Entries |
Document | Title | Date |
20080218254 | Reduced jitter amplification methods and apparatuses - Apparatuses, circuits, and methods to amplify signals with reduced jitter are disclosed. Embodiments generally comprise amplifiers coupled with apparatuses that adjust peak frequencies of the amplifiers to reduce jitter. In many system and apparatus embodiments, the frequency gain boosters receive one or more feedback signals derived from input signals applied to the amplifiers. The frequency gain boosters generally respond to the feedback signals by manipulating or controlling active loads coupled to the amplifiers. In controlling the active loads, the frequency gain boosters generally cause the active loads to peak at frequencies at or near the input signals, the result being attenuated jitter in an output signal of the amplifier. | 09-11-2008 |
20080218255 | Filter Characteristic Adjusting Apparatus and Filter Characteristic Adjusting Method - There is provided a filter characteristic adjusting apparatus and a filter characteristic adjusting method which can avoid an increase in circuit scale of the filter characteristic adjusting apparatus, and can speedily adjust a characteristic frequency of the filter to a desired frequency. When performing characteristic adjustment for the filter, the test signal generation unit ( | 09-11-2008 |
20080252365 | APPARATUS AND METHOD FOR TUNING CENTER FREQUENCY OF A FILTER - A method for tuning a filter is provided. The method includes: enabling a VCO circuit, wherein at least a portion of the VCO circuit is selected from the filter; generating an oscillation signal by the VCO circuit according to a driving signal; comparing the oscillation signal with a reference signal and generating a comparison result; and adjusting the driving signal according to the comparison result. | 10-16-2008 |
20080258806 | Phase-Locked Loop Based Controller for Adjusting an Adaptive Continuous-Time Filter - A direct conversion radio-frequency (RF) receiver includes a controller and an adaptive continuous-time filter. The adaptive continuous-time filter receives a multiple-bit control signal generated by the controller to adjust a characteristic of the continuous-time filter. The controller generates the multiple-bit control signal in response to process variation in the semiconductor material used to implement the controller and the adaptive continuous-time filter. A method for tuning an adaptive continuous-time filter comprises determining a RC time constant, converting the RC time constant to a digital word, comparing a select bit of the digital word to a respective bit of a predetermined reference word to generate a control bit, applying the control bit to an adjustable element to modify the RC time constant, repeating the determining, converting, comparing and applying steps until the control bits generate an output word and providing the output word to the adaptive continuous-time filter. | 10-23-2008 |
20080272838 | Self-Calibration of Continuous-time Filters and Systems Comprising Such Filters - A continuous-time filter system comprises a master control unit and a slave unit with one or more slave filters. The master control unit includes an integrator having circuit elements which match those elements of the slave filter that define the slave filter's time constant. The master control unit further includes a voltage comparator connected to an output of the integrator, the voltage comparator providing an output frequency signal, and a phase frequency comparator providing a control signal as an output signal, the phase frequency comparator receiving said output frequency signal and a reference frequency signal as input signals. The slave unit includes said at least one slave filter, the slave filter having a control signal input for receiving said control signal thus allowing to calibrate the slave filter's transfer function by influencing the slave filter's time constant. | 11-06-2008 |
20090021296 | SAMPLING FILTER AND RADIO COMMUNICATION APPARATUS - There are provided a sampling filter that enables a filter characteristic to be adjusted flexibly, and a radio communication apparatus equipped with this sampling filter. A sampling filter apparatus ( | 01-22-2009 |
20090027115 | CUTOFF FREQUENCY ADJUSTING METHOD, GmC FILTER CIRCUIT AND SEMICONDUCTOR DEVICE - A cutoff frequency adjusting method adjusts a cutoff frequency of a GmC filter circuit which has a capacitor and an Operational Transconductance Amplifier (OTA) circuit with a controllable Gm value. A Gm value of the OTA circuit is detected based on a voltage of the capacitor which is charged by an output of the OTA circuit, and a cutoff frequency of the GmC circuit is set to a desired value by controlling the Gm value of the OTA circuit constant based on the detected Gm value. | 01-29-2009 |
20090039955 | VARIABLE RESISTOR, FILTER, VARIABLE GAIN AMPLIFIER AND INTEGRATED CIRCUIT USING THE VARIABLE RESISTOR - A variable resistor formed on a silicon substrate, and changing a resistance value between an input terminal and an output terminal, includes a plurality of first resistors each having one end connected in common to the input terminal, and each having other end, a plurality of second resistors each having a resistance value smaller than the first resistors, and each having one end connected to the other end of any one of the first resistors, and a switch group interposed between the input terminal and the output terminal, and selecting one from the first resistors, and further, selecting at least one from the second resistors connected to the other end of the selected first resistor. | 02-12-2009 |
