Hewlett-Packard Company

Hewlett-Packard Development Company, L.p.

William P Proctor

Leslie G Christie, Jr

Vernon L Knowles

Bruce W Schober

Steven L Brittenham

Ted A Brooks

Robert E Kier

Mark A Rau

A method for sensing position that comprises generating light, eclipsing the light according to position, sensing the amount of light not eclipsed, and inferring position according to the sensed amount of light.

Method and apparatus for sensing position of a tape head in a tape drive

A communication channel that is accessible when the product is entirely assembled, but appears to be, and functions like, configuration jumpers to the end user. The communication channel utilizes the terminals of a configuration jumper block as communication paths to an interface device. The terminals of the configuration jumper block may be wired differently depending on the desired function (i.e. send data, receive data, etc.) of the terminals. The configuration information needed by the device is read from the terminals of the configuration block when the communication channel is not active. Switches on the interface device are used to set the configuration information. Configuration jumpers that can be used are the Master, Slave, and Cable Select signals for an ATAPI interface.

Communication on non-continuously sampled lines

A method and apparatus for implementing a zero order hold function in the digital to analog conversion process in a digital control system reduces the phase lag contributed by the digital to analog conversion process relative to a conventional implementation of the zero order hold function. The apparatus for implementing the reduced phase lag zero order hold function employs a digital signal processor, a plurality of digital buffers, a digital multiplexing element, and a digital to analog converter. Phase lag is reduced by generating, from the digital to analog converter, for a fraction of the sample period, a waveform having a constant analog voltage with an amplitude which is scaled by the reciprocal of said fraction relative to a conventional zero order hold function. During the remainder of the sample period a substantially constant offset analog voltage is generated by the digital to analog converter. Alternatively, the time compression and amplitude scaling required to implement the reduced phase lag zero order hold function can be performed within the digital signal processor in the digital control system.

Method and apparatus for reducing phase lag resulting from digital to

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Boise, ID, United States of America

William P Proctor