289 results about "Filter bandwidth" patented technology

Methods, systems and devices are described for detecting noise in a touchpad or other sensor that produces an output in response to a stimulus that is applied at or near a sensing region. According to various embodiments, a carrier signal is applied to the sensing region at two or more frequencies to thereby produce an output from the sensing region at each frequency. Each of the outputs is demodulated and filtered by a demodulation filter having a demodulation filter bandwidth. The various frequencies applied to the carrier signal are selected such that a difference between the frequencies is less than the demodulation filter bandwidth. At least some of the effects of the stimulus are removed from the outputs produced by the various carrier frequencies to produce two or more filtered outputs. The filtered outputs are then added, combined or otherwise processed to detect noise contained therein. If noise contained in one or more of the filtered outputs reaches an unacceptable level, the carrier signal may be shifted to a new sensing frequency for subsequent operation of the sensor.

A digital IF receiver (DRX) module directly compatible with advanced radar systems such as synthetic aperture radar (SAR) systems. The DRX can combine a 1 G-Sample / sec 8-bit ADC with high-speed digital signal processor, such as high gate-count FPGA technology or ASICs to realize a wideband IF receiver. DSP operations implemented in the DRX can include quadrature demodulation and multi-rate, variable-bandwidth IF filtering. Pulse-to-pulse (Doppler domain) filtering can also be implemented in the form of a presummer (accumulator) and an azimuth prefilter. An out of band noise source can be employed to provide a dither signal to the ADC, and later be removed by digital signal processing. Both the range and Doppler domain filtering operations can be implemented using a unique pane architecture which allows on-the-fly selection of the filter decimation factor, and hence, the filter bandwidth. The DRX module can include a standard VME-64 interface for control, status, and programming. An interface can provide phase history data to the real-time image formation processors. A third front-panel data port (FPDP) interface can send wide bandwidth, raw phase histories to a real-time phase history recorder for ground processing.

The invention discloses an SINS / GPS super-compact integrated navigation system and an implementing method thereof. The method comprises the following steps: the doppler frequency assistance is provided for a GPS carrier loop by using the velocity information of a strapdown inertial navigation system, therefore, the loop equivalent bandwidth is increased, the influence of the carrier dynamic stateon the carrier loop is lowered, and the noise suppression capability is improved by reducing the bandwidth of a filter; meanwhile, in order to eliminate the correlation between the pseudo-range rate error and the inertial navigation error, a carrier loop tracking error model is obtained by establishing the relationship between the carrier tracking error and the inertial navigation speed error, andthe influence of the carrier tracking error is subduced in the measurement equation; and in addition, the carrier frequency is adjusted according to the output error estimation information, and the tracking accuracy of the carrier loop is enhanced. The invention can effectively enhance the noise suppression capability and the dynamic tracking performance of the tracking loop and enhance the tracking accuracy of a GPS receiver and the navigation accuracy of the integrated navigation system under strong interference and high dynamic circumstance.

A system that blends a hybrid radio signal may provide reduced audio content skipping and may determine an audio correlation between analog and digital signal components in the hybrid radio signal before blending from the analog signal component to the digital signal component. The system may reduce volume level transitions during blending by adjustment of blend and cross-fade variables, as well as setting a hysteresis mode to prevent undesirable sequential jumping from digital mode back to analog mode. The system also may compensate for digital AM frequency quality issues by adjustment of a filter bandwidth when the receiver blends an AM signal from analog to digital mode.

A system for blending a hybrid radio signal provides reduced volume level transitions during blending from an analog component of the hybrid signal to the digital component by adjusting blend and cross-fade variables, as well as setting a hysteresis mode to prevent undesirable jumping from digital mode back to analog mode sequentially. The system also compensates for digital AM frequency quality issues by adjusting a filter bandwidth when the transceiver blends the AM signal from analog to digital mode.

A cycle slip detector and detection method for a phase comparison circuit are provided. The cycle slip detector includes a cycle slip detection filter possessing a predetermined filter bandwidth and a predetermined high frequency cut-off. The cycle slip detection filter receives a phase difference generated by the phase comparison circuit and transforms the phase difference into a filtered phase difference. The cycle slip detector further includes a compensator communicating with the cycle slip detection filter. The compensator compensates the magnitude based on a predetermined compensation response. The cycle slip detector further includes a cycle slip occurrence detector communicating with the compensator. The cycle slip occurrence detector compares a compensated magnitude of the filtered phase difference to a predetermined cycle slip threshold and generates a cycle slip output if the compensated magnitude exceeds the predetermined cycle slip threshold.

