Abstract:
An inverting power supply (10) having first and second charging capacitors (22, 24) that are alternately connected to a positive power source (12) and a negative output terminal (18) which is to be maintained at a negative voltage with respect to a common ground for the power source and the power supply. Switches (34, 36) connect a positive plate of each charging capacitor to the power supply positive terminal during alternate half cycles of a two-phase clock (20) and charge is bled from the positive plates by switching transistors (46, 50) during the other half cycle to enable charge to be transferred via diodes (52, 54) from the negative output terminal to negative plate of the charging capacitors during the other half cycle. The base-emitter currents of the switching transistors are controlled by a charge transfer control circuit (56) in relation to the voltage at the negative output terminal to regulate the voltage at the negative output terminal by controlling the rate of charge transfer to the negative output terminal. Additional regulation can be provided by a current control circuit (106) that adjusts the switching transistor base-emitter currents in relation to the collector currents of the switching transistors.
Abstract:
A magnetically permeable material comprising a substantially amorphous permalloy film is disclosed. The substantially amorphous permalloy film is formed by ion-beam sputtering. The substantially amorphous permalloy film exhibits improved output amplitude and noise characteristics.
Abstract:
A disc drive wherein at least two outer tracks of the disc in a region (15) beyond the defined track 0 are used to store the drive operating microprogram, and/or manufacturing test program, and/or specific electrical, mechanical and magnetic parameters and media defect information. This data can be read from these outer tracks of the disc during initialization of the disc drive, or during seek operations of the drive to immediately adjust the positioning of the read/write head. It allows the disc drive to react to microprogram problems without changing either the mask ROM or an EPROM supplied. The microprogram is read onto the drive over the I/O interface.
Abstract:
A digital peak detector for detecting those peak member values of either polarity in a digitized values sequence having magnitudes greater than, or in some instances equal to, each of those in a selected number of neighboring member values which can selectively be required to be of the same polarity as the corresponding peak value, subject to exceeding both a selected absolute threshold and a selected multiple of a subsequent sequence member value. A peak value and polarity notifier provides a selected one of two alternative indicator pairs of signals of selectable time durations to indicate the occurrences of peak value members and the polarity thereof. The magnitudes of future member values in the digitized values sequence obtained from an analog signal are adjusted by varying the magnitude of that signal based on a magnitude average of selectively weighted differences between a number of past peak member values and a desired value. These differences available for use in this averaging are subject to being excluded if associated with known system operation problems but other member values are subject to being included if too much time has elapsed since the previous difference value based adjustment. Magnitude asymmetries between peak member values of different polarities in the digitized values sequence are compensated by adding and subtracting therefrom based on a magnitude average of these differences after those associated with member values in the digitized values sequence of one polarity are negated and all in the average are selectively weighted. Value based on these magnitude averages are stored for selective use as initial average values for the corresponding next such averaging. Magnitudes over time of the digitized values sequence related to paired zones along tracks in the magnetic medium disk in a magnetic data storage and retrieval system are accumulated and subtracted from one another for each pair. The accumulated difference results for each pair are used as an error signal for estimating the lateral position error with respect to the track of the "read head" in retrieving information from the stored magnetic data on the disk.
Abstract:
A hydrodynamic bearing with shaft (10) and hub (12) in which the bearing is open at both the upper and lower ends, and in which the balance of fluid flow within the bearings is maintained.
Abstract:
A hydrodynamic bearing having a fixed central shaft (108) carrying first and second conical bearings (104, 106) separated by a central circular shaft portion of the shaft and lubricated by first and second circulation paths (101, 102) circulating through a central reservoir (120) in the shaft. The first and second conical bearings taper outwardly from the central shaft. Further, the hydrodynamic bearing includes a sleeve (110) which rotates relative to the fixed shaft, the sleeve includes a first concave bearing surface (113) rotatably overlying a convex surface of the first conical bearing and forming a first gap in the first circulation path. The sleeve further includes a second concave bearing surface (115) rotatably overlying a convex surface of the second conical bearing and forming a first gap in the second circulation path. The reservoir contains lubricating fluid which communicates with the first and second convex bearings through second and third bores extending from the reservoir toward the radially extending surfaces.
Abstract:
A disc drive (10) having an actuator arm (16) to support a slider (24) carrying a transducing head (56) adjacent a selected data track (34) of a disc (30) having a plurality of concentric data tracks (34) includes a microactuator (54) on a leading edge surface (60) of the slider (24) to effect fine positioning of the transducing head (56) with respect to the selected track (34). The microactuator (54) includes a spatial region (63, 65) on the leading edge surface (60) of the slider (24). A microactuator element (72, 74, 92, 94, 142, 172) spans the spatial region (63, 65) and is responsive to a voltage to selectively expand and contract, thereby bending to alter the position of the slider (24) and the transducing head (56).
Abstract:
A slider (36) supports a transducer (44) proximate to a lubricated recording medium (16). The slider (36) includes a slider body, a raised rail (38, 40) formed on the slider body and a fluid flow pattern across the slider body which has at least one stagnant flow region (70, 72, 74, 76). A surface discontinuity (80, 82, 84, 86, 92, 102, 110, 112, 114, 116, 122, 130, 138) is formed on the slider body and is positioned within the stagnant flow region (70, 72, 74, 76) to inhibit lubrication (78, 79) collected within the stagnant flow region (70, 72, 74, 76) from migrating to the raised rail (38, 40).
Abstract:
An apparatus encodes data blocks into code blocks, each code block containing more symbols than its respective data block. The apparatus includes a data block latch (30) for receiving individual data blocks and for dividing each data block into two sub-blocks. An encoder (32) receives one of the data sub-blocks and encodes the first data sub-block as a code sub-block. An interleaver (34, 36), coupled to the encoder (32) and the data block latch (30), combines the code sub-block with the second data sub-block to produce a code block, such that when the code blocks are concatenated with each other to produce a string of code symbols no more than five consecutive occurrences of a particular code symbol are present in the string of code symbols.