20090051420 | INTRINSIC RC POWER DISTRIBUTION FOR NOISE FILTERING OF ANALOG SUPPLIES - Analog supply for an analog circuit and process for supplying an analog signal to an analog circuit. The analog supply includes a noise filter having a variable resistor, and a control device coupled to adjust the variable resistor. The control device is structured and arranged to set the resistance of the variable resistor to maximize noise filtering and optimize performance of the analog circuit. | 02-26-2009 |
20090072896 | Equalizer Filters Including a Low-Pass Filter Unit and an Equalizer Having a Group Delay Control Unit and Related Methods - Provided is a filter used for an equalizer, the filter including: a first low-pass filter unit receives an input signal and performs low frequency band filtering on the input signal; and an equalization unit that receives an output signal from the first low-pass filter unit. The equalization unit may comprise a plurality of serially connected biquad low-pass filter units, and may control a value of a capacitor that is used to control a group delay value that is generated during equalization. Thus, the filter can compensate for group delay without including a separate all pass filter, thereby reducing surface area and power consumption. | 03-19-2009 |
20090091377 | INTEGRATED SYSTEM AND METHOD FOR MULTICHANNEL NEURONAL RECORDING WITH SPIKE/LFP SEPARATION, INTEGRATED A/D CONVERSION AND THRESHOLD DETECTION - A CMOS integrated circuit for multi-channel neuronal recording with twelve true-differential channels, band separation and digital offset calibration. The recorded signal is separated into 2 bands: a low-frequency, local field potential (LFP); and high-frequency spike data. Digitally programmable gains for the LFP and spike bands are provided. A mixed-signal front-end processor for multi-channel neuronal recording is also described. It receives twelve differential-input channels of implanted recording electrodes. A programmable cutoff HPF blocks DC and low frequency input drift at about 1 Hz. The signals are band-split at about 200 Hz to low-frequency local field potential (LFP) and high-frequency spike data (SPK), which is band limited by a programmable-cutoff LPF. The analog signals are converted into digital form, and streamed out over a serial digital bus at up to 8 Mbps. A special interface system incorporating an embedded CPU core in a programmable logic device accompanied by real-time software allows connectivity to a computer host. | 04-09-2009 |
20090096515 | FILTER ADJUSTMENT METHOD AND FILTER ADJUSTMENT APPARATUS AS WELL AS FILTER CIRCUIT - The object is to provide a filter circuit as well as a filter adjustment method and a filter adjustment apparatus that can adjust the characteristics of an analog filter by use of a simple configuration. | 04-16-2009 |
20090108927 | FILTER ADJUSTING CIRCUIT - A filter adjusting circuit, has: a filter circuit which has a circuit configuration operating as an n-th order filter including n (n≧1) integrators and can switch a connection of the circuit configuration to operate as a circuit equivalent to the n integrators; a signal generating circuit that outputs a first signal having a predetermined reference frequency to the filter circuit, and outputs a second signal having the reference frequency; a phase comparator that compares a phase of a third signal and a phase of the second signal and determines a phase shift between the signals, the third signal being obtained by processing the first signal in the filter circuit and outputted from the filter circuit; and a control circuit controls the filter circuit. | 04-30-2009 |
20090167426 | INTEGRATED CIRCUIT INCLUDING FILTER CIRCUIT ARRANGEMENT - An integrated circuit includes a filter circuit that has at least one active device, wherein the active device has adjustable transconductance. | 07-02-2009 |
20090179696 | TIME CONSTANT AUTOMATIC ADJUSTING CIRCUIT, FILTER CIRCUIT SYSTEM, AND METHOD OF AUTOMATICALLY ADJUSTING TIME CONSTANT - A time constant automatic adjusting circuit comprises: a filter circuit varying a phase of an clock signal to be input so as to output the clock signal; a phase comparison circuit comparing a phase of an output signal of the filter circuit with the phase of the clock signal, and outputting a predetermined voltage when the phase of the output signal and the phase of the clock signal are the same; at least three comparators comparing the output voltage with a plurality of different voltages; an up-down counter counting a number of output bits of either one of the at least three different voltages in accordance with an output result of the comparators; and a control circuit varying the time constant of the filter circuit in accordance with the number of output bits counted by the up-down counter. | 07-16-2009 |
20090206923 | FILTER SWITCHING DEVICE AND FILTER SWITCHING METHOD - A filter switching device includes a first buffer amplifier, a first characteristic resistor with one terminal connected to the output of the first buffer amplifier, first and second filter circuits connected in parallel to the other terminal, the first filter circuit including a first relay and a first low-pass filter, the second filter circuit including a second relay and a second low-pass filter, a third filter circuit connected to the output of the first buffer amplifier, having a second buffer amplifier and a second characteristic resistor connected between the output of the second buffer amplifier and a third low-pass filter, and a multiplexer connected between the first, second, and third filter circuits and a third characteristic resistor selectively connecting the first, second, or third filter circuit to the third characteristic resistor. | 08-20-2009 |
20090289699 | Output conductance automatic regulation circuit of differential current output type circuit and filter circuit - Output conductance of a differential current output type circuit constituting a filter body ( | 11-26-2009 |
