic tuning capabilities for filtering a complex signal is disclosed. The complex filter includes a first lowpass filter, a second lowpass filter, a plurality of resistors, an integrator, a comparator, and a digital unit. The complex filter includes an imaginary component and a real component. The integrator, the comparator and the digital unit forms a tuning circuit. The tuning circuit can generate a plurality of control signals to tune the complex filter to a predetermined frequency. The tuning circuit can be turned off after a predetermined period.

A method for correcting a time delay between at least two signals in ultrasound systems is provided. The ultrasound system comprises a beamformer processor comprising a summer coupled to the transducer array and configured for performing a complex operation on a first plurality of receive signals to generate a beamsum signal; wherein each of the receive signals comprise a corresponding beamforming delay and a complex filter coupled to the summer and configured to transform the beamsum signal to an analytical signal. The beamformer processor further comprises a plurality of correlator processors coupled to at least one respective transducer element and the complex filter, each correlator processor configured to calculate a correlation sum for at least one receive signal and at least one time delay estimator adapted to receive the correlation sum of at least one receive signal and configured to estimate the corresponding time delay using the correlation sum.

The invention relates to a method for preparing titanium dioxide/silicate mineral nano composites. The method comprises the following steps of: firstly, adding silicate minerals to a titanium tetrachloride solution to activate the silicate minerals and dissolve foreign ions; secondly, adding a certain alkaline solution to convert titanium ions to titanium dioxide hydrate precipitates and washing off other foreign ions to obtain titanium dioxide hydrate/silicate mineral complex filter cakes; and thirdly, adding the filter cakes to the titanium tetrachloride solution, adopting the acid environment of the titanium tetrachloride solution to realize dissolution of the titanium dioxide hydrates, secondary activation of the silicate minerals and low temperature crystallization and growth of nanotitanium dioxide on the silicate minerals and carrying out filtering, washing, drying and grinding, thus finally preparing the titanium dioxide/silicate mineral nano composites. The method has the following advantages that the method is simple and practical in steps; the reaction conditions are mild; the raw materials are simple and have low cost; and the method is suitable for large-scale production and can be beneficial to effective improvement of the photocatalytic efficiency of titanium dioxide.

An orthogonal mixer generates first I and Q signals by down-converting an RF signal. A complex filter has an asymmetrical frequency gain property between a positive frequency domain and a negative frequency domain, and generates second I and Q signals by suppressing image signals included in the first I and Q signals compared with desired signals. An orthogonal compensation circuit is located at a subsequent stage of the complex filter, and corrects the second I and Q signals to cancel a phase difference error and an amplitude error of the desired signals between the second I and Q signals. Further, a control circuit adjusts an element characteristic of the complex filter to cancel a phase difference error and an amplitude error of the image signals that appear in the second I and Q signals.

V An anomalous effect detector (100, 130, 300, 800, 830, 840, 900, 930) responsive to an influence of mind comprises a source of non-deterministic random numbers, SNDRN, (104, 134, 310), a phase-sensitive filter (108, 140, 170, 320), and a results interface (110, 160, 340). In some embodiments, the phase-sensitive filter comprises a complex filter (170). An artificial sensory neuron (802, 810, 820, 906) comprises a SNDRN. Preferably, several artificial sensory neurons (802, 906) are grouped in a small volume. An analog artificial sensory detector (800) comprises a plurality of analog artificial sensory neurons (802), an abstracting processor (804) and a control or feedback unit (806). Some embodiments include an artificial neural network (850). An artificial consciousness network (900) contains a plurality of artificial neural networks (902, 914). One of the artificial neural networks (914) comprises an activation pattern meta-analyzer. An artificial consciousness device comprises a cluster (936) of artificial consciousness networks, a sensory input device (932) to provide sensory input signals (933) to the input of one or more ANNs in ACD (930), and an output device (938).

The invention provides a transponder duplex multifrequency community antenna, which aims at solving the problem that the double antennas mutually influence with each other and have big influence on the electromagnetic characteristic of a base station in a varying magnetic field, the single antenna transponder needs a complex filter network, and the temperature characteristic of the antenna made of copper and aluminum pipe is poor. The key point of the invention is that: a resonance circuit formed by a resonant capacitance bank and an antenna body, and the resonant frequency thereof is F1; theantenna body is formed by two semicircular copper foils on a printed-circuit board, and is inductively coupled with the base station; the antenna body and a frequency F1 isolation module work under the frequency F2 and are served as a part of a transmitting antenna and/or a oscillation loop of the frequency F2; and an energy and received information extraction module extracts energy in a double-antenna extraction mode or a single-antenna extraction mode, and extracts information in a double-antenna extraction mode or a single-antenna extraction mode. The invention is applied to the transponder.

The invention belongs to the technical field of inorganic chemical industry, and particularly relates to a method and equipment for producing liquid sulfur dioxide through sulfur trioxide and sulphur. The method comprises the following steps: concentrated sulfuric acid or fuming sulphuric acid is fed into a reaction kettle, then liquid sulfur trioxide and liquid sulphur are fed into the reaction kettle, and stirring for reaction is performed; mixed gas generated through reaction enters a packing reaction tower filled with blocky solid sulphur for reaction, then mixed gas generated through reaction sequentially enters a purification tower and a pickling tower for purification absorption, and then is cooled to be liquid sulfur dioxide through a condenser. The equipment comprises the reaction kettle, wherein the reaction kettle, the packing reaction tower, the purification tower, the pickling tower, the condenser and a liquid sulfur dioxide storage tank are sequentially connected with one another; the reaction kettle is connected with a blow-down pump. Compared with the conventional pure-oxygen sulphur-burning method, the method has the advantages that multiple complex filtering equipment and oxygen generating equipment with relatively high cost are not required, the raw materials are cheap and easy to obtain, and are not required to be processed, the processes are simple, the technology is stable and reliable, the production running cost is reduced greatly, the product quality is high, and the method is suitable for industrial production of the liquid sulfur dioxide.

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.

A DC voltage offset correction circuit that provides for correction of a DC offset voltage of an output of a filter stage of a complex filter circuit includes a DC offset sensing device that is connected to an output of a filter stage of a complex filter to generate an offset presence signal indicating presence of the DC offset voltage at the output of the filter stage. The digital-to-analog converter applies a compensation signal to the output conditional on the offset presence signal. A programming register receives the offset presence signal to perform a binary search to generate a digital signal to force the digital-to-analog converter to apply the compensation voltage to the output of the filter stage. A filter controller sets the compensation voltage level in the programming register to match a programmed gain value of the filter stage.