Abstract: A mixer apparatus (60), such as an integrated circuit (IC) mixer is provided for improving the physical layout of devices containing mixers. The mixer includes a multiplier (62) with an input port (64), an output port (66), a first switchable local oscillator input port (68) and a second switchable local oscillator input port (72). The dual switchable local oscillator ports are located on either side of the mixer, between the input side and the output side. The dual switchable local oscillator ports allow the mixer to provide more flexibility in integrated circuit and printed circuit board design layouts involving mixer apparatus. For example, in dual channel devices, a local oscillator can be coupled to a pair of the mixers using transmission lines that do not have to be routed around the integrated circuit, to a different level of the printed circuit board or underneath one of the mixers.

Abstract: The present invention provides methods and apparatus for calibrating and controlling output power levels in a broadband communication system. The power level of an intermediate frequency (IF) signal may be varied at a first attenuator. The IF signal from the first attenuator may be frequency converted at a mixer to provide a desired transmit frequency converted signal. The power level of the frequency converted signal may be adjusted at a second attenuator. The signal may be sampled after the second attenuator in order to detect its output power level. The detected output power level may be compared with a reference level to obtain a difference signal. The difference signal may be used in a feedback loop to adjust the power level of the signal output from the first attenuator so that a constant output power level is maintained. Methods and apparatus for calibrating output power levels are also provided.

Abstract: A disk drive having an embedded servo disk format preferably having a fixed-number of radial servo sample wedges per track, in which data blocks are located independently of the servo sample wedge locations of any particular track, and can be split around servo sample wedges. Thus, a fraction of a data block, or more than one data block, can be written between consecutive servo sample wedges, beginning almost anywhere in a data wedge. Each data sector has an associated identification (ID) field that includes at least one segment descriptor. Each segment descriptor describes the data segments into which a data block can be split. Provision is made for as many segment descriptors as there can be data segments for a data block. In general, a segment descriptor is a multi-bit digital signal that defines the absolute or relative location of split data segments (or, alternatively, the absolute or relative length of split data segments, from which the location can be determined).

Abstract: An over center closure apparatus for a spring latched rock door for a combine harvester includes a first, free rotating lever arm connected to rotate about the rock door pivot and a second lever arm connected to rotate with the rock door pivot. The second lever arm includes a stop positioned to engage the first lever arm as it rotates about the rock door pivot. A linkage arm extends from the first lever arm downward to a over center lever arm in an over center assembly. The over center lever arm is positioned to rotate about a pivot axis between an over center position and a free rotating position such that, when the over center lever arm is rotated to the over center position, the rock door is closed and held in the closed position by the over center position of the over center lever arm. The rock door can then be conveniently latched closed.

Abstract: A phase-locked system for recovering data from a disk drive includes a phase detector for signalling the difference in phase between incoming delayed data pulses and a phase detection window clock signal. The phase detection window clock signal is derived from one output of an integrated-circuit window generator, driven by the output of a voltage-controlled oscillator whose frequency is controlled by the phase detector. The phase-locked loop is completed by comparing the phase detection window clock signal output of the window generator with the incoming delayed data pulses in the phase detector. Data detection window clock pulses, defining time windows in which the delayed data pulses are exactly centered, are produced at a second output of the window generator which has a line about which it is essentially symmetric, resulting in the two outputs of the window generator being exactly 180.degree. apart in phase from each other.

Abstract: A phase-locked system for recovering data from a disk drive includes a phase detector for signalling the difference in phase between incoming delayed data pulses and a phase detection window clock signal. The phase detection window clock signal is derived from one output of a phase shifter driven by the output of a voltage-controlled oscillator whose frequency is controlled by the phase detector. The phase-locked loop is completed by comparing the phase detection window clock signal output of the phase shifter with the incoming delayed data pulses in the phase detector. Data detection window clock pulses, defining time windows in which the delayed data pulses are discerned, are produced at a second output of the phase shifter. The phase shifter produces a delay variable in precise increments over a wide range, causing a variable phase relationship between the time windows and the delayed data pulses that are to be discerned therein.

Abstract: An integrated system for use in a disk drive system for the implementation of write precompensation for recording of data and read window margining for accelerated testing of the disk drive. Both functions are provided by a common delay-line circuitry. The output of the delay line circuit is applied to both window shifting and write precompensation. An on-board read detection error analysis can be performed after installation of the drive in a computer system in its final configuration. Actual read error tolerance based on the overall system in its actual operating condition can thus be obtained. Enhanced data recovery techniques are also facilitated.

Abstract: Three versions of a gear box for a combine corn head are illustrated. The gearing to drive a pair of snapping roll shafts and a pair of gathering chain drive shafts are housed in two casings releasably secured to one another in an end-to-end relationship.

Abstract: A flat panel display for video and/or information display including a geometric array of individually energizable, low energy electron emitters in combination with an array of continuous channel electron multipliers for amplifying and directing the electron outputs of the emitters onto a phosphor screen to emit visible light.

Abstract: In aid of a person transporting a narrow oblong object traversing obstacles of various heights, the object is supported at one end by a single wheel disposed adjacent the dihedral intersection of a narrow end and a narrow longitudinal side, the rotational plane of the wheel coinciding with a plane of weight symmetry of the narrow oblong object to reduce tipping tendency when support and propulsion is provided by the person manually at an end opposite the wheeled end. Various means are disclosed for coupling the single wheel to the narrow oblong object, including concave socket and clamp means. Adjustment is provided for coinciding wheel rotational plane with the plane of weight symmetry.