526 results about "Signal transfer function" patented technology

A disk drive is disclosed comprising a voice coil motor (VCM) driven in a PWM mode using model reference current feedback. The PWM circuitry and VCM form a plant transfer function which varies with changes to the plant characteristics, such as the resistance of the voice coil fluctuating with temperature drift. A plant model having a model transfer function generates an estimated state of the VCM in response to a detected current flowing through the voice coil. A correction block, responsive to the detected current, adjusts PWM timing signals so that the plant transfer function substantially matches the model transfer function.

A single channel full duplex wireless communication system includes a processor, a transmitter, a receiver, a secondary transmission path, a combining element, a primary transmission feedback path and a secondary transmission feedback path. The transmitter transmits a transmission signal via a transmission path. The receiver receives a received signal via a reception path. The transmitter and the receiver utilize one channel to transmit and receive signals. The transmission signal causes self-interference. The processor estimates a first transfer function and feeds the secondary transmission path with the transmission signal adjusted by the first transfer function to reduce the transmission signal leaked to the reception path. The combining element combines the transmission signal with the adjusted secondary transmission path signal to remove the self-interference. The primary transmission feedback path output is modified by a second transfer function. The secondary transmission feedback path output is modified by a third transfer function.

The present invention provides extended depth of field or focus to conventional Amplitude Contrast imaging systems. This is accomplished by including a Wavefront Coding mask in the system to apply phase variations to the wavefront transmitted by the Phase Object being imaged. The phase variations induced by the Wavefront Coding mask code the wavefront and cause the optical transfer function to remain essentially constant within some range away from the in-focus position. This provides a coded image at the detector. Post processing decodes this coded image, resulting in an in-focus image over an increased depth of field.

Loudspeaker systems for handheld devices (2400, 2500) such as cellular telephones (100, 1400, 1600, 1900) are provided. The loudspeaker systems include at least one omnidirectional monopole loudspeaker (404, 1504, 1802, 1918, 1920) and at least one dipole loudspeaker (402, 1502, 1804, 1914, 1916). Filtering is used to compensate for differences between electric-to-acoustic signal transfer functions of the loudspeakers in order to achieve destructive interference of emitted audio in one direction and reinforcement in another direction. Various loudspeaker systems that are reconfigurable from directional mode, to omnidirectional mode are provided. Filtering is also used to add a frequency dependent phase to one signal in order to alter a direction of maximum sound pressure level. Two monopole-dipole pairs can be used to produce a stereo effect. The monopole and dipole loudspeakers can be housed in a detachable loudspeaker accessory (200).

A system for increasing the depth of field and decreasing the wavelength sensitivity of an incoherent optical system incorporates a special purpose optical mask into the incoherent system. The optical mask has been designed to cause the optical transfer function to remain essentially constant within some range from the in-focus position. Signal processing of the resulting intermediate image undoes the optical transfer modifying effects of the mask, resulting in an in-focus image over an increased depth of field. Generally the mask is placed at or near an aperture stop or image of the aperture stop of the optical system. Preferably, the mask modifies only phase and not amplitude of light, though amplitude may be changed by associated filters or the like. The mask may be used to increase the useful range of passive ranging systems.

A continuous time Bandpass Delta Sigma (DELTASIGMA) Modulator architecture with feedforward and feedback coefficients to completely specify both the signal transfer function (STF) and the noise transfer function (NTF) for a stable modulator ADC system.

A method of presenting an audio signal to a user of a mixed reality environment is disclosed. According to examples of the method, an audio event associated with the mixed reality environment is detected. The audio event is associated with a first audio signal. A location of the user with respect to the mixed reality environment is determined. An acoustic region associated with the location of the user is identified. A first acoustic parameter associated with the first acoustic region is determined. A transfer function is determined using the first acoustic parameter. The transfer function is applied to the first audio signal to produce a second audio signal, which is then presented to the user.

An audio signal processing method comprises the steps of emitting a sound at a virtual sound image location in space on the outer side of a closed surface, generating measurement-based directional transfer functions corresponding to a plurality of positions on the closed surface based on a result of measuring the sound at the plurality of respective positions on the closed surface by using a directional microphone, generating composite transfer functions corresponding to the plurality of respective positions on the closed surface by respectively adding, at a specified ratio, the measurement-based directional transfer functions and auxiliary transfer functions and generating reproduction audio signals corresponding to the plurality of respective positions on the closed surface by performing a calculation process on an input audio signal in accordance with the set of composite functions.

A superconducting quantum interference devices (SQUID) comprises a superconducting inductive loop with at least two Josephson junction, whereby a magnetic flux coupled into the inductive loop produces a modulated response up through radio frequencies. Series and parallel arrays of SQUIDs can increase the dynamic range, output, and linearity, while maintaining bandwidth. Several approaches to achieving a linear triangle-wave transfer function are presented, including harmonic superposition of SQUID cells, differential serial arrays with magnetic frustration, and a novel bi-SQUID cell comprised of a nonlinear Josephson inductance shunting the linear coupling inductance. Total harmonic distortion of less than −120 dB can be achieved in optimum cases.

A method of controlling a sigma delta modulator with a loop which establishes a signal transfer function, STF, and a quantization noise transfer function, NTF, of the sigma delta modulator, wherein the sigma delta modulator receives an input signal, x(n), and provides a modulated output signal, y(n) in response to the input signal. The method is characterized in comprising the step of controlling the sigma delta modulator to change the quantization noise transfer function, NTF, in response to a signal feature, A(n), which is correlated with the input signal.