20090289700 | FORWARDED CLOCK FILTERING - Some embodiments include a tunable bandpass filter to provide a filtered output signal; a circuit portion to provide an output signal in response to the filtered output signal; a comparator circuit to provide a comparison signal in response to the output signal from the circuit portion; and a feedback circuit to tune the tunable bandpass filter in response to the comparison signal provided by the comparator circuit. Other embodiments are described and claimed. | 11-26-2009 |
20090302933 | Tuning methods and apparatus for inductively coupled power transfer (ICPT) systems - A method is provided for controlling a resonant circuit ( | 12-10-2009 |
20090315619 | CIRCUIT FOR ADJUSTING CUTOFF FREQUENCY OF FILTER - A cutoff frequency adjusting circuit includes a filter circuit ( | 12-24-2009 |
20100060350 | Adaptive Filtering System for Patient Signal Monitoring - A system provides a high quality, and intuitive multi-band filter that adapts when noise frequencies or noise amplitudes change. A system for adaptively filtering patient monitoring signals, comprises a filter controller for adaptively determining the number of, and individual filter bandwidth of, multiple adaptive signal filters to be used in filtering multiple bandwidths within an encompassing signal filtering bandwidth. The filter controller does this in response to, (a) noise data indicating noise source frequencies and (b) configuration data determining medical signal or noise source characteristics, to provide programming data for programming a plurality of adaptive signal filters. The system includes multiple adaptive signal filters individually having a filtering bandwidth and filtering characteristic programmable in response to received programming data. A noise detector automatically identifies a noise component in a received patient monitoring signal and generates the noise data. | 03-11-2010 |
20100066442 | Method and Apparatus for Tunable Current-Mode Filtering - According to the teachings presented herein, a tunable current-mode filter is implemented using two or more tunable filter stages in cascade connection. For example, a number of tunable filter stages corresponding to a desired filter order are included in the filter in cascade connection. Use of the current-mode filter simplifies circuit design, particularly in communication transmitter applications, and avoids current-to-voltage conversions needed when voltage-mode filters are used in current-mode signal processing chains. A method and circuit to tune and calibrate the frequency response of the filter are disclosed as well. | 03-18-2010 |
20100156525 | Method and System for Tuning Precision Continuous-Time Filters - Described embodiments provide a method for calibrating a continuous-time filter having at least one adjustable parameter. A square-wave signal is filtered by a continuous-time filter having a cutoff frequency less than fs. The filtered signal is quantized at the rate fs. An N-point Fourier transform is performed of the quantized signal into N real output values and N imaginary output values. At least one of the real output values are accumulated to form a real output signal and at least one of the imaginary output values are accumulated to form an imaginary output signal. The real and imaginary output signals are summed to form an output signal, which is then squared. The squared output signal is compared to a comparison value. At least one parameter of the continuous-time filter is adjusted based upon the comparison. The steps are repeated until the squared output signal is approximately the comparison value. | 06-24-2010 |
20100188143 | Bias circuit, and gm-C filter circuit and semiconductor integrated circuit each including the same - A bias circuit, includes: a first positive channel Metal Oxide Semiconductor transistor forming a first current source; a second positive channel Metal Oxide Semiconductor transistor composing a current mirror circuit of the first positive channel Metal Oxide Semiconductor transistor and forming a second current source; a first negative channel Metal Oxide Semiconductor transistor having a drain to which a current is supplied from the first current source; a second negative channel Metal Oxide Semiconductor transistor composing a current mirror circuit together with the first negative channel Metal Oxide Semiconductor transistor, and having a drain to which a current is supplied from the second current source; and a resistor connected between a source of the second negative channel Metal Oxide Semiconductor transistor and a ground; wherein a resistance component for gm adjustment is connected between a source of the first negative channel Metal Oxide Semiconductor transistor and the ground. | 07-29-2010 |
20100219883 | Active Filter Calibration Method and Apparatus - An example bandpass filter calibration system includes a MUX, first and second signal sources coupled to inputs of the MUX, a bandpass filter coupled to an output of the MUX, a rectification circuit including a plurality of rectifiers having a corresponding plurality of rectifier outputs coupled to an output of the bandpass filter, a summer having a plurality of inputs coupled to the plurality of rectifier outputs, a low pass filter coupled to an output of the summer, an ADC coupled to an output of the low pass filter, and a calibration processor unit coupled to an output of the ADC. The calibration processor unit controls the MUX to selectively apply the first signal source and the second signal source to the bandpass filter and calibrates the bandpass filter by a least one of increasing filter center frequency and decreasing filter center frequency of the bandpass filter. | 09-02-2010 |
