3990 results about "Bandpass filtering" patented technology

Apparatus, method, logic arrangement and storage medium are provided for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source can be split into N spectral bands. The N spectral bands can be individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band may be detected by a separate photo detector and amplified. For each spectral band, the signal can be band p3 filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is likely reduced by a factor equal to the number of spectral bands, while the signal amplitude can remain the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.

The invention provides a transceiver for Zigbee and Bluetooth communications integrating a Zigbee transceiver and a Bluetooth transceiver. The transceiver includes an RF processor 110, a variable bandpass filter 120, an FSK modulator / demodulator 130, a memory 140, a baseband processor 150, a main controller 160, and a channel selection / frequency hopping controller 170. The invention integrates the Zigbee transceiver and the Bluetooth transceiver so as to partially make common use of a higher layer application and a physical layer of the Zigbee transceiver and the Bluetooth transceiver. As a result, the invention has the advantage of functioning as a transceiver for Zigbee and Bluetooth communications, without causing a significant increase in size and unit price.

A waveform adaptive transmitter that conditions and / or modulates the phase, frequency, bandwidth, amplitude and / or attenuation of ultra-wideband (UWB) pulses. The transmitter confines or band-limits UWB signals within spectral limits for use in communication, positioning, and / or radar applications. One embodiment comprises a low-level UWB source (e.g., an impulse generator or time-gated oscillator (fixed or voltage-controlled)), a waveform adapter (e.g., digital or analog filter, pulse shaper, and / or voltage variable attenuator), a power amplifier, and an antenna to radiate a band-limited and / or modulated UWB or wideband signals. In a special case where the oscillator has zero frequency and outputs a DC bias, a low-level impulse generator impulse-excites a bandpass filter to produce an UWB signal having an adjustable center frequency and desired bandwidth based on a characteristic of the filter. In another embodiment, a low-level impulse signal is approximated by a time-gated continuous-wave oscillator to produce an extremely wide bandwidth pulse with deterministic center frequency and bandwidth characteristics. The UWB signal may be modulated to carry multi-megabit per second digital data, or may be used in object detection or for ranging applications. Activation of the power amplifier may be time-gated in cadence with the UWB source thereby to reduce inter-pulse power consumption. The UWB transmitter is capable of extremely high pulse repetition frequencies (PRFs) and data rates in the hundreds of megabits per second or more, frequency agility on a pulse-to-pulse basis allowing frequency hopping if desired, and extensibility from below HF to millimeter wave frequencies.

A data-modulated ultra wideband transmitter that modulates the phase, frequency, bandwidth, amplitude and / or attenuation of ultra-wideband (UWB) pulses. The transmitter confines or band-limits UWB signals within spectral limits for use in communication, positioning, and / or radar applications. One embodiment comprises a low-level UWB source (e.g., an impulse generator or time-gated oscillator (fixed or voltage-controlled)), a waveform adapter (e.g., digital or analog filter, pulse shaper, and / or voltage variable attenuator), a power amplifier, and an antenna to radiate a band-limited and / or modulated UWB or wideband signals. In a special case where the oscillator has zero frequency and outputs a DC bias, a low-level impulse generator impulse-excites a bandpass filter to produce an UWB signal having an adjustable center frequency and desired bandwidth based on a characteristic of the filter. In another embodiment, a low-level impulse signal is approximated by a time-gated continuous-wave oscillator to produce an extremely wide bandwidth pulse with deterministic center frequency and bandwidth characteristics. The UWB signal may be modulated to carry multi-megabit per second digital data, or may be used in object detection or for ranging applications. Activation of the power amplifier may be time-gated in cadence with the UWB source thereby to reduce inter-pulse power consumption. The UWB transmitter is capable of extremely high pulse repetition frequencies (PRFs) and data rates in the hundreds of megabits per second or more, frequency agility on a pulse-to-pulse basis allowing frequency hopping if desired, and extensibility from below HF to millimeter wave frequencies.

