3259 results about "High-pass filter" patented technology

A multi-band antenna switch circuit including a diplexer connected to an antenna terminal for demultiplexing signals of different passing bands, a first and a second switch circuit for switching a high frequency signal and a low frequency signal demultiplexed by the diplexer to a plurality of transmission/reception terminals, a first and a second low pass filter connected to a transmission path between the diplexer and the transmission terminal or between the first and the second switch circuit and the transmission terminal, and a notch filter provided between the diplexer and the first switch circuit or between the diplexer and the second switch circuit. The multi-band antenna switch circuit includes a high pass filter having an input terminal and an output terminal and provided at least between die diplexer and the antenna terminal and including a first inductor connected between the input terminal and the ground, a first capacitor connected between the input terminal and the output terminal, a second inductor connected to the output terminal, and a second capacitor connected between the second inductor and the ground.

A method and apparatus for sensing and measuring stress waves. The method comprises the steps of: a.) sensing motion, where the motion comprises a stress wave component and a vibration component; b.) separating the stress wave component from the vibration component with a high pass filter to create a signal proportional to the stress wave; c.) amplifying the signal to create an amplified signal; d.) processing the amplified signal with a sample and hold peak detector over a predetermined interval of time to determine peaks of the amplified signal over said predetermined period of time; e.) creating an output signal proportional to the determined peaks of the amplified signal; and, f.) repeating steps d.) and e.). The invention also includes an apparatus for implementing the method of the invention.

A noise reduction circuit for reducing the effects of low frequency noise such as wind noise in communications applications is described. In one embodiment, the noise reduction circuit features a high pass filter formed by exploiting the existing off-chip AC coupling capacitances in making the connection to the source of audio signals. The filter may be adaptive to environmental low frequency noise level through programming the shunt resistances. A low-noise wide dynamic range programmable gain amplifier is also described. Adaptive equalization of the audio signal is also described through the utilization of programmable front-end resistors and a back-end audio equalizer.

A home video network, and a home video and data network, utilizing wireless protocol communications over coaxial cable (CX) are disclosed. In the home video network, a main network station (10) includes video processing functionality, such as one or more of a DVD player, personal video recorder (PVR), and a set-top box (STB) for cable or satellite television reception. The main network station (10) also includes a matched splitter (27) that receives coaxial cable (CX) inputs, and provides low-pass filtered and high-pass filtered output. The low-pass filtered output (LF) corresponding to video signals is provided to the video processing functionality (20) and the high-pass filtered output (HF) corresponding to wireless protocol communications is provided to a wireless access point function (22). Other network stations and combinations of functions are also disclosed, including those that utilize a function switch (25) to switch between network communications over coaxial cable (CX) and communications over an antenna (A), in either a single BSS mode or a double BSS mode.

The invention is applicable to the technical field of household electrical appliances and provides a vibration compensation method for a single-rotor compressor and a controller. The method comprises the following steps: acquiring a rotating speed set value omega* and a rotating speed estimated value omega e corresponding to a speed command value; multiplying a speed error delta omega by cos theta, carrying out low pass filtering so as to obtain the cosine component Qc of a speed fluctuation fundamental wave, multiplying delta omega by sin theta and carrying out low pass filtering so as to obtain the sine component Qs of the speed fluctuation fundamental wave; multiplying Qc by cos (theta+delta theta), multiplying Qs by sin (theta+delta theta) and adding the result of multiplication of Qc by cos (theta+delta theta) and the result of multiplication of Qs by sin (theta+delta theta) together so as to obtain an intermediate rotating speed omega rip; subjecting omega rip to high pass filtering so as to obtain a q-shaft current compensation value; and inputting the q-shaft current compensation value into the single-rotor compressor to realize vibration compensation. With the technical scheme provided by the invention, the advantages of reduction in vibration of the single-rotor compressor and easy realization are obtained.

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.

An interlaced to progressive scan video converter which identifies object edges and directions, and calculates new pixel values based on the edge information. Source image data from a single video field is analyzed to detect object edges and the orientation of those edges. A 2-dimensional array of image elements surrounding each pixel location in the field is high-pass filtered along a number of different rotational vectors, and a null or minimum in the set of filtered data indicates a candidate object edge as well as the direction of that edge. A 2-dimensional array of edge candidates surrounding each pixel location is characterized to invalidate false edges by determining the number of similar and dissimilar edge orientations in the array, and then disqualifying locations which have too many dissimilar or too few similar surrounding edge candidates. The surviving edge candidates are then passed through multiple low-pass and smoothing filters to remove edge detection irregularities and spurious detections, yielding a final edge detection value for each source image pixel location. For pixel locations with a valid edge detection, new pixel data for the progressive output image is calculated by interpolating from source image pixels which are located along the detected edge orientation.

Compensating for the misalignment of a navigation device with respect to a vehicle is described. In one example, the compensation is made by applying a high pass filter to a measured acceleration of the vehicle to produce a motion acceleration signal, weighting the motion acceleration signal with a measured steering rate of the vehicle, and deriving misalignment parameters for the navigation device with respect to the vehicle using the weighted motion acceleration signal.

