Abstract: An optical mouse images as an array of pixels the spatial features of generally any micro textured or micro detailed work surface below the mouse. The photo detector responses are digitized and stored as a frame into memory. Motion produces successive frames of translated patterns of pixel information, which are compared by autocorrelation to ascertain the direction and amount of movement. A hold feature suspends the production of movement signals to the computer, allowing the mouse to be physically relocated on the work surface without disturbing the position on the screen of the pointer. This may be needed if the operator runs out of room to physically move the mouse further, but the screen pointer still needs to go further. The hold feature may be implemented with an actual button, a separate proximity detector or by detecting the presence of a characteristic condition in the digitized data, such as loss of correlation or velocity in excess of a selected limit.

Abstract: A selected length of antenna for a device under test is placed within a conductive inner cylinder, forming an unterminated “input” coaxial transmission line. The inner cylinder is in turn within and coaxial with a conductive outer cylinder, forming an “output” transmission line. The inner cylinder is the center conductor of the output transmission line, and in a region extending beyond the extent of the antenna therein, conically tapers to being a normal center conductor of solid cross section. The outer cylinder matches this taper to maintain a constant characteristic impedance Z0out (say, 50 &OHgr;) for the output transmission line, which then delivers its output signal to a matched terminating load in measurement equipment via either a coaxial connector or an interconnecting length of auxiliary transmission line.

Abstract: A solution to the problem of I/O card faults caused by spurious RF energy induced by ESD related currents in the vicinity of an aperture in a chassis is to reduce the efficiency of the radiating antenna created by the aperture and decouple any remaining spurious RF energy from any would-be receiving antenna in the I/O card. A conductive boot covers the I/O cable as it emerges from the chassis. The boot is physically attached and AC coupled (as well as probably ohmically connected) to the chassis at one end and tapers down to a small aperture at a distal end to permit egress of the I/O cable. The aperture at the distal end is considerable smaller than the aperture at the chassis, which is no longer visible to ESD induced currents anyway, since its edge has been replaced by the surface of the boot. The smaller aperture is a less efficient antenna at the frequencies of interest and it is now further removed from components that might act as receiving antennae.

Abstract: The thermal resistance to lateral flow of heat flux through the lid of a semiconductor package may be reduced by incorporating one or more heat pipes into the lid itself. This has the further benefit of reducing the effective thermal resistance of the mechanical interface between the lid of the package and an external heat sink, owing to an increased area over which the heat flux is conducted. The result is a reduced temperature at the source of heat inside the semiconductor package.

Abstract: Multi-channel measurement equipment enters or performs a special mode of operation in response to an arbitrarily chosen probe being momentarily touched to a special terminal. A signal identifiable by its uncommon properties is present at the special terminal. The uncommon signal is generated by a suitable circuit, which may be similar to a pseudo random sequence generator. Each channel is equipped with a recognition circuit that recognizes the presence of the uncommon signal. The recognition circuits each receive a copy of the uncommon ID signal, and the task of recognition is performed by pattern matching over time. To enter or perform the special mode the operator touches the probe to the special terminal. After a suitable but brief period of time the recognition circuit for that probe produces an output that indicates recognition. The measurement equipment responds by entering or performing the special mode of operation.

Abstract: A digital oscilloscope automatically selects as the initial instance of a waveform parameter to be measured the instance that is both visible in the displayed trace and closest to the trigger reference point. Such a manner of automatic selection allows a greater amount of panning and zooming while the 'scope is subsequently stopped, without causing a different instance to become the measured instance, and also reduces confusion about continuity of measurement while the display is altered with the 'scope is still running. This automatically selected choice can still be overridden, if desired, by a manual selection. A further refinement is to, once an instance is automatically selected, retain it as the selected instance as long as it remains visible as part of a modified displayed trace, even if it would not otherwise become the selected initial instance if the measurement activity were first initiated with that modified trace.

Abstract: A mouseless, optical and position translation type screen pointer control images a portion of the texture or fingerprint on one of the user's digits, which may be a thumb or a finger. Motion of the digit produces motion of the image that is detected by a movement sensor and is translated into corresponding motion of the screen pointer. The digit is placed onto an end of a rod lens that either extends upward amongst the keys: say, proximate the junction of the "H", "J", "Y" and "U" keys; or, horizontally outward from the front edge of the keyboard. As the image "moves" within the movement sensor a portion of it disappears from the field of view, and is replaced with other image patterns. A sufficiently changed image is maintained as a new current image, which then itself changes, and so on. A comparison between a reference frame (previous image) and the current frame (present image) allows detection of the amount and direction of image motion.