A telemetry receiver for an implantable medical device (IMD) such as a cardiac pacemaker has an RF antenna coupled to a telemetry circuit that includes an out-of-band rejection filter comprising a thin film bulk acoustic resonator filter. The telemetry circuit includes an amplifier coupled to the thin film bulk acoustic resonator filter and a demodulator coupled to the amplifier. The filter, amplifier and demodulator are all fabricated on a common integrated circuit die. A multichannel telemetry receiver for an IMD has a plurality of thin film bulk acoustic resonator bandpass filters defining individual channels. Identification of a preferred data transmission channel for communication of programming data to the IMD is determined by obtaining samples of the signals being passed by each of a plurality of thin film bulk acoustic resonator bandpass filters that define individual channels and evaluating the samples to determine the noise level for each channel.

A filter network having the capability of establishing multiple, tunable notch frequencies. A notch filter path is established for each notch frequency and includes a bandpass filter and inverter. An input RF signal covering a wide frequency range is applied to all the notch filter paths. Each notch filter path produces an output spectrum that is equal in magnitude and 180.degree. out of phase with respect to an undesired frequency spectrum. A combiner circuit combines the outputs of each notch filter path in parallel with the RF input signal to produce an RF output signal with all desired spectra unchanged and all undesired spectra attenuated.

A phased-array antenna filter and diplexer for a super economical broadcast system are provided. The filter and diplexer includes a signal divider tee diplexer, a receive filter and a transmit filter. The diplexer includes a tee branch point, an antenna port, a transmit port and a receive port. The receive filter includes a flat, multi-pole bandpass filter, an input port and an output port, where the input port is coupled to the diplexer receive port to define a receive signal path, from the tee branch point to the receive input port, that has a length of approximately one quarter receive wavelength. The transmit filter includes a folded, multi-pole bandpass filter, an input port and an output port, where the output port is coupled to the diplexer transmit port to define a transmit signal path, from the tee branch point to the transmit output port, that has a length of approximately one quarter transmit wavelength.

A device for bi-directional amplification of data signals over power lines is disclosed. In one embodiment, the device includes a bandpass filter, a frequency converter and an amplifier. The bandpass filter filters out undesired frequencies and the frequency converter converts the frequency band of the data signals to a different frequency band. The output of the filter is provided to the amplifier for amplifying the frequency converted data signals for transmission over power line.

A spectroscopic apparatus which is compact in size and performs high-precision light-splitting with a large angular dispersion. An optical input-processing section outputs a filtered transmitted light, using a bandpass filter that transmits only wavelength bands at one period of an input light, and collects the filtered transmitted light to generate a collected beam. An optic includes a first reflection surface and a second reflection surface which are high but asymmetric in reflectivity, and causes the collected beam incident thereon to undergo multiple reflections within an inner region between the first reflection surface and the second reflection surface, to thereby cause split beams to be emitted via the second reflection surface. A received light-processing section performs received light processing of the beams emitted from the optic. A control section variably controls at least one of a filter characteristic of the bandpass filter and an optical length through the optic.

A hearing compensation system for the hearing impaired comprises an input transducer for converting acoustical information at an input to electrical signals at an output, an output transducer for converting electrical signals at an input to acoustical information at an output, a plurality of bandpass filters, each bandpass filter having an input connected to the output of said input transducer, a plurality of AGC circuits, each individual AGC circuit associated with a different one of the bandpass filters and having an input connected to the output of its associated bandpass filter and an output connected to the input of the output transducer. The bandpass filters and AGC circuits may be divided into two processing channels, one for low frequencies and one for high frequencies and may drive separate audio transducers, one configured for maximum efficiency at low frequencies and one configured for maximum efficiency at high frequencies.