An object of this invention is to provide a power supply apparatus, which realizes a frequency characteristic of an open-loop transfer function having a trap point, and can deal with input fluctuation. A controller of the power supply apparatus of the invention is a circuit in which although the form of its transfer function is the same as a conventional one, values of respective coefficients are different, only a phase margin is ensured without ensuring a gain margin, and the transfer function is realized which provides a frequency range (i.e. trap point) in which a decrease in gain is remarkable and a phase is considerably delayed. Besides, in order to ensure the stability against input fluctuation, a power conversion circuit is used which converts an input voltage from an input DC power supply so as to be constant in multiplying voltage by time.

Operational data is utilized to determine the FEXT interference induced by one line into the other DSL line. FEXT interference can be calculated using the NEXT interference measured between the two lines at the upstream ends of the loops and the downstream channel transfer function of one of the loops. Because the NEXT and transfer function constitute a linear time-invariant system, as does the FEXT interference between the lines, the NEXT interference and line transfer function can be multiplied (if in linear format) or added (if in logarithmic format) to approximate the FEXT interference between the lines. The collection of data, calculations and other functions performed in these techniques may be performed by a system controller, such as a DSL optimizer. An Xlog(u,n) quantity is a decibel-magnitude representation of the insertion-loss equivalent of FEXT transfer functions and is defined as the ratio of (1) a line u's source power into a matched load of 100 Ohms when no binder is present to (2) the power at the output of the subject line when line u is excited with the same source and the binder is present. Xlin(u,n) is the linear equivalent of Xlog(u,n). The Xlog(u,n) and Xlin(u,n) quantities may be represented in specific formats that assist in their use in DSL and other systems. When defined as a line's insertion loss, Xlin (or equivalently Xlog) does not include the effect of any transmit filter.

The A/D converter device includes a comparing section and an abnormality judging section. The comparing section compares a voltage of its signal transfer line connected between its input multiplexer and its A/D converting section through its sample-hold section with a predetermined abnormality judging voltage. The abnormality judging section is configured to apply a reference voltage to the signal transfer line in synchronization with an A/D conversion cycle thereof on condition that its A/D converting operation thereof is not interrupted, and to determine presence of abnormality in the A/D converter device if an comparison result of the comparing section does not match an expected value corresponding to the reference voltage.

The invention provides a weld surface defect identification method based on image texture. Miniature CCD camera photographing parameters are set according to the acquisition image standard; an acquired true color image is converted into a grey-scale map, and a gray scale co-occurrence matrix is created; 24 characteristic parameters in total, including energy, contrast, correlation, homogeneity, entropy and variance, are respectively extracted in the direction of 0 degree, 45 degrees, 90 degrees and 135 degrees, and normalization processing is performed on the extracted characteristic parameters; a BP neural network is trained by utilizing a training sample image, and the number of neurons of the neural network, a hidden layer transfer function, an output layer transfer function and a training algorithm transfer function are set; test sample characteristic parameters are outputted to the trained BP neural network to perform classification and identification; and the matching degree of the test sample and different types of surface welding quality training samples is calculated so that automatic classification and identification of the test sample surface welding quality can be completed.

A sound processing apparatus includes a sound collection position calculating unit configured to calculate sound collection positions of sound signals of multiple channels on the basis of the sound signals, a sound source direction calculating unit configured to calculate a sound source direction on the basis of the sound signals of multiple channels, a first transfer function calculating unit configured to calculate a first transfer function corresponding to the sound source direction on the basis of the sound signals of multiple channels, and a second transfer function calculating unit configured to calculate a second transfer function by interpolating the first transfer function corresponding to each of a plurality of sound source directions.

A method of enhancing vertical polar localization of a head related transfer function (HRTF). The method includes splitting an audio signal and generating left and right output signal by enhancing a left lateral magnitude of the respective signal by determining a log lateral component of the respective frequency-dependent audio gain that is equal to a median log frequency-dependent audio gain for all audio signals of that channel having an desired one of the plurality of perceived source locations. A vertical magnitude of the respective audio signal is enhanced by determining a log vertical component of the respective frequency-dependent audio gain that is equal to a product of a first enhancement factor and a difference between the respective frequency-dependent audio gain at the desired one of the plurality of perceived source locations and the lateral magnitude of respective audio signal. The output signals are time delayed according to an interaural time and delivered to left and right ears of a listener.

In a method for channel estimation of an OFDM signal transmitted via a channel, an initial channel transfer function is calculated by channel estimation. A channel impulse response is calculated on the basis of the initial channel transfer function. Values of the channel impulse response or of a filtered channel impulse response are classified as noise or as a signal as a function of the level of the values of the channel impulse or of the level of the values of the filtered channel impulse response. A noise-reduced channel impulse response is calculated on the basis of the channel impulse response using the classification, and a noise-reduced channel transfer function is calculated on the basis of this noise-reduced channel impulse response.

A video coding device may be configured to receive receiving video data generated based on a range mapping error. A range mapping error may result from a luminance transfer function corresponding to High Dynamic Range (HDR) video data being using to transform video data that is not HDR. The video coding device may be configured to mitigate the range mapping error. The video coding device may remap video data. The video coding device may perform coding techniques that mitigate that the remapping error.

The present invention relates to automatic registration and tracking of the eyes of at least one subject. An optical system, including a lens structure, a mask and an image sensor, receives incoming light from a scene containing the subject and directs at least a portion of this light towards the image sensor, which registers spatially distributed light and thus produces primary data. The mask is adapted to alter a basic optical transfer function of the lens structure and the image sensor into an enhanced optical transfer function, which is substantially less sensitive to variations of an unknown distance between the optical system and the subject than the basic optical transfer function. The processing unit is adapted to receive the primary data and process this data to produce resulting eye-tracking data representing a position estimate of the at least one eye and/or a gaze direction for the at least one eye.