20100244943 | FILTER SHAPING USING A SIGNAL CANCELLATION FUNCTION - A signal filter and accompanying methods. In one embodiment, the filter includes a first mechanism for receiving a first signal. A second mechanism employs one or more modified representations of the first signal to cancel one or more frequency components of the first signal, yielding an output signal in response thereto. In a more specific embodiment, the first mechanism includes a splitter for receiving the first signal and splitting the first signal onto a first path and a second path. The second mechanism further includes one or more delay modules and one or more phase shifters in the first path and/or the second path. One or more controllable amplifiers are optionally included in the first path and/or the second path. The one or more delay modules, phase shifters, or amplifiers are responsive to one or more control signals from a controller. The controller is adapted to modify behavior of the second mechanism so that the filter is characterized by a desired frequency response. | 09-30-2010 |
20100244944 | Phase Locked Loop-Based Tuning Adjustable Filter - This disclosure relates to phase locked loop based frequency tuning of an adjustable filter. | 09-30-2010 |
20100244945 | Calibration of Adjustable Filters - A filter controller. In one embodiment, the filter controller includes a first mechanism for providing an input signal to an adjustable filter. A second mechanism measures a response of the adjustable filter to the input signal and provides a second signal in response thereto. A third mechanism sets one or more parameters of the adjustable filter in response to the second signal. In a more specific embodiment, the adjustable filter includes one or more sub-filters, such as a canceller filter, which may be any filter that employs one or more portions or versions of a signal to selectively cancel one or more portions or versions, such as frequency components, of the same signal. | 09-30-2010 |
20110025410 | Resonant Circuits - Embodiments of the invention relate to resonant circuits; particularly but not exclusively the embodiments relate to resonant circuits in RPID (radio frequency identification) responsive to a wide frequency range. A controllable electric resonator comprising an inductor coupled to a first capacitor to form a resonant circuit, the resonator further comprising a controllable element, a second capacitor controllable coupled across said first capacitor by said controllable element, and a control device to control said controllable element such that a total effective capacitance of said first and second capacitor varies over a duty cycle of an oscillatory signal on said resonator. | 02-03-2011 |
20110025411 | Apparatus and Method for Tuning a GM-C Filter - An apparatus to control a tuneable Gm-C filter, including and a filter that can be reconfigured as a free running oscillator by toggling the feedback sign of an output amplifier ( | 02-03-2011 |
20110037515 | Op-R, a solid state filter - The device described herein proposes an electronic active filter void of capacitors and inductors. The circuit utilizes only operational amplifiers (OP-Amp) and resistors, hence the name Op-R. Although capable of being constructed of lumped circuit elements this filter is intended for integrated circuit (IC) applications. Filtering of signals can be accommodated from dc through the UHF frequency range depending on the selected op-amp ICs. Low pass, band pass, high pass, as well as band reject frequency responses are achievable. Although the circuits described herein are single input-single output, multiple inputs and outputs present no difficulty, being limited only chip space. Temperature and production spread variations are also considered within the realm of tunability. | 02-17-2011 |
20110109380 | ACTIVE ANALOG FILTER HAVING A MOS CAPACITOR DEVICE WITH IMPROVED LINEARITY - An active analog filter ( | 05-12-2011 |
20110148514 | FREQUENCY VARIABLE COMPOSITE RESONANCE CIRCUIT - A composite resonance circuit is provided of which the resonance frequency range can be set with greater degrees of freedom with the peak frequency of the resonance characteristic curve of a resonance unit having good linearity and the resonance sharpness Q-factor being kept within a desired range. In the composite resonance circuit according to the present invention, first and second relay circuits are respectively connected between the resonance unit and first and second phase shift circuits that shift an input frequency signal by different phases. Hence, the resonance frequency range can be set by setting the gains and impedances of the first and second relay circuits according to its use, without changing resonance elements or the like of the resonance unit. | 06-23-2011 |
20110148515 | QUASI-RESONANT COMPOSITE RESONANCE CIRCUIT - A composite resonance circuit is provided of which the resonance frequency is variable over a wide frequency range without changing the circuit constant of a non-resonant element having no resonance frequency. The composite resonance circuit comprises an input terminal; a resonance unit having first and second ports and quasi-resonating in response to AC signals respectively supplied to these ports; and phase shift circuits that perform different phase shifts on an AC signal supplied to the input terminal and supply first and second shifted signals subjected to the phase shift respectively to the first and second ports. The resonance unit is an impedance circuit that has at least four input terminals forming the first and second ports and that generates a quasi-resonant peak current under non-zero reactance in response to the first and second shifted signals coming in via the first and second ports. The quasi-resonant peak current is variable according to the frequency and phase shift quantities of the AC signals. Namely, the resonance frequency can be made to be variable. | 06-23-2011 |
