Abstract: An inlet/exhaust valve having a cylindrical portion with a cavity therethrough for use in a pneumatic control valve is disclosed. The inlet/exhaust valve has at least two seats, one of which is on an inner diameter of the cylindrical portion and the other of which is on an outer diameter of the cylindrical portion. Both seats are rounded for self-aligning seating with corresponding seating surfaces.

Abstract: A disc drive actuator system includes an equalizer filter coupled between the controller and actuator plant of a disc drive actuator system. The filter applies a gain of less than unity gain to the actuator drive signals from the controller at the resonance frequency of the plant, and applies a gain greater than unity to the actuator drive signals at a selected frequency different from the plant resonance frequency to derive a system resonance frequency shifted from the plant resonance frequency. In one form the equalizer filter functions as a notch filter to attenuate signals at the plant resonance frequency, and functions as a peak filter to boost the gain of higher frequency signals over a band wide enough to ensure zero phase loss below the plant resonance frequency.

Abstract: An apparatus and method for compensating actuator arm oscillation induced by resonance mode excitation during a seek in a disc drive data handling system. The actuator arm supports a head adjacent a recording surface, and a servo loop controls the position of the actuator arm. A frequency of actuator arm oscillation is identified, after which a seek is initiated to move the head from an initial track to a destination track on the recording surface. A position error signal (PES) is generated to indicate position of the head relative to the destination track, and a compensation signal is generated by a filter based on the PES and the frequency of oscillation of the actuator arm. The compensation signal is adapted to remove a component of the PES arising from the actuator arm oscillation, and is applied to the servo loop as the head is settled onto the destination track.

Abstract: Method and apparatus for more accurate track following. Control circuitry rotates a data storage surface containing thousands of annular tracks. A “measured” subset of the tracks is selected so as to be interspersed with an “unmeasured” subset. The calibration profile is derived based on position error signals each obtained by reading from the measured subset and not from the unmeasured subset. Data from the unmeasured subset of tracks is ignored, in generating and/or updating the profile.

Abstract: A circuit and method thereof for arbitrating between a first power source and a second power source in a computer system peripheral device such as a network adapter (e.g., a network interface card) that is connected to multiple power sources. The circuit includes a field effect transistor (FET) and a diode integral with the FET coupled between the first power source and the second power source. The FET is adapted to conduct current from the second power source when power is not available from the first power source, and to substantially prevent current from flowing from the first power source to the second power source. The circuit also includes a voltage regulator coupled between the first power source and the second power source, adapted to regulate voltage such that a voltage from the first power source and a voltage from the second power source are approximately equal.

Abstract: A circuit and method thereof for arbitrating between a plurality of power sources connected to a computer system peripheral device. The circuit includes a first circuit subassembly coupled to a first power source and a second power source. The first circuit subassembly conducts current from the first power source when power is not available from the second power source, and otherwise conducts current from the second power source. The circuit also includes a second circuit subassembly coupled between the first circuit subassembly and a third power source. The second circuit subassembly conducts current from the third power source when the third power source is available and otherwise conducts current from the first circuit subassembly. The second circuit subassembly comprises a first component, a second component and a third component. The first component is coupled to the third power source and the first circuit subassembly.

Abstract: A transmit packet buffer (TPB) is used on a network interface card (NIC) to store downloaded packets and forward them through the media access controller (MAC) and the physical layer interface (PHY) onto the wire. A multi-function TPB is implemented to allow the multiple usage of this buffer. Packets may be downloaded to this buffer through multiple sources. Different types of the packets may each be stored at predefined locations. For example, while the second half of the TPB is used to transmit keep-alive or alert-on-LAN packets, the first half may be used to compare received packets with a wake-up pattern for system wake-up. With multi-function support, various PC management functions may be implemented more effectively and with reduced cost.

Abstract: A system for positioning a read/write head having a voice coil suitable for coarse control and a piezoelectric transducer (PZT) suitable for fine control. A voice coil control signal and a PZT control signal are generated from a position-indicative signal, both receiving power via a shared supply having a nominal rectified voltage V1. In a preferred method, control signals are both applied to the voice coil and PZT when amplified so that each has a saturation voltage smaller than |V1|.

Abstract: A digital sine/cosine wave generator generates discrete values representative of either a sine wave or a cosine wave. The digital sine/cosine wave generator generates sine and/or cosine waves by implementing a difference equation of the form y(n)=b*y(n−2)−y(n−1). One of the initial conditions of the difference equation is selected from a series of values generated by a coefficient generator. The frequency of the sine and/or cosine wave generated by the sine/cosine wave generator is dependent on, and may be selected according to, which of the series of values generated by a coefficient generator is chosen as an initial condition of the difference equation.