A component that functions with bulk acoustic waves, particularly a bandpass filter, has an increased number of degrees of design freedom in order to improve the transmission characteristics of the component. The component has BAW resonators coupled acoustically in the vertical and / or lateral direction through common electrodes, coupling layer systems and through the excitation of lateral acoustic modes. Through the acoustic coupling of the resonators, it is possible to create additional pole points in the transfer function so that in this manner, the rejection band characteristics of a bandpass filter can be improved. Through acoustic paths which are added in addition to the electrical connection, the insertion loss can be reduced. Through an acoustic coupling instead of an electrical connection, decoupling between input and output loops of a circuit can be achieved.

A hearing compensation system comprises a plurality of bandpass filters having an input connected to an input transducer and each bandpass filter having an output connected to the input of one of a plurality of multiplicative automatic gain control (MAGC) circuits whose outputs are summed together and connected to the input of an output transducer. The MAGC circuits attenuate acoustic signals having a constant background level without the loss of speech intelligibility. The identification of the background noise portion of the acoustic signal is made by the constancy of the envelope of the input signal in each of the several frequency bands. The background noise that will be suppressed includes multi-talker speech babble, fan noise, feedback whistle, florescent light hum, and white noise. For use in the consumer electronics field background acoustic noise may be sensed and used to adjust gain in the various MAGC circuits so as to improve a user's listening experience, whether the user is hearing impaired or not.

In a multilayer bandpass filter, capacitances are produced between a ground electrode provided in a ground electrode formation layer and capacitor electrodes provided in a capacitor electrode formation layer. A plurality of inductor electrodes are defined by via-electrodes and line electrodes such that loop planes of inductor electrodes at least partially overlap each other when seen in a direction in which the inductor electrodes are arranged. The direction of the loop of the inductor electrode of the LC parallel resonator located (at a first stage) at an input end is set to be opposite to the direction of the loop of the inductor electrodes of the LC parallel resonator (at a second stage) adjacent to the inductor electrode of the LC parallel resonator located at the input end. Similarly, the direction of the loop of the inductor electrode of the LC parallel resonator located (at a fifth stage) at an output end is set to be opposite to the direction of the loop of the inductor electrodes of the LC parallel resonator (at a fourth stage) adjacent to the inductor electrode of the LC parallel resonator located at the output end.

A method of visually detecting a leak of a chemical emanating from a component. The method includes: aiming a passive infrared camera system towards the component; filtering an infrared image with an optical bandpass filter, the infrared image being that of the leak; after the infrared image passes through the lens and optical bandpass filter, receiving the filtered infrared image with an infrared sensor device; electronically processing the filtered infrared image received by the infrared sensor device to provide a visible image representing the filtered infrared image; and visually identifying the leak based on the visible image. The passive infrared camera system includes: a lens; a refrigerated portion including therein the infrared sensor device and the optical bandpass filter (located along an optical path between the lens and the infrared sensor device). At least part of a pass band for the optical bandpass filter is within an absorption band for the chemical.

A spectroscopic apparatus which is compact in size and performs high-precision light-splitting with a large angular dispersion. An optical input-processing section outputs a filtered transmitted light, using a bandpass filter that transmits only wavelength bands at one period of an input light, and collects the filtered transmitted light to generate a collected beam. An optic includes a first reflection surface and a second reflection surface which are high but asymmetric in reflectivity, and causes the collected beam incident thereon to undergo multiple reflections within an inner region between the first reflection surface and the second reflection surface, to thereby cause split beams to be emitted via the second reflection surface. A received light-processing section performs received light processing of the beams emitted from the optic. A control section variably controls at least one of a filter characteristic of the bandpass filter and an optical length through the optic.

A waveguide bandpass filter for use in microwave and millimeter-wave satellite communications equipment is presented. The filter is based on a substrate integrated waveguide (SIW) having several cascaded oversized SIW cavities. The filter is implemented in a printed circuit board (PCB) or a ceramic substrate using arrays of standard metalized via holes to define the perimeters of the SIW cavities. Transmission lines of a microstrip line, a stripline or coplanar waveguide are used as input and output feeds. The transmission lines have coupling slots for improved stopband performance. The filter can be easily integrated with planar circuits for microwave and millimeter wave applications.