The invention discloses an integrated optical filter with center wavelength and filter bandwidth both adjustable independently. The optical filter is composed of tunable micro-ring resonators as basic units and comprises an input optical waveguide, a first-level high-order optical filter, an intermediate optical waveguide, a second-level high-order optical filter and an output optical waveguide. The first-level high-order optical filter is used for primary filtering of light guided by the input waveguide; the second-level high-order optical filter is used for secondary filtering of light after the primary filtering. The construction method of the integrated optical filter is that multiple tunable micro-ring resonators are connected in series to form the high-order optical filters with flat-top filter curves; two levels of the high-order optical filters with center wavelength adjustable independently are cascaded to form the integrated optical filter with the center wavelength and filter bandwidth both adjustable independently.

The invention relates to a broadband radio frequency receiver and belongs to the technical field of wireless communication electronics. The broadband radio frequency receiver comprises a radio frequency front end module, an analog base band module and a digital baseband module; a zero-intermediate frequency receiver structure with orthogonal down conversion frequency is adopted; a radio frequency input signal sequentially passes through a low noise amplifier, a passive mixer, a trans-impedance amplifier, a low pass filter, a gain variable amplifier, an analog-digital converter, a decimation filter and a finite impulse response (FIR) filter; multiple radio frequency input signals within 50MHz to 6.3GHz can be processed by switching a low noise amplifier group and configuring local oscillation frequency, a sampling clock, filter bandwidth and the like; an external band-pass filter is not needed, so that the complexity of the system is reduced and the integration level is improved; a working frequency band is widened, and the flexibility and the reliability of the system are improved; in addition, the dynamic range is widened by double loop automatic grain control of a peak detection circuit and a power detection circuit. The broadband radio frequency receiver can be designed into an IP (Internet Protocol) core monolithic integration or can be in an external cascade.

A wireless receiver (10) includes a down converter module (210) operable to deliver a signal having a signal bandwidth that changes over time, a dynamically controllable filter module (200) having a filter bandwidth and fed by said down converter module (210), and a measurement module (295) operable to at least approximately measure the signal bandwidth, said dynamically controllable filter module (200) responsive to said measurement module (295) to dynamically adjust the filter bandwidth to more nearly match the signal bandwidth as it changes over time, whereby output from said filter module (200) is noise-reduced. Other wireless receivers, electronic circuits, and processes for their operation are disclosed.

A novel method and system for clock and data recovery in high speed serial transceiver applications allowing for fast bit lock acquisition and small data tracking error is presented. The clock and data recovery method utilizes a variable bandwidth loop filter to generate a phase adjustment signal used by a phase interpolator in generating a clock signal at the same frequency and phase as the incoming digital data stream. The loop filter bandwidth may be adjusted to correspond with a plurality of clock and data recovery operating modes. In particular, the filter bandwidth may be set to either a high or a low value depending on whether the phase difference between the recovered clock signal and the incoming digital data stream is above or below a programmed threshold value.

RFID readers transmit data to query tags at one or more data rates. Before transmitting data, the RFID readers also transmit special preambles that inform of the data rate that will be used for transmitting the data. The preambles have a call aspect and a rate aspect. The rate aspect has a feature substantially determined from a rate selected for transmitting the data. The feature may encode the rate indirectly or explicitly. The call aspect may be implemented by call transitions that define a timing, whose duration is independent of the selected rate. The duration may be advantageously set according to an assumed state of the RFID tag bandwidth filter. Therefore an RFID tag may use the call aspect of the preamble to prepare itself for receiving data, and the rate aspect to determine its rate of transmission for setting its filter bandwidth accordingly.

LTCC coupled stripline resonator filters for use as bandpass filters are implemented with combline topology or with interdigital topology. The filter bandwidths range from about 0.3 GHz to about 4.5 GHz, or higher, depending of the manufacturing limitations with frequency operation of about 0.1 GHz to about 100 GHz. The filters have a plurality of through plated vias extending through the filters and connecting the top and bottom ground layers to form electric walls thereby reducing the coupling between the adjacent resonators.

A device for spatial positioning systems includes a programmable measurement filter that is dynamically tuned by the device signal processing unit. The signal processing unit analyzes available data including the measurement signal to determine the likelihood that a detected measurement comprises true device movement and adjusts the measurement filter bandwidth accordingly.

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.

An booster / amplifier receives a plurality of RF signals, including a subject RF signal. A location-based signal spectrum is determined by performing either a frequency scan or an information lookup operation. An initial filter bandwidth for the booster / amplifier is set based at least in part on the determined signal spectrum and a target time delay interference. In one embodiment, the initial filter bandwidth is set such that both the TDI and ACI are optimized / minimized. The initial filter bandwidth subsequently may be adjusted from its initial value based on actual measured ACI and / or TDI values.