Abstract: Multi-channel measurement equipment identifies probe-to-channel correspondence by providing an identification (ID) terminal that can be touched by a probe whose channel correspondence is sought. A ID signal identifiable by its uncommon properties is present at the ID terminal. The uncommon ID signal is generated by a suitable circuit, which may be similar to pseudo random sequence generator. Each channel is equipped with a recognition circuit that recognizes the presence of the uncommon ID signal. The recognition circuits each receive a copy of the uncommon ID signal, and the task of recognition is performed by pattern matching over time. To discover a probe's channel identity the operator touches the probe to the ID terminal. After a suitable but brief period of time the recognition circuit for that probe produces an output that indicates recognition. The measurement equipment may display a message on a screen to the effect that the system has noticed that the probe for channel "X" is on the ID terminal.

Abstract: A solution to the problem of undesired serialization of bus controlled instrument measurement delays for multiple instances of programmatically controlled measurement processes is to configure the bus operations and the control programs to allow the issuance of a command within the context of a first collection of such instruments, without having to wait for the corresponding data before issuing commands within the context of a second collection. This is done by instructing the equipment in the collection to signal that they have data instead of the more customary immediately issued "@ address talk", which is then followed by the delay needed by the equipment to make the measurement. Instead, the "have data" signals are associated with the devices that originated them and then the bus instructions that request the data are issued. In conjunction with this, the usual bus I/O commands in the controlling programs may be replaced with calls to a library that operates in just this fashion.

Abstract: An air gapped inductance and a capacitance form a series resonance that is itself in series with a flourescent tube. The resulting series resonant network is permanently connected to one (+) side of the DC supply, while the other end is switched between that (+) side of the DC supply and the other (-) side of the DC supply. Switching occurs in synchronism with the different polarities of the half-cycles for the current circulating in the resonant circuit. In series with the current in the resonant circuit is the primary of a phase splitter driver transformer having separate secondaries phased to control FET switches to do the aforementioned switching, and whose turns ratios are selected to determine the duty cycles with which the resonant circuit is switched. The switched end is connected to the one (+) end of the DC supply for its entire associated half cycle.

Abstract: A self-framing serial trigger within an oscilloscope or specialized analyzer construes an absence of the data's clock signal for at least a selected length of time as implying the occurrence of a framing signal. This frees the serial trigger from otherwise needing an externally supplied framing signal. The serial trigger may include a shift register containing the most recent N-bits of the data, which is then bit-wise compared to the trigger pattern (stored in a register). This level of comparison may provide for don't care bits in the trigger pattern. The results of this bit-wise comparison are then inspected for a certain uniformity indicating that the trigger pattern has been matched. An additional circuit may count clock signals since the last implied framing pulse. If this additional count has not yet reached M (or counted down from M to zero) the match is premature, and no trigger signal is generated.

Abstract: A scanning mouse has two optical navigation sensors to allow measurement of both translation and rotation of the scanning mouse. It also has an image sensor, and the ability to digitize the sensed image data. There may be a second image sensor at perpendicular to the first. A high speed digital data path connects the scanning mouse to the computer. Software in the computer processes image line data that includes the locations of the navigation sensors and the digitized image data to produce partial scanned images that are further assembled into a complete image within the environment of the computer. Each optical navigation sensor images as an array of pixels the spatial features of generally any micro textured or micro detailed work surface below the mouse. The photo detector responses are digitized and stored as a frame into memory. Motion produces successive frames of translated patterns of pixel information, which are compared by autocorrelation to ascertain the direction and amount of movement.

Abstract: Good shielding in shielded peripheral connectors is maintained by including an EMI by-pass gasket between the cable connector and the card connector. The EMI by-pass gasket is a thin but resilient piece of metal somewhat larger than the outline of the connector to connector interface. It has a orifice therein that allows it to be between the connectors as they mate. Interior folded tabs along the edges of the orifice and parallel to the length of the connectors make compressive contact with the outer surface of the connector rim of the cable connector. A front surface or step around the backshell of the cable connector pushes the gasket toward the I/O card bulkhead plate, compressing a pair of opposing bent legs running the length of the gasket against the system enclosure. This provides a low inductance direct RF connection from the rim of the cable connector to the system enclosure (chassis), and in the process, by-passes (shunts) the ground path through the I/O card itself.

Abstract: An inverting amplifier having variable gain in M discrete steps that are a fixed ratio F apart may be constructed by grounding the non-inverting input of a high gain differential gain element, and connecting the inverting input through a single-pole M-throw switch to the N.sup.th terminal in a ladder network of M cascaded elements. Each element is a series R and X, with X grounded, and their junction being where the next element of the ladder is connected. These junctions are also the aforementioned terminals of the ladder network, and are what are coupled to the M throws of the switch. At an input end of the ladder network is another impedance Z, to which the input V.sub.in is applied. At the other end of the ladder network is a final R in series with another Z that is driven by the V.sub.out obtained from the output of the gain element. Once Z and F are selected R and X may be found according to the relationships R=Z[.sqroot.(1/F)-1]and X=Z[.sqroot.(1/F)]/[.sqroot.(1/F)-1].