20110187448 | Wideband analog bandpass filter - A wideband bandpass filter includes an RF input terminal, an RF output terminal, a plurality of electrically tunable coupling capacitors coupled in series between the RF input and output terminals, and a plurality of resonating circuits each including an electrically tunable resonator capacitor coupled to one of the coupling capacitors. At least one resistance is coupled in series between at least one of the coupling capacitors for providing enhanced out of band rejection of the filter. | 08-04-2011 |
20110187449 | Wideband analog lowpass filter - A low pass filter includes an RF input terminal, an RF output terminal, a plurality of inductors coupled in series between the RF input and output terminals, at least one electrically tunable capacitor coupled between ground and a node of one of the inductors. At least one of the inductors includes a winding, and a resistance and a capacitance coupled in series across a portion of the winding to enhance the out of band rejection of the low pass filter. | 08-04-2011 |
20110279175 | SYSTEM AND METHOD FOR RC CALIBRATION USING PHASE AND FREQUENCY - An RC filter is calibrated to a desired cutoff frequency by initializing the filter with a cutoff frequency. An input signal is filtered by the RC filter to provide a filter output signal having phase and frequency values. The cutoff frequency of the RC filter is adjusted based on the phase and frequency values of the filter output signal if the phase and frequency values do not satisfy a predetermined condition. The filtering and adjusting are repeated until the phase and frequency values of the filter output signal satisfy the predetermined condition. A calibration apparatus has a frequency generator, a resistor-capacitor (RC) filter, a phase comparator, a frequency detector, and a state machine. The phase comparator, frequency detector, and state machine are configured to calibrate the RC filter to a cutoff frequency specified by the reference signal based on a filter output signal of the RC filter. | 11-17-2011 |
20110279176 | Combline filter - A microstrip combline bandpass filter includes an input port, an output port, and a plurality of resonators each including a microstrip line having a first end and a second end. One of the plurality of resonators is connected to the input port, and another of the plurality of resonators is connected to the output port. The filter also includes a plurality of pairs of series coupled varactors. The first end of each microstrip line is coupled to one of the pairs of varactors, and the second end of each microstrip line is coupled to ground. | 11-17-2011 |
20120013398 | Adaptive Spectral Enhancement and Harmonic Separation - A circuit and method perform adaptive spectral enhancement at a frequency ω | 01-19-2012 |
20120075011 | Tunable Biquad Filter Circuit Including Phase Shift Detection and Methods for Using Such - Various embodiments of the present invention provide tunable filter circuits and methods for using such. As an example, a tunable biquad filter is disclosed that includes a tunable biquad circuit, a mixer circuit and a low pass filter. The tunable biquad circuit exhibits a cutoff frequency corresponding to an adjustment value, and is operable to receive an filter input and to provide a filter output. The mixer circuit is operable to provide a product of the filter input and the filter output. The product includes a time dependent component and a static component. The low pass filter is operable to receive the product and to provide the static component. | 03-29-2012 |
20120075012 | Systems and Methods for Filter Initialization and Tuning - Various embodiments of the present invention provide systems and methods for data filter tuning. As an example, a method for filter tuning is disclosed that includes: providing a tunable filter having an operation filter and a calibration filter; applying a low frequency test input to the operation filter in place of an input signal to yield a first filter output; calculating a low frequency magnitude value corresponding to the first filter output; applying a high frequency test input to the operation filter in place of an input signal to yield a second filter output; calculating a high frequency magnitude value corresponding to the second filter output; modifying a tuning factor of the calibration filter when a ratio of the high frequency magnitude value and the low frequency magnitude value is outside of a defined range; and storing the tuning factor of the calibration filter when the ratio of the high frequency magnitude value and the low frequency magnitude value is within the defined range. | 03-29-2012 |
20120098592 | FILTER AUTO-CALIBRATION USING MULTI-CLOCK GENERATOR - A filter auto-calibration system includes a multi-clock module. The multi-clock module includes a multi-clock generator that is configured to generate a clock signal with a variable frequency based on a channel setting. There is at least one filter to be calibrated. An auto-calibration control module is configured to control calibration of the at least one filter based on the channel setting. The multi-clock module is configured to supply the variable frequency clock signal to the at least one filter and to the auto-calibration control module, and the at least one filter is coupled to the auto-calibration control module. | 04-26-2012 |