Apparatus and method for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source is split into N spectral bands. The N spectral bands are individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band is detected by a separate photo detector and amplified. For each spectral band the signal is band pass filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is reduced by a factor equal to the number of spectral bands. The signal remains the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.

Apparatus and method for increasing the sensitivity in the detection of optical coherence tomography and low coherence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source is split into N spectral bands. The N spectral bands are individually detected and processed to provide an increase in the signal-to-noise ratio by a factor of N. Each spectral band is detected by a separate photo detector and amplified. For each spectral band the signal is band pass filtered around the signal band by analog electronics and digitized, or, alternatively, the signal may be digitized and band pass filtered in software. As a consequence, the shot noise contribution to the signal is reduced by a factor equal to the number of spectral bands. The signal remains the same. The reduction of the shot noise increases the dynamic range and sensitivity of the system.

Controlling a level of electrosurgical energy provided to tissue based on detected arcing patterns or impedance changes. The drag force imposed on an electrode or blade of an electrosurgical instrument may be controlled by adjusting the level of electrosurgical energy based on the arcing patterns or impedance changes. The arcing patterns or impedance changes may be detected by sensing and analyzing voltage and / or current waveforms of the electrosurgical energy The current and / or voltage waveform analysis may involve calculating impedance based on the voltage and current waveforms and calculating changes in impedance over time. The waveform analysis may involve detecting harmonic distortion using FFTs, DFTs, Goertzel filters, polyphase demodulation techniques, and / or bandpass filters. The waveform analysis may involve determining a normalized difference or the average phase difference between the voltage and current waveforms.

In one embodiment, the present invention includes a test signal generator capable of producing an impedance test signal comprising of a sine wave having a known frequency. The test signal generator may include a crystal oscillator, a counter, and a lookup table. The lookup table output is applied to a digital to analog converter and is then low pass filtered using a conventional analog filter to produce a sine wave of a known frequency and voltage amplitude. The test signal flows through the electrode and combines with an electrophysiological signal to form a combined signal. A signal processor is used to isolate the combined signal into the test signal component and the electrophysiological component. The signal processor digitally low pass filters the combined signal and the output of the low pass filter is the electrophysiological signal. The signal processor then digitally bandpass filters the combined signal using a filter with a center frequency which is the same as the test frequency. The output of this filter is then used to calculate the electrode impedance.

A cardiac monitoring and / or stimulation method and systems provide monitoring, defibrillation and / or pacing therapies, including systems detecting and / or treating cardiac arrhythmia. A system includes a housing coupled to a plurality of electrodes configured for subcutaneous non-intrathoracic sensing. A signal processor receives a plurality of composite signals associated with a plurality of sources, separates a signal from the plurality of composite signals using blind source separation, and identifies a cardiac signal. The signal processor may iteratively separate signals from the plurality of composite signals until the cardiac signal is identified. A method of signal separation includes detecting a plurality of composite signals at a plurality of locations, separating a signal using blind source separation, and identifying a cardiac signal. The separation may include a principal component analysis and / or an independent component analysis. The composite signals may be filtered before separation using band-pass filtering, adaptive, or other filters.

Various embodiments of the present invention provide systems and apparatus directed toward using a contact lens and deflection optics to process display information and non-display information. In one embodiment of the invention, a display panel assembly is provided, comprising: a transparent substrate that permits light to pass through substantially undistorted; a two-dimensional display panel disposed on the transparent substrate, wherein the display panel comprises pixel elements sufficiently spaced with respect to each other to allow light to pass through the display panel assembly; and at least one filter disposed on at least one pixel element. The filter may comprise a bandpass filter that reduces bandwidths of emitted light from the pixel element, or a polarizer filter that limits polarity of emitted light from the pixel element.