Abstract: A solution to the problem of determining the degree of visibility for a bounding volume is to first sort the bounding volumes into an order in which they can be tested, after which they are rendered as if they were polygons in their own right. Prior to the testing of the next bounding volume a Bounding Volume Visibility (BVV) mode is enabled. This temporarily suspends write operations to the frame buffer and it resets a TOTAL PIXEL COUNTER and a VISIBLE PIXEL COUNTER. Then the polygon sides of the bounding volume are rendered, with each and every pixel of those polygons being checked for depth, as would be the pixels for "real" polygons. Each such pixel rendered causes an increment of the TOTAL PIXEL COUNTER, while each such pixel that meets the depth criteria in use causes an increment of the VISIBLE PIXEL COUNTER. The BVV mode is subsequently turned off, and the values of the two counters inspected. The inspecting entity may be software associated with the graphics application.

Abstract: A VLSI IC's signals as they appear at the signal via pads on the back side of a mother board may be probed with the aid of a backing plate that is a piece of multi-layer printed circuit board material thick enough to be sufficiently stiff for the purpose. The multi-layer PCB backing plate has front side pads and vias in at least those locations in the LGA (of signal via pads) corresponding physically to signals that are of interest for probing, and if such a subset is unknown ahead of time, the entire LGA of signal vias pads may be represented in the vias. An LGA socket connects the front side vias of the backing plate to the LGA of signal vias on the back side of the mother board carrying the gate array or other IC. Thus, those signals that, in the absence of a backing plate, could be probed on the back side of the mother board can now still be probed at back side pads on the back side of the PCB backing plate, just as if that were the back side of the mother board.

Abstract: A low noise fan reduces the production of turbulent vortices created by the passage of the fan's blade tips through the air by providing an annular venturi that is attached at its inner surface to the blade tips, and that thus rotates with those blades as a unit. This prevents high pressure air at the blade tips from spilling into low pressure air. The outer surface of the rotating venturi may have a close fit against the inner surface of an outer annular stationary housing of the fan, to minimize any acoustic or mechanical mischief created by the otherwise exposed outer surface of the rotating venturi.

Abstract: A portable wedge probe for perusing the signals of an IC is produced by mounting a short row of wedges in a housing that serves the dual purposes of: (1) Allowing the gripping and manipulation of the wedges for inspection, the connecting and unconnecting of interconnecting cables, deployment onto, and removal from, the IC; and (2) serving as the housing for and physical location of electrical interconnection(s) between the portable wedge probe and the cable(s) of the measurement (test) equipment. By the term "short row of wedges" we mean, say, two adjacent wedges for the signal on a single intervening interior pin of the IC, up to perhaps nine adjacent wedges for the eight signals on the eight intervening interior pins of the IC, as opposed to having the row of wedges being long enough to engage the entire side of the IC. The portable wedge probe is free standing once applied, and does not rely upon support from another row of wedges deployed on a different side of the IC.

Abstract: A ripple through divider of a dividend by a constant is obtained by cascading a plurality of partial quotient tables. Each table incorporates the same divisor, so the divisor need not appear as an input. In one binary integer implementation for an n bit dividend that dividend is represented as n+1 bits having an MSB of 0. If the binary divisor is of k bits, then the most significant k+1 bits are applied to an input of a first partial quotient table. It produces one bit of fractionary quotient that becomes the MSB of the final quotient, and k bits of fractionary remainder. That fractionary remainder is combined as MSB's with an LSB that is the next and most significant unused dividend bit. This forms k+1 inputs to a second partial quotient table. It in turn produces a partial quotient bit that becomes the second most significant final quotient bit, and k-many more fractionary remainder bits. The cascading continues with additional stages of partial quotient tables until all dividend bits have been used.

Abstract: A backing plate facilitates electrical probing of VLSI IC signals in an array of signal via pads on the back side of a printed circuit board and which correspond to an LGA of socket pads on the front side of the printed circuit board. The backing plate is constructed of electrically non conductive mechanically stiff material that already has drilled therein a hole for each signal via pad that might be probed. Polyamide is a suitable material for such a backing plate. Special symbols, legends and suitable grid identification axes can be silk screened onto the side of the backing plate that remains visible when installed. The drilled insulative backing plate can be equipped with captive threaded studs, if desired. Alternatively, it may simply have holes to receive fasteners, or have captive female threaded fasteners in lieu of holes.