20120105143 | PROGRAMMABLE ANALOG FILTER - A programmable analog filter includes a crossbar array with a number of junction elements and a filter circuit being implemented within the crossbar array. At least a portion of the junction elements form reprogrammable components within the filter circuit. A method for using a programmable analog filter is also provided. | 05-03-2012 |
20120126882 | METHOD FOR SUPPRESSING INTERFERENCE - In a method for suppressing interference in a controlled variable in a control circuit, in which the actuating variable is the useful signal, the controlled variable is detected continuously, at two successive sampling instants in each case, the values of the controlled variable are subtracted, and if the absolute amount of the difference deviates by a predefinable setpoint value, at least one control parameter is modified, in such a way that the response of the actuating variable to the interference is minimized. | 05-24-2012 |
20120133426 | PHASE-LOCKED LOOP BASED CONTROLLER FOR ADJUSTING AN ADAPTIVE CONTINUOUS-TIME FILTER - A direct conversion radio-frequency (RF) receiver includes a controller and an adaptive continuous-time filter. The adaptive continuous-time filter receives a multiple-bit control signal generated by the controller to adjust a characteristic of the continuous-time filter. The controller generates the multiple-bit control signal in response to process variation in the semi-conductor material used to implement the controller and the adaptive continuous-time filter. A method for tuning an adaptive continuous-time filter comprises determining a RC time constant, converting the RC time constant to a digital word, comparing a select bit of the digital word to a respective bit of a predetermined reference word to generate a control bit, applying the control bit to an adjustable element to modify the RC time constant, repeating the determining, converting, comparing and applying steps until the control bits generate an output word and providing the output word to the adaptive continuous-time filter. | 05-31-2012 |
20120139626 | Analog filter with adjustable filter frequency - A low noise analog filter with adjustable filter frequency includes an oscillatory circuit, whose resonance frequency equals the filter frequency of the filter. The oscillatory circuit has a first circuit branch. One of the frequency determining elements is a capacitance and the other an inductance. The low noise analog filter further includes an amplifier with adjustable amplification installed in one of the two circuit branches. The output of the amplifier is connected with its inverting input via the frequency determining element arranged in such circuit branch. In filter operation, the amplifier amplifies, according to the adjusted amplification, a voltage applied across the frequency determining element arranged in such circuit branch and thereby effects a corresponding change of an electrical current flowing through such frequency determining element. | 06-07-2012 |
20120293248 | ACTIVE AND CONFIGURABLE FILTER DEVICE - An active and configurable filter device includes a first filter with a first quality factor, a second filter with a second quality factor and a third filter with a third quality factor. The first filter defines a bandwidth and central frequency of the filter device. The second filter is connected to the first filter for using the spectrums of the first filter and second filter to define a lower bound frequency and sharpness of the bandwidth of the filter device. The third filter is connected to the second filter for using the spectrums of the first filter and third filter to define an upper bound frequency and sharpness of the bandwidth of the filter device. The first quality factor is an adjustable value in a range of 5 to 15, and the second and the third quality factors are each an adjustable value greater than 15. | 11-22-2012 |
20130009699 | FREQUENCY-VARIABLE FILTER - A frequency-variable filter has a GmC filter having a plurality of OTAs and a capacitor; and a pseudo-random value generator outputting pseudo-random value of which average value in a predetermined time corresponds to an input setting value. And at least an OTA for determining a cut-off frequency, out of the plurality of OTAs, is controlled so that transconductance thereof is variably-controlled according to the pseudo-random values, and the cut-off frequency is variably-controlled based on the input setting value. | 01-10-2013 |
20130021092 | ULTRA LOW CUT-OFF FREQUENCY FILTER - An ultra low cut-off frequency filter. A filter circuit includes a control circuit responsive to an input signal and a feedback signal to generate a control signal. The filter circuit includes a controllable resistor coupled to the control circuit. The controllable resistor is responsive to a reference signal and the control signal to generate the feedback signal. The filter circuit includes a feedback path coupled to the control circuit and the controllable resistor to couple the feedback signal from the controllable resistor to the control circuit, thereby removing noise from at least one of the input signal and the reference signal, and preventing voltage error in the filter circuit. | 01-24-2013 |
20130033307 | High Accuracy RC Calibradion Circuit - In an RC calibration circuit, a single reference current is used to generate voltages across both a resistive and capacitive element. The component value of one of the resistive and capacitive element is successively altered until the voltages are substantially equal. Additionally, parasitic capacitances in the circuit are precharged to the resistive element voltage prior to the comparison. The RC calibration circuit eliminates the errors due to current matching and parasitic capacitances in prior art calibration circuits. The circuit includes a comparator and a digital control circuit (DCW) including a successive approximation register (SAR) holding the value of the digital control word used to control the component value of the tunable resistive or capacitive element. The SAR alters the DCW in an iterative, bit-by-bit binary searching pattern in response to the comparator output. | 02-07-2013 |
