2195 results about "Cutoff frequency" patented technology

An image pick-up apparatus and an image pick-up system constructed to prevent occurrence of random noise in a photographed image due to a random noise component produced in a reference supply circuit. An image pick-up apparatus has an area sensor driven by matrix driving, and a reference supply circuit for supplying a reference voltage for driving of the area sensor, and the reference voltage is supplied through a low-pass filter (LPF) coupled to the reference supply circuit. Further, a cutoff frequency of the low-pass filter preferably is determined so that an effective value of noise of the reference voltage having passed through the low-pass filter becomes not more than one-tenth of an effective value of random noise produced in pixels of the area sensor.

The present invention provides a cardiogram waveform correcting and displaying device capable of facilitating visibility of cardiogram waveforms. A first filtering means 58-1 through n th filtering means 58-n are low-cut filters, each having a first cutoff frequency fc1 through an n th cutoff frequency fcn respectively. Recognition means 56 recognizes feature values of waveforms related to variation of the waveforms in accordance with any outputs of the first filtering means 58-1 through the n th filtering means 58-n. Judging means 62 selects which of the first through the n th filter is used based on the recognized feature values with the recognition means 56. A filter which restricts base-line variation is used when the base-line variation is large, and a filter having less influence to waveforms is used when the base-line variation is small. Display control means 64 displays on a display portion 65 output of the selected filter.

Methods and devices for fabricating AlGaN/GaN normally-off high electron mobility transistors (HEMTs). A fluorine-based (electronegative ions-based) plasma treatment or low-energy ion implantation is used to modify the drain-side surface field distribution without the use of a field plate electrode. The off-state breakdown voltage can be improved and current collapse can be completely suppressed in LDD-HEMTs with no significant degradation in gains and cutoff frequencies.

A method of suppressing effects of aliasing in a system for digitally processing a high speed signal having a symbol rate of 1/T. The high speed signal is sampled at a fractional multiple (N) of the symbol rate, wherein 1<N<2, to generate a corresponding sample stream, and filtered using a low-pass filter characteristic having a cut-off frequency corresponding to 1/2T. Phase distortions due to the filtering are compensated by digitally processing the sample stream.

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.

A DSP-based and multi-channel digital filter chip providing crossover filtering and parametric equalization. Crossovers can be low-pass, high-pass, or band-pass filters with programmable cutoff frequencies. Each equalizer band has independently adjustable center frequency band, and levels over a -60 dB to +16 dB range. The chip can work either with a microprocessor controlling the chip or in a stand-alone mode having the filter settings downloaded automatically from an external EEPROM. The chip is ideal for applications that require precise digital filtering or software programmable filters, and is also an alternative to analog filters, eliminating passive components and reducing circuit size.

An optical element includes a first filter having the function to transmit a component at a lower frequency than a first cutoff frequency in incident light, a second filter having the function to transmit a component at a higher frequency than a second cutoff frequency in the incident light, and a light-receiving element for photoelectrically converting the components transmitted through the first filter and the second filter in the incident light. A metal optical filter composed of a conductor thin film is used as at least one of the first filter and the second filter.

A data modulator unit generates a DQPSK optical signal in accordance with a data signal. A phase shift unit provides a phase difference of π/2 between a pair of arms. A photodetector converts an output signal of the data modulator unit into an electrical signal. A filter is a low-pass filter with a cut-off frequency lower than a symbol frequency, and filters an output signal of the photodetector. A monitor unit detects power of an output signal of the filter. A phase difference control unit adjusts the amount of phase shift in the phase shift unit so as to minimize power of an output signal of the filter.

An audio processing apparatus includes first and second audio pickup units. The second audio pickup unit includes an audio resistor provided to cover a sound receiving portion to suppress external wind introduction while passing an external audio. A first filter attenuates a signal having a frequency lower than a first cutoff frequency of the output signal of a first A/D converter. A second filter attenuates a signal having a frequency higher than a second cutoff frequency of the output signal of a second A/D converter. A third filter is provided between the first audio pickup unit and the first A/D converter to attenuate a signal having a frequency lower than a third cutoff frequency for suppressing the wind noise.

An improved method for reducing the accuracy requirements on the starting model when performing multi-scale inversion of seismic data (65) by local objective function optimization (64). The different scales of inversion are brought about by incorporating a low-pass filter into the objective function (61), and then decreasing the amount of high-frequency data that is filtered out from one scale to the next. Moreover, the filter is designed to be time varying, wherein the filter's low-pass cutoff frequency decreases with increasing traveltime of the seismic data being filtered (62). The filter may be designed using Pratt's criterion for eliminating local minima, and performing averages (or other statistical measure) of the period and the traveltime error only with respect to source and receiver location but not traveltime (63).

The purely bound electromagnetic modes of propagation supported by waveguide structures comprised of a thin lossy metal film of finite width embedded in an infinite homogeneous dielectric have been characterized at optical wavelengths. One of the fundamental modes supported by the structure exhibits very interesting characteristics and is potentially quite useful. It evolves with decreasing film thickness and width towards the TEM wave supported by the background (an evolution similar to that exhibited by the sb mode in symmetric metal film slab waveguides), its losses and phase constant tending asymptotically towards those of the TEM wave. Attenuation values can be well below those of the sb mode supported by the corresponding metal film slab waveguide. Low mode power attenuation in the neighbourhood of 10 to 0.1 dB/cm is achievable at optical communications wavelengths, with even lower values being possible. Carefully selecting the film's thickness and width can make this mode the only long-ranging one supported. In addition, the mode can have a field distribution that renders it excitable using an end-fire approach. The existence of this mode renders the finite-width metal film waveguide attractive for applications requiring short propagation distances and 2-D field confinement in the transverse plane, enabling various devices to be constructed, such as couplers, splitters, modulators, interferometers, switches and periodic structures. Under certain conditions, an asymmetric structure can support a long-ranging mode having a field distribution that is suitable to excitation using an end-fire technique. Like asymmetric slab waveguides. The attenuation of the long-ranging mode near cutoff decreases very rapidly, much more so than the attenuation related to the long-ranging mode in a similar symmetric structure. The cutoff thickness of a long-ranging mode in an asymmetric finite-width structure is larger than the cutoff thickness of the sb mode in a similar asymmetric slab waveguide. This implies that the long-ranging mode supported by an asymmetric finite-width structure is more sensitive to the asymmetry in the structure compared to the sb mode supported by a similar slab waveguide. This result is interesting and potentially useful in that the propagation of such a mode can be affected by a smaller change in the dielectric constant of the substrate or superstrate compared with similar slab structures.

A power tool movement monitor system including a first accelerometer operatively configured to sense movement along a first axis of a power tool and a first high pass filter operatively connected to the output of the first accelerometer. The first high pass filter has an output and a cutoff frequency corresponding to a predetermined acceleration limit capable of being output by the first accelerometer. The power tool movement system further includes a logic circuit operatively configured to generate a warning signal when the first high pass filter outputs a signal having a frequency equaling or exceeding the cutoff frequency of the first high pass filter.