The present invention is a hybrid RF-digital signal processor-based filter for multiband radio architectures systems capable of spectrum re-farming and software defined radios. It performs low-loss frequency agile multiple notch filtering at RF where a large dynamic range exists at a filter input between signals in a stopband and passband. It is a frequency dependent signal attenuation apparatus having two paths connected together by directional couplers. The first path comprising a component such as a delay component or duplexer. The second path comprising a bandstop filter connected to a down converter, a digital filter, and an up converter. At the output of a power amplifier, the invention can be used to attenuate spurs, or noise within bands with strict emission constraints. At the input of a low noise amplifier, the invention can be used to attenuate blockers and transmitter noise outside of the receiver passband.

The invention concerns a conditioning circuit (10) for an external signal (IN) representative of a physiological quantity, arranged between an optical sensor (11) and a processing unit (12), the received external signal (IN) being broken down into a useful component and an ambient component, characterized in that the conditioning circuit includes a first stage (13) including a transimpedance amplifier with an incorporated high pass filter (15) using a feedback loop to subtract the ambient signal component from the received external signal, and to deliver at output an amplified useful signal (IN1), a second stage (16) including a blocker sampler circuit (17) for demodulating the amplified useful signal and delivering at output a demodulated useful signal (IN2), and a third stage (18) including a bandpass filter (19) for filtering the demodulated useful signal in the frequency band of the physiological quantity to be detected and for transmitting a conditioned signal (OUT) to the processing unit.

A component that functions with bulk acoustic waves, particularly a bandpass filter, has an increased number of degrees of design freedom in order to improve the transmission characteristics of the component. The component has BAW resonators coupled acoustically in the vertical and / or lateral direction through common electrodes, coupling layer systems and through the excitation of lateral acoustic modes. Through the acoustic coupling of the resonators, it is possible to create additional pole points in the transfer function so that in this manner, the rejection band characteristics of a bandpass filter can be improved. Through acoustic paths which are added in addition to the electrical connection, the insertion loss can be reduced. Through an acoustic coupling instead of an electrical connection, decoupling between input and output loops of a circuit can be achieved.

A device for seamlessly providing 10BASE-T compatible data communications over an ordinary single twisted-pair home phone line between multiple computers and / or peripherals is disclosed. Each component that is to communicate over a home phone line needs a 10BASE-T compatible network interface card (NIC) for interfacing with the device. A transmit / receive switch is used to switch the device between a transmit mode and a receive mode. When a signal is being transmitted from a component, a Manchester decoder converts the signals received from the NIC into a raw data stream. A differential converter converts the raw data signal received from the NIC to a differential signal. A modulator is used to modulate the signal to a RF signal using a PSK, QPSK, QAM, MCM or similar modulation schemes. A filter is used to limit the bandwidth of the modulated signal and a driver is used to amplify the signal to match the impedance of the phone line. When the device receives a signal over the phone line, the signal is filtered using a bandpass filter and then amplified. The signal is then demodulated using an appropriate demodulation scheme before being differentially encoded. A Manchester encoder encodes the received signal for compatible operation with a receiving NIC.

A new optical sensing device containing fiber Bragg gratings, a scanning bandpass filter, an interferometer and multiple photodetectors is disclosed. The present invention also describes a new system and method for fibre Bragg grating (FBG) sensor interrogation and multiplexing. The new system combines a scanning Fabry-Perot (SFP) bandpass filter used to wavelength-multiplex multiple gratings in a single fiber, and an unbalanced Mach-Zehnder fibre interferometer made with a 3x3 coupler to detect strain-induced wavelength shifts. A passive technique for interferometer drift compensation using non-sensing FBGs is included in the system. A complete prototype system interrogates four gratings in a single fiber at a Nyquist sampling rate up to 10 kHz, with a noise floor measured near 4 nepsi Hz-½ above 0.1 Hz. The inclusion of the interferometer drift compensation technique is shown to make quasi-static measurements feasible.