20130049849 | FILTER SYSTEM CAPABLE OF AUTOMATICALLY ADJUSTING BANDWIDTH AND METHOD OF AUTOMATICALLY ADJUSTING BANDWIDTH OF A FILTER - A filter system capable of automatically adjusting bandwidth includes a filter and an adaptive unit. The filter is used for filtering a digital signal to generate an output signal to an application unit. The adaptive unit is used for generating an adjustment signal to the filter according to the digital signal and the output signal. The filter dynamically adjusts bandwidth of the filter according to the adjustment signal. | 02-28-2013 |
20130099855 | Filter Shaping Using a Signal Cancellation Function - A signal filter and accompanying methods. In one embodiment, the filter includes a first mechanism for receiving a first signal. A second mechanism employs one or more modified representations of the first signal to cancel one or more frequency components of the first signal, yielding an output signal in response thereto. In a more specific embodiment, the first mechanism includes a splitter for receiving the first signal and splitting the first signal onto a first path and a second path. The second mechanism further includes one or more delay modules and one or more phase shifters in the first path and/or the second path. One or more controllable amplifiers are optionally included in the first path and/or the second path. The one or more delay modules, phase shifters, or amplifiers are responsive to one or more control signals from a controller. The controller is adapted to modify behavior of the second mechanism so that the filter is characterized by a desired frequency response. | 04-25-2013 |
20130278329 | ANALOG LOOP FILTER SYSTEMS, APPARATUS, AND METHODS - Described herein is a distributed analog loop filter that can be employed in a phase locked loop or a delay locked loop. A circuit block of the distributed analog loop filter includes at least two parallel equivalent circuit elements. The parallel equivalent circuit elements each have an input line. The input lines for each of the parallel equivalent circuit elements are activated sequentially, one after the other. The parallel equivalent circuit elements have sequentially produced outputs that are also activated sequentially, one after another. The parallel equivalent circuit elements extend the tuning range of distributed analog filter while reducing noise associated with the distributed analog filter. | 10-24-2013 |
20140015602 | RECONFIGURABLE HIGH-ORDER INTEGRATED CIRCUIT FILTERS - Voltage and current mode reconfigurable n | 01-16-2014 |
20140176232 | CARTESIAN FEEDBACK LOOP TRANSMITTER WITH IMPROVED LOOP FILTER - A filter may include multiple circuit sub-systems, where one circuit sub-system may have an output connected to an input of another circuit sub-system. Each circuit sub-system may include an amplifier with an output connected to the output of the circuit sub-system. Each circuit sub-system may include a first network connecting an input of the circuit sub-system to a first reference input of the amplifier, and a second network connecting the output of the amplifier to the first reference input of the amplifier. The filter may include a link network connecting the output of one circuit sub-system to an input of another circuit sub-system. | 06-26-2014 |
20140210546 | TUNING CIRCUITRY AND METHOD FOR ACTIVE FILTERS - Embodiments of the present invention may include a filter with programmable components, a tuning signal generator, a comparator, and a feedback system. The tuning signal generator may input first and second test signals into the filter and the comparator may sample the output of the filter in response to each respective signal. The comparator may then compare the sampled outputs to predetermined values. In response to the comparator's output, the feedback system may vary the programmable components of the filter until the search of the programmable components is exhausted, yielding first and second tuning results. Finally, the feedback system may determine a final tuning result based on the first and second tuning results. Consequently, the filter's actual corner frequency may be within an acceptable range of a desired corner frequency. | 07-31-2014 |
20140292400 | FILTER AUTO-CALIBRATION USING MULTI-CLOCK GENERATOR - A filter auto-calibration system comprises a multi-clock module that includes a multi-clock generator configured to generate a first variable frequency signal based on a channel setting, the multi-clock generator comprising a quadrature signal generator configured to generate an in-phase component and a quadrature component of the first variable frequency signal; and a mixer configured to generate an in-phase component and a quadrature component of a quadrature signal from a received signal other than the first variable frequency signal. The system also comprises at least one filter to be calibrated, and an auto-calibration control module coupled to the multi-clock module and the at least one filter, the auto-calibration control module configured to receive the in-phase component and quadrature component of the first variable frequency signal from the multi-clock module, and configured to control calibration of the at least one filter based on the channel setting. | 10-02-2014 |
