Hewlett-packard Development Company, L.P.

Tektronix, Inc.

Micropump, Inc.

Steven E Soar

William S Eaton

Ngoc-Diep Nguyen

Michael A Viselli

Matthew Allen Shepherd

Kevin D O'Hara

Carl D Beckett

Daniel B Olsen

Delbert L Rice

Jeffrey G Barton

Glenn E Siemer

An analog encoder of one embodiment of the invention is disclosed that includes an input mechanism, a digital signal processing mechanism, and an output mechanism. The input mechanism is to receive and digitize different analog encoder signals. The digital signal processing mechanism is to generate inverse analog encoder signals from the different analog encoder signals, and to apply dynamically changeable gain and offset corrections in real-time. The output mechanism is to generate digital quadrature signals from crossing points among the analog encoder signals and the inverse analog encoder signals, and a position value based on a direction of the digital quadrature signals for external access.

Analog encoder

An encoder includes a housing, a light source coupled to the housing, and a light sensor coupled to the housing and positioned to receive a light beam from the light source. The encoder also includes a wheel having opaque and transmissive sections which may be positioned to pass through the light beam before it reaches the light sensor. The encoder further includes a floating aperture piece, which defines at least one aperture. The aperture is positioned so that the light beam must pass through it before reaching the light sensor. The floating aperture piece slidably engages the housing while allowing a loose tolerance between a position of the wheel and a position of the housing, thereby substantially eliminating a positioning error between the aperture and the wheel.

Floating aperture encoder

A sensing mechanism for an image-forming device of one embodiment of the invention is disclosed that includes a first light source, a second light source, a detector, and a controller. The first light source is positioned incident to a first side of media, whereas the second light source is positioned incident to a second side of media opposite of the first side of the media. The detector is positioned incident to the second side of the media to detect first light transmitted through the media as output by the first light source, and to detect second light reflected off the media as output by the second light source. The controller is to detect at least one characteristic of the media based on a ratio of the first light to the second light.

Image-forming device sensing mechanism

A method of an embodiment of the invention is disclosed that advances media sheets through an image-forming device such that each successive pair of media sheets are advanced at least substantially adjacent to one another. The method transmissively optically senses a leading edge of each of the media sheets and a lagging edge of each of the media sheets. The method detects occurrence of an out-of-media sheets situation where a length of time after the lagging edge of one of the media sheets has been optically sensed exceeds a threshold length of time.

Transmissive optical sensing of leading edges of media sheets advanced substantially adjacent to one another

Encoder having a slidably engaged floating aperture piece

A system and a method are provided for velocity modulation to create pulseless delivery of a fluid by a pump, particularly a piston pump. The system and method require input of data, such as a user-entered dispense rate or analog current or voltage input proportional to a desired output rate. A timer or counter is pre-loaded from a lookup table stored in a processor. The time or counter is started and, upon detection of an overflow condition, the motor and table pointer are incremented one step. As a result, pulseless operation of a pump is achieved.

System and a method for velocity modulation for pulseless operation of a

A reciprocating piston pump provides pulseless delivery of liquid. It is suitable for use in compact environments or for the delivery of small amounts of liquid, as in chromatographic analysis devices. The pump includes two pistons with pumping chambers that are alternately connected to inflow and outflow lines through a control valve. The control valve moves between a first position in which inflow is directed to the first piston chamber and outflow to the second piston chamber, and a second position in which outflow is directed to the first piston chamber and inflow is directed to the second piston chamber. Each outflow pulse from the piston is sustained longer than each inflow pulse, and the outflow pulses are staggered and partially superimposed to provide substantially pulseless delivery of liquid from the pump. A rotating cam moves the pistons of the pumps and the control valve between their operating positions described above. The cam rotates at a constant speed around an axis that is parallel to the axis of movement of the piston pumps. A control surface is carried by and rotated by the cam in one embodiment. Grooves inscribed in the control surface establish and break fluid connections as the cam rotates.

Axial cam driven valve arrangement for an axial cam driven parallel

A low inductance probe contains a signal probe shaft having a signal probe point and an adjacent ground conductor or conductive shield for placing on the circuit location which is desired to be measured, a ground probe arm having a ground probe point for placing on a convenient ground location. The ground probe arm is attached to the signal probe shaft by means of a hinge which enable the ground probe arm to rotate between zero and approximately 135 degrees in a compass like fashion. The ground conductor of the signal probe shaft and the ground probe point of the ground probe arm are electrically connected by means of a low inductance ground lead consisting of a monolithic, flexible strand of conductive foil.

Adjustable low inductance probe

A low inductance ground lead for grounding a signal probe used in high frequency measurement to a ground probe. A ground lead comprises a single flexible strand or multiple strands which are substantially untwisted with respect to one another. Preferably, the strands have a rectangular cross-section and a relatively large surface area for a given cross-sectional area. Substantially noninductive connections for connecting one end of said ground lead to the signal probe and the other end of said ground lead to the ground probe are provided, so as to bypass the self-inductance of the signal probe and the ground probe.

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Vancouver, WA, United States of America

Steven E Soar