Hewlett-packard Company

Other

Richard A Baumgartner

Charles E Moore

John N Dukes

Travis N Blalock

Earl C Herleikson

Thomas Hornak

George A Fisher

Ian Bennett

Rajeev Badyal

Mark Taylor Smith

Richard D Pering

David Merlin Beard

Larry S Metz

Ran-Fun Chiu

Sui-hing Leung

Thomas M Walley

Li Ching Tsai

Thomas A Shoup

Richard A Baugh

Robert A Zimmer

James S Ignowski

Kenneth R Stafford

Earl C Herlelkson

Joey Doernberg

A method for transferring signals from a photoreceiver array to computational circuitry in which parallel transfer amplifiers receive periodic offset correction. In a first embodiment, each transfer amplifier has a differential circuit that can be switched from a reset mode to a readout mode. In the readout mode, the voltage state at the output is responsive to first and second inputs, with the second input being connected to a source of a reference voltage. In the reset mode, the inputs are both connected to the reference voltage and the output is temporarily connected to a source of a fixed reset voltage. An offset adjustment signal is generated in response to detection of a voltage difference between the reset voltage and the actual voltage state at the output after the output has been disconnected from the source of the reset voltage. A single offset circuit is used to periodically and sequentially refresh the various transfer amplifiers.

Offset removal circuitry for photoreceiver signals

Circuitry and circuitry layout are provided to achieve a high percentage of photoreceiver area to total area and to stabilize the voltage at the base node of a phototransistor. Voltage stabilization is achieved by a servo circuit in which a negative feedback loop from the base node to an emitter node maintains a bias point, so that photocurrent is efficiently delivered to charge transfer circuitry. In the preferred embodiment, the base node is connected to a gate of a first transistor having a drain that is connected to a source of constant current and to a gate of a second transistor that functions as a source follower. The source of the second transistor is connected to the emitter node of a phototransistor. As photocurrent is generated by the reception of light, an integration capacitor is charged. The relatively high percentage of photoreceiver area to total area is achieved by contributions from a number of factors, including the design of the servo circuit, use of a single transfer amplifier to service an entire row of phototransistors, and pairing the phototransistor circuits in order to permit efficient sharing of common circuit paths and circuit components.

Low differential light level photoreceptors

An analog, fully integrated, partial response maximum likelihood (PRML) read channel utilizing a high-performance analog delay line, an analog adaptive equalizer and an analog Viterbi detector is provided, resulting in saved space, performance gains, and lower power consumption. For signal detection and reconstruction used in read operations, the partial response maximum likelihood (PRML) read channel includes a variable gain amplifier coupled to a lowpass filter for input to an adaptive analog equalizer. The adaptive analog equalizer comprises an analog delay line and an analog feedforward equalizer (FFE). An analog Viterbi detector employs maximum-likelihood sequence estimation (MLSE) techniques to performs the signal detection function. A decoder/descrambler produces a final reconstructed signal. The analog implementation of a partial response maximum likelihood (PRML) read channel also includes a scrambler/encoder coupled to a write precompensation circuit for output to a separate write head.

Analog implementation of a partial response maximum likelihood (PRML)

A method and device for tracking relative movement between the device and a region of interest include correlating a reference frame of signals with a subsequently acquired sample frame of signals, with the correlating including generating a correlation output for each of a number of nearest-neighbor shifts of signals of one of the frames. Preferably, the frames are comprised of a two-dimensional array of pixels and the signals are pixel values. The pixels of a frame are operatively associated with photoelements in a two-dimensional array of photoelements, with the pixel values being indicative of light energy received at the photoelements. By correlating the reference frame and the sample frame using the nearest-neighbor approach, it is possible to determine the movement of an imaged feature during the time period between acquisition of the reference frame and acquisition of the sample frame. In the preferred embodiment, the pixel values of the reference frame may be selectively shifted to correspond to the movement of the image feature, allowing the nearest-neighbor approach to continue even after the relative movement exceeds a pixel length. Also in the preferred embodiment, the device is a scanner having a second photoelement array. The second photoelement array captures image data which is position-tagged by navigation data acquired by means of the correlation of reference and sample frames.

Method and device for tracking relative movement by correlating signals

Circuitry and method for transferring signals from a photoreceiver array to computational circuitry includes parallel transfer amplifiers that receive periodic offset correction and includes DC removal amplifiers. In a first embodiment, each transfer amplifier has a differential circuit that can be switched from a reset mode to a readout mode. In the readout mode, the voltage state at the output is responsive to first and second inputs, with the second input being connected to a source of a reference voltage. In the reset mode, the inputs are both connected to the reference voltage and the output is temporarily connected to a source of a fixed reset voltage. An offset adjustment signal is generated in response to detection of a voltage difference between the reset voltage and the actual voltage state at the output after the output has been disconnected from the source of the reset voltage. A single offset circuit is used to periodically and sequentially refresh the various transfer amplifiers. In a second embodiment, spatial frequency components at both low and high frequencies are removed from the outputs of the photoreceiver array by DC removal amplifiers. Each DC removal amplifier is assigned to a particular photoelement in the array, but receives outputs from one or more other photoelements in the array. The output of the amplifier is responsive to the differences between the analog signals input to the amplifier.

Offset removal and spatial frequency band filtering circuitry for

A mixed analog and digital integrated circuit with features which are especially useful for application as a front end for physiological signal instrumentation such as electrocardiographs, electromyographs, and electroencephalographs. The integrated circuit has 5 signal channels, each with analog amplification and analog to digital conversion. The channels can be configured for various combinations of input signal amplification, input signal summation, analog output driving, and AC impedance measurement. The integrated circuit has 2 digital serial input lines and 2 digital serial output lines, all designed for direct connection to optical couplers. Channel configuration, gain, and other parameters are externally controllable by a serial digital input signal. Up to 6 compatible devices can be serially connected in a chain.

Serial processing circuits with serial chaining

Integrated circuit for physiological signal measurement

Signal processing circuits with digital programmability

Analog to digital converter with autoranging offset

Switched capacitor circuit for precision resistance

Biomedical amplifier circuit

A delay circuit comprising a plurality of cascaded saturating circuit elements is provided. The delay circuit may be incorporated in such circuits as modulators and demodulators to provide signal delay.

Testing and calibrating of amplitude insensitive delay lines

A transversal filter is provided which includes a delay circuit comprising a plurality of cascaded saturating circuit elements. The delay circuit has a series of taps from which signals with varying delays are obtained. The obtained signals are combined to form filtered signal(s).

Amplitude insensitive delay lines in a transversal filter

Amplitude insensitive delay line

A delay circuit for providing signal delay within an acoustic imaging system is provided. Reflected acoustic signals are transformed into electrical signals and are used to reproduce images of objects. Delay lines along the electrical signal path are used to focus the images compensating for asynchronism of electrical signals caused by variations in the length of acoustic signal paths.

Amplitude insensitive delay lines in an accoustic imaging system

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Palo Alto, CA, United States of America

Richard A Baumgartner