20140312965 | VARIABLE ADMITTANCE CIRCUIT - A programmable variable admittance circuit may be used in a programmable filter or a variable gain amplifier in a number of different applications including tuners and other RF receiver circuits. A variable admittance circuit and operation is described including a number of switchable admittance elements arranged in parallel branches. The variable admittance circuit requires fewer transitions to change between successive admittance values than a binary weighted circuit and fewer branches for implementation then a thermometry admittance circuit. | 10-23-2014 |
20140333373 | SHARP PROGRAMMABLE FILTERS USING PERIODICALLY TIME-VARYING COMPONENTS - A method and apparatus for selective programmable filtering using analog circuits with time-varying components (e.g., resistances, capacitances) is presented. An analog front end receives an electronic signal and filters said signal by a passive or active continuous-time filter, having a combination of equivalent memory-less (e.g., resistive) and memory (e.g., capacitive or inductive) elements. A variable resistor circuit allows switching through a range of values to control one or more of the equivalent resistances of the passive or active continuous-time filter. The variable resistors are controlled using a control circuit to periodically modulate the resistances in the continuous-time filter between periodic sampling instances, such as during analog to digital conversion. Such periodic modulation of the resistances in the continuous-time filter allows for the programming and enhancement of the selectivity of said filter. | 11-13-2014 |
20150022261 | DISTRIBUTED LOAD CURRENT SENSING SYSTEM - A distributed load current sensing system being connected to a power input terminal that is connected to a main power trunk that has one or multiple load branches connected thereto is disclosed to include a power bus connected to the main power trunk, an active power filter connected to the power bus and a load current sensor device coupled with each load branch for sensing the load current of each load branch and providing the sensed signal to the active power filter so that the active power filter can generate a compensation signal accurately. | 01-22-2015 |
20150061758 | SIGNAL PROCESSING DEVICE AND SIGNAL PROCESSING METHOD - Embodiments of the invention disclose a signal processing device and a signal processing method and a device and a method for signal processing. The signal processing device includes a sampling module, a first segmentation module, a second segmentation module, and a detection module. The sampling module samples an input signal to generate a sample signal. The first segmentation module calculates a first segment value according to the sample signal during a first time interval. The second segmentation module calculates a second segment value according to the sample signal during a second time interval different in length from the first time interval. The detection module generates a detection signal according to the determination of whether the first segment value lies out of a first range, and whether the second segment value lies out of a second range. | 03-05-2015 |
20150326202 | ELECTRONICALLY TUNABLE FILTER - An electronically tunable filter (ETF) and systems comprising an ETF are disclosed herein. The ETF comprises: a first image rejection mixer; a second image rejection mixer; a first hybrid coupler, the first hybrid coupler being coupled to the first image rejection mixer; a second hybrid coupler, the second hybrid coupler being coupled to the second image rejection mixer; an internal filter coupled to the first hybrid coupler and the second hybrid coupler; a control port for receiving a control signal; a power splitter coupled to the control port, the first image rejection mixer, and the second image rejection mixer; a first port coupled to the first image rejection mixer; and a second port coupled to the first image rejection mixer. | 11-12-2015 |
20160087601 | FULLY ELECTRONICALLY PROGRAMMABLE COMPLEX FILTER - The fully electronically programmable complex filter employs a network of current amplifiers (CAs), each CA having differential pairs biased with different tail currents, the outputs being programmed by adjusting these tail currents. Each CA has an RC circuit at its input including a resistor R and a capacitor C, and a feedback path connecting one of its outputs to the RC circuit, thereby offering independent programmability of center frequency, pole frequency, and programmable gain. Optimal gain parameters set the electronically programmable pole frequency, gain and center frequency to accommodate Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) and Terrestrial Digital Multimedia Broadcasting (T-DMB). | 03-24-2016 |
20160380618 | FEEDFORWARD FILTER USING TRANSLATIONAL FILTER - Described in embodiments herein are techniques for realizing filters having a variety of frequency responses, such as multiple pass-bands, high out-of-band rejection, without complicated designs. In accordance with an embodiment, a feedforward filter includes a first path, at least one second path and a signal combiner. The first path has a first translational filter, and employed for providing a first frequency response and generating a first output in response to an input signal based on the first frequency response. The at least one second path has a second translational filter and is coupled to the first path. The at least one second path is employed for providing a second frequency response that is different from the first frequency response to the input signal, and generating at least one second output in response to the input signal based on the second frequency response. The signal combiner is coupled to the first path and the second path, and employed for combining the first output and the at least one second output to generate a filtered signal. | 12-29-2016 |