A microelectromechanical (MEM) filter is disclosed which has a plurality of lattice networks formed on a substrate and electrically connected together in parallel. Each lattice network has a series resonant frequency and a shunt resonant frequency provided by one or more contour-mode resonators in the lattice network. Different types of contour-mode resonators including single input, single output resonators, differential resonators, balun resonators, and ring resonators can be used in MEM filter. The MEM filter can have a center frequency in the range of 10 MHz-10 GHz, with a filter bandwidth of up to about 1% when all of the lattice networks have the same series resonant frequency and the same shunt resonant frequency. The filter bandwidth can be increased up to about 5% by using unique series and shunt resonant frequencies for the lattice networks.

The invention discloses an optical frequency comb multi-section light wave splicing method of a linear frequency sweeping light source with an ultra-wide spectrum range. The optical frequency comb multi-section light wave splicing method comprises the following steps: step 1, realizing multi-wavelength linear frequency sweeping through utilizing linear changes of light frequency along with time of multi-wavelength optical frequency comb light wave output from a single-sideband light modulator, so as to generate continuous light containing a multi-wavelength simultaneous linear frequency sweeping signal; step 2, adjusting a filter bandwidth of a continuous light signal through an electric control tunable filter, so as to enable a central frequency change speed to be the same as a frequency sweeping speed of frequency sweeping light wave; linearly changing the speed of a linear frequency sweeping speed gamma along with time until the central frequency reaches v1+(N-1)delta f and a central frequency initial value is equal to minimum frequency sweeping light frequency, so as to obtain linear frequency sweeping light wave with the ultra-wide spectrum range. Compared with the prior art, influences of laser relaxation vibration can be basically avoided, and the linear frequency sweeping speed with the extra-high speed can be realized; the frequency sweeping light source with high frequency sweeping linearity and high frequency precision is guaranteed.

A timing recovery scheme demarcates a complete range of inter-symbol interference free (ISI-free) sampling positions available in a cyclically extended symbol. The timing recovery scheme computes an ensemble correlation between the cyclic extension and the data part of symbols to estimate timing. The ensemble correlation function retains delay-spread and timing information by separately maintaining the correlation value for each sample position within the symbol duration and combines the correlation values for identical sample positions over an ensemble of symbols. In this manner, the scheme not only provides timing estimates, but can also provide estimates of the multipath delay-spread in a channel. The delay-spread estimates provide valuable information about the nature of the channel. A receiver can use this information, for example, to adjust the frequency-domain channel interpolation filter bandwidth in order to improve performance for the given channel condition.

The invention discloses an active RC (Resistance-Capacitance) filter bandwidth calibration method. An RC filter and a measurement module are provided in the method, wherein the output of the filter is a square wave signal with a fixed frequency, and the measurement on an RC constant is converted into the measurement on a reference value; the measurement module is used for converting the measurement on the RC value into a reference value of a clock counting of which the frequency is disclosed in the specification in a pulse width; a mode of increasing capacitor arrays is adopted, and a counting value N is proximal through regulating the capacitor arrays; and an offset factor alpha is calculated, and through changing the capacitance arrays, the current RC constant is multiplied by a coefficient 1 / alpha to calibrate the corner frequency of the filter to a design value. In the invention, the RC constant is measured and calibrated by adopting the circuit structure through frequency measurement, so that the active RC filter bandwidth can be calibrated. The method can be better applied to the automatic calibration of the filter bandwidth of the active RC filter.

The invention discloses an electromagnetic two-dimensional reconfigurable filter with an adjustable frequency bandwidth and belongs to the technical field of microwave and millimeter waves. Accordingto the reconfigurable filter, adjustable capacitors are loaded in a substrate integrated waveguide resonator to adjust the operating frequency of each cavity, the ferrite materials are loaded at thecoupling window of the substrate integrated waveguide filter to directly control the coupling strength between the substrate integrated waveguide resonators, the adjustable capacitance is loaded on the input-output feeder to adjust the external quality factor, then the frequency of the reconfigurable filter is adjusted and the bandwidth of the filter are flexibly controlled. Compared with the traditional single electrical reconfigurable substrate integrated waveguide filters, the filter realizes a flexible design of bandwidth, the waveform retention degree of the filter is greatly improved andthe future multi-band, miniaturization, intelligent wireless communication equipment and systems can be broadly applied in potential.