Methods and systems are disclosed for reducing signal interference between Bluetooth (BT) and WLAN (e.g. WiFi) communications in an information handling system. The WLAN receiver has configurable front-end filter circuitry. Based upon information concerning the BT frequency region for current BT communications, the WLAN receiver can adjust or set its configurable front-end filter circuitry to filter out the BT communications. As the BT communications hop from frequency to frequency, the WLAN receiver can continue to adjust its configurable front-end filter circuitry accordingly. Example implementations for the configurable front-end filter circuitry include bandpass filters and selectable low pass and high pass filters. These filters are selected and/or tuned such that BT frequency regions are filtered from the WLAN input signal before further WLAN signal processing is conducted, thereby improving the performance of simultaneous BT and WLAN communications.

A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal that measures the ambient audio and an error microphone signal that measures the output of an output transducer plus any ambient audio at that location and injects the anti-noise signal at the transducer output to cause cancellation of ambient audio sounds. A processing circuit uses the reference and error microphone to generate the anti-noise signal, which can be generated by an adaptive filter operating at a multiple of the ANC coefficient update rate. Downlink audio can be combined with the high data rate anti-noise signal by interpolation. High-pass filters in the control paths reduce DC offset in the ANC circuits, and ANC coefficient adaptation can be halted when downlink audio is not detected.

An apparatus for concealing a highband error in a spilt-band wideband voice codec in accordance with the present invention is disclosed. The apparatus includes: a lowband LPC coefficient extracting unit for extracting a lowband linear predictive coding (LPC) coefficient from a lowband voice signal passed by a lowband decoding unit; a highband excitation signal generating unit for generating a highband excitation signal based on the lowband voice signal and the lowband LPC coefficient; a highband LPC coefficient generating unit for generating a highband LPC coefficient based on the lowband LPC coefficient; a highband voice synthesizing unit for synthesizing a highband voice signal based on the highband excitation signal and the highband LPC coefficient; and a high pass filtering unit for removing a lowband component of the synthesized highband voice signal by the highband voice synthesis unit and generating the synthesized highband voice signal.

A novel mechanism for performing high accuracy cable diagnostics. The mechanism utilizes time domain reflectometry (TDR) to detect and identify cable faults, perform estimations of cable length, identify cable topology, identify load and irregular impedance on metallic paired cable, such as twisted pair and coaxial cables. The TDR mechanism transmits pulses whose shapes are programmable and analyzes the signal reflections. The shapes of the pulses transmitted can be optimized in accordance with the channel characteristics. Further, the TDR mechanism is adapted to operative in the presence of high pass filters in the channel.

An adjustable equalizer that includes a first branch including a low pass filter (LPF) and having a variable gain (β), and a second branch including a high pass filter (HPF) and having another variable gain (α). Outputs of the branches in response to an input signal are summed to produce an equalized output. The equalizer can be implemented using CMOS technology so that the gain parameters β and α are independently adjustable and the equalizer is capable of equalizing an input indicative of data having a maximum data rate of at least 1 Gb/s. Typically, the inventive equalizer is embodied in a receiver for use in equalizing a signal, indicative of video or other data, that has propagated over a serial link to the receiver. In some embodiments useful for equalizing a differential input signal, the equalizer includes two differential pairs of MOS transistors and a controllable current source determines the tail current for each differential pair. The current sources are independently controllable. When the equalizer includes purely resistive impedances Z0 and Z1, the equalizer's transfer function is Z1/Z0.(β+α·(1+s·C0·Z0)), where β is a gain parameter determined by the tail current of one differential pair and α is a gain parameter determined by the tail current of the other differential pair.

A filter circuit is provided wherein one end of an inductor is connected to one end of a capacitor to form a signal input end. The other end of the inductor is connected to a first switch circuit, and the other end of the capacitor is connected to a second switch circuit. When a lower-frequency signal in a 2.4 GHz band is to be inputted, a low-pass filter circuit is formed by connecting the other end of the inductor to a signal output end and the other end of the capacitor to ground, and when a higher-frequency signal in a 5 GHz band is to be inputted, a high-pass filter circuit is formed by connecting the other end of the inductor to ground and the other end of the capacitor to the signal output end, by manipulating the first and second switch circuits.

A digital camera comprises a solid state imaging device provided with an optical low-pass filter. A photographing optical system forms an object image on a light receiving surface of a CCD through the optical low-pass filter. An electronic-charge accumulation-time control program is stored in a ROM of a system control circuit to determine optimum exposure parameters according to which a photography is performed. The electronic-charge accumulation-time control program has a program diagram showing a relationship between an electronic-charge accumulation-time and an aperture value and/or an ISO speed.

The present invention relates to a connector which includes a plug unit and a receptacle. The plug unit includes a housing board and a transmission path board. The housing board has a housing board body and first connection terminals and second connection terminals. The transmission path board has a transmission path board body, plural differential signal patterns which are connected to the first connection terminals and the second connection terminals of the housing board, and high pass filters which are connected to each of the differential signal patterns. The receptacle has a receptacle body and pin contacts. According to the present invention, a low-frequency component of a digital signal is attenuated. Thus, since an attenuation factor of the high-frequency component and an attenuation factor of the low-frequency component of the digital signal can be set substantially the same, the digital signal can be transmitted surely.

A high-frequency circuit for branching high-frequency signals for pluralities of communications systems of different frequencies, which comprises a lowpass filter circuit disposed between first and second ports and/or a highpass filter circuit disposed between the first port and a fourth port; and a matching circuit and a bandpass filter circuit disposed between the first port and a third port; the lowpass filter circuit, the highpass filter circuit and the matching circuit comprising capacitance elements and inductance elements; the bandpass filter circuit being a SAW filter; and the passband f1 of the lowpass filter circuit, the passband f2 of the bandpass filter circuit, and the passband f3 of the highpass filter circuit meeting the condition of f1<f2<f3.

A multiplexer, such as a diplexer, is delineated. The multiplexer may be employed in a communications system that may communicate in multiple frequency bands within a predefined range of frequencies, e.g., 2400 MHz-4900 MHz. The communications system may operate in a network, such as a wireless local area network, without significant interference from signals used by a cellular/mobile telephone system. The multiplexer may include multiple channels with bandpass filters that may be formed with lumped inductors and lumped capacitors. In at least one of the channels, the bandpass filter may be formed by combining at least one lowpass filter with at least one highpass filter.

The headset comprises: a physiological sensor suitable for being coupled to the cheek or the temple of the wearer of the headset and for picking up non-acoustic voice vibration transmitted by internal bone conduction; lowpass filter means for filtering the signal as picked up; a set of microphones picking up acoustic voice vibration transmitted by air from the mouth of the wearer of the headset; highpass filter means and noise-reduction means for acting on the signals picked up by the microphones; and mixer means for combining the filtered signals to output a signal representative of the speech uttered by the wearer of the headset. The signal of the physiological sensor is also used by means for calculating the cutoff frequency of the lowpass and highpass filters and by means for calculating the probability that speech is absent.

An energy management system that facilitates the transfer of high frequency energy induced on an implanted lead or a leadwire includes an energy dissipating surface associated with the implanted lead or the leadwire, a diversion or diverter circuit associated with the energy dissipating surface, and at least one non-linear circuit element switch for diverting energy in the implanted lead or the leadwire through the diversion circuit to the energy dissipating surface. In alternate configurations, the switch may be disposed between the implanted lead or the leadwire and the diversion circuit, or disposed so that it electrically opens the implanted lead or the leadwire when diverting energy through the diversion circuit to the energy dissipating surface. The non-linear circuit element switch is typically a PIN diode. The diversion circuit may be either a high pass filter or a low pass filter.

In a low-pass filter which is preferably used as a loop filter in a PLL or DLL, filter characteristics which are the same as those of a conventional low-pass filter are realized without causing collateral problems, such as an increase in the circuit area, the circuit complexity, or the resistance value, which may be caused due to size reduction of a capacitive element in the conventional low-pass filter. Thus, in a loop filter including a capacitive element and a resistive element which are connected in series, the first input terminal is provided at the side including the resistive element, and the second input terminal is provided at a connection point of the capacitive element and the resistive element. The first input terminal is supplied with the first electric current. On the other hand, the second electric current, which is a part of the first electric current supplied to the first input terminal, is extracted from the second input terminal, so that the electric current flowing into the capacitive element is smaller than the electric current flowing through the resistive element.

A filter system including a low pass filter having a response which rolls off towards a crossover frequency and a high pass filter having a complementary response which rolls off towards the crossover frequency. The responses are arranged such that the combined response of the filters is substantially constant in amplitude at least in the region of the crossover frequency. The response of the low pass filter is defined by a low pass complex transfer function having a first numerator and a first denominator. The response of the high pass filter is defined by a high pass complex transfer function having a second numerator and a second denominator. The desired response is obtained when the second denominator is substantially the same as the first denominator and the sum of the first and second numerators has substantially the same squared modulus as the first or second denominator.

A circuit and method for reducing noise in video imagers which takes advantage of the fact that the same image information is present in the drain current in a reset transistor used to reset a photodiode in a pixel as is present in the readout current. The noise is reduced by passing the multiplexed output voltage from the source follower output transistor in an APS imager system through a high pass filter to reduce the low frequency noise from the source follower. The drain current in the reset transistor used to reset the APS is passed through a low pass filter. The low pass filter output and the high pass filter output are then combined. Since the drain current in the reset transistor contains the same image information as the voltage output of the source follower output transistor the image information can be obtained by combining the output of the low pass filter and the output of the high pass filter. Since the low frequency noise components of the source follower output transistor have been suppressed combined outputs of the low pass filter and high pass filter will provide the image information with greatly suppressed low frequency noise.