A slot-line dual-band bandpass filter comprises a microwave medium dielectric slab substrate, upper microstrip transmission lines and lower slot-line resonators. A third spiral slot-line stub and a first spiral slot-line stub are loaded to a first open ring slot-line resonator to form an open ring slot-line resonator with the loaded spiral slot-line stub. A fourth spiral slot-line stub and a third spiral slot-line stub are loaded to a second open ring slot-line resonator to form an open ring slot-line resonator with the loaded spiral slot-line stub. The two open ring slot-line resonators with the loaded spiral slot-line stub are coupled to input and output feeders by means of clearance coupling and vertical coupling. The slot-line dual-band bandpass filter allows for independent control of central frequency of two bands and circuit miniaturization; power carrying capacity of the microwave filter is improved; microwave filter bandwidth control is realized; stop-band characteristic of the filter is improved effectively; the slot-line dual-band bandpass filter is compact in design and easy to integrate.

A channel equalizer obtains channel impulse responses (CIRs) for all subcarriers by way of filtering channel impulse responses of specific subcarriers using at least two filters. One of the two filters may be a low pass filter. At least one other of the at least two filters is implemented as a band pass filter having a variable filtering bandwidth, being available to establish various filtering bandwidths in response to various multi-path channel environments. By improving the performance of channel estimation, equalization may be improved.

An optical multiplexer / demultiplexer is described. In this optical multiplexer / demultiplexer, multiple coupled-waveguide grating devices are optically coupled to a bus optical waveguide. A given coupled-waveguide grating device has a band-pass filter characteristic that encompasses multiple optical channels, thereby providing coarse optical filtering. Moreover, the optical multiplexer / demultiplexer includes multiple add / drop filters (such as ring resonators) that optically couple to the coupled-waveguide grating devices. A given add / drop filter has a filter bandwidth corresponding to a given optical channel, thereby providing fine optical filtering. Furthermore, the band-pass filter characteristic of the given coupled-waveguide grating device is approximately equal to or less than a free spectral range (FSR) of the given add / drop filter.

The invention discloses a terahertz wave adjustable narrow band filter based on a silicon-based photonic crystal structure. The filter comprises a filter metal shell, uniform high-resistance silicon wafers, annular gaskets, a spring piece, a driving motor, a lead, a motor driving controller, a translation table and a hollow push post, wherein one end of the filter metal shell is provided with a vertical edgefold inwardly; a plurality of groups of uniform high-resistance silicon wafers and annular gaskets are uniformly arranged at intervals in the filter metal shell, then the spring piece is arranged in the filter metal shell, and the same quantity of groups of uniform high-resistance silicon wafers and annular gaskets are arranged at intervals in the filter metal shell again; the hollow push post is sleeved in the other end of the filter metal shell; the outer end of the hollow push post is fixed on the translation table; a translation table base is fixed with the metal shell; the translation table is driven to shift by using the driving motor; and the motor driving controller is used for controlling the driving motor through the lead. The terahertz wave adjustable narrow band filter has the advantages of simple structure, low cost, extremely narrow filtering bandwidth, small loss, wide frequency adjustable range, high modulating speed and high performance.

Aspects of a method and system for signal phase variation detection in communication systems are presented. Aspects of the system may enable detection of phase change between a current received symbol, and one or more previous received symbols. Based on the phase change a channel estimation filter bandwidth may be selected for despreading and / or descrambling one or more subsequent received symbols. In addition, a decision may be made as to whether the subsequent received symbols are to be received based on a closed loop system, or based on an open loop system.

A method and apparatus is disclosed to dynamically select among two or more receiver filter bandwidths to more closely approximate a bandwidth of a corresponding signal field included in a received communications signal. A communications transmitter may transmit a transmitted communication signal in at least one formatted blocks of data or packets. Each one of the at least one formatted blocks of data or packets include at least one single stream signal field such as, but not limited to, a single stream preamble, a single stream signal field, and / or a single stream single stream information payload in accordance with the known single stream communications standard and / or at least one multiple stream signal field such as, but not limited to, a multiple stream preamble, a multiple stream signal field, and / or a multiple stream multiple stream information payload in accordance with the known multiple stream communications standard. The communications receiver may include one or more receiver filters to select among one or more receiver filter bandwidths to filter the at least one single stream signal field and / or the at least one multiple stream signal field.

RFID readers transmit data to query tags at one or more data rates. Before transmitting data, the RFID readers also transmit special preambles that inform of the data rate that will be used for transmitting the data. The preambles have a call aspect and a rate aspect. The rate aspect has a feature substantially determined from a rate selected for transmitting the data. The feature may encode the rate indirectly or explicitly. The call aspect may be implemented by call transitions that define a timing, whose duration is independent of the selected rate. The duration may be advantageously set according to an assumed state of the RFID tag bandwidth filter. Therefore an RFID tag may use the call aspect of the preamble to prepare itself for receiving data, and the rate aspect to determine its rate of transmission for setting its filter bandwidth accordingly.