Abstract: A circuit and method thereof for indicating availability of a power source other than a first power source in a computer system peripheral device (such as a network adapter) connected to a plurality of power sources including. The circuit includes a circuit subassembly coupled to the first power source and a second power source. The circuit subassembly conducts current from the first power source when power is not available from the second power source and otherwise conducts current from the second power source. A first component is coupled to the circuit subassembly and conducts current when the second power source is available; otherwise, it does not conduct current. A second component is coupled to the circuit subassembly and to the first component. The second component conducts current when the first component is conducting current and otherwise does not conduct current.

Abstract: A system for positioning a read/write head having a voice coil suitable for coarse control and a piezoelectric transducer (PZT) suitable for fine control. A voice coil control signal and a PZT control signal are generated from a position-indicative signal, both receiving power via a shared supply having a nominal rectified voltage V1. In a preferred method, control signals are both applied to the voice coil and PZT when amplified so that each has a saturation voltage smaller than |V1|.

Abstract: A simplified, quick exhaust assembly is provided for a proportional modulator for an electropneumatic braking system. A proportional valve has an enlarged diameter opening that permits direct communication between the delivery port and the exhaust port of the assembly. The opening is dimensioned to be substantially equal to the valve seat area provided by the piston and either meets or exceeds quick exhaust times over present arrangements.

Abstract: Support for priority and IP security packets, and other protocols at the network interface level and in conjunction with FIFO-based packet buffers is provided by allowing out of order processing of certain packets in the FIFO. The optimized character of FIFO for sequential transfer is maintained, while particular types of packets are processed out of order to achieve minimum latency and maximum data security in an intelligent network interface card. A buffer stores data packets in an order of receipt. Logic is included in the network interface to transfer packets out of the buffer according to the order of receipt, and according to the respective packet types so that packets having a particular packet type are transferred out of the order of receipt relative to packets having other packet types.

Abstract: A self-cleaning feature is provided for a trailer ABS modulator. Direct exhaust is provided through the piston or diaphragm to establish control line and control volume drain capabilities. This provides for moisture removal from the control line or control volume. Quick exhaust during normal service braking is also improved and, likewise, exhaust during the ABS mode is improved.

Abstract: A noise reducer for a valve having a quick release function is disclosed. The noise reducer is preferably an open-celled structure that is impervious to dirt, moisture, alcohol, and oil, and acts as both a dampener and a biasing spring to reduce the oscillations of an exhaust diaphragm in an ABS modulator and urge the diaphragm toward a closed position. The open-celled foam is preferably an annular configuration so that it does not interfere with the amplitude of displacement of the diaphragm.

Abstract: An improved, air tight valve seat for a pneumatic brake system is achieved by using a plastic valve seat that is coined by the valve member. The valve member is a harder material, for example metal, than the thermo-plastic valve seat. The valve member is brought to an elevated temperature less than the melting point of the valve seat. The valve member engages the valve seat, coining the desired surface of the valve seat to conform it to the valve member. The heated valve member then remains in the valve assembly after coining.

Abstract: A modulator valve for an ABS system for heavy duty vehicles is disclosed. It uses non flow-through solenoid valve assemblies that simplify the machining and manufacturing costs associated with the present arrangement. This eliminates complex pilot passages and also achieves a quicker acting release of the brakes during normal service braking.

Abstract: A transmit packet buffer device capable of asynchronous read and write functions is used for receiving frame data from a host and forwarding the data over a network. The device comprises dual-ported memory capable of independent write and read access, a plurality of registers for storing address pointers to locations in the memory, and a logic device coupled to the dual-ported memory and the plurality of registers for controlling downloading data into the memory at a first clock speed, and transmitting data from the memory at a second clock speed. The registers are used to store memory addresses for reference by the logic device, and the data is divided into frames.

Abstract: An ABS modulator solenoid valve (10), having one electric solenoid (12), in which the valve control piston (14) has a passage (16) therethrough for balancing the pneumatic pressure on both ends (34, 36) of the control piston (14). One end (34) of the piston (14) is disposed in a closed piston chamber (32) while the other end (36) is positioned to contact and position a valve spool (40). The passage (16) extends between the ends (34, 36) of the piston (14). Piston (14) is biased by a spring (50) to a position within the piston chamber (32). When the solenoid (12) is de-energized the piston (14) remains in this position and variable air pressure, from an operator controlled brake valve (126), can be supplied through the valve (10) to a brake chamber (128) for operating the vehicle service brakes. During an ABS application the solenoid (12) is energized to overcome the inlet spring (50) bias and the piston (14) moves into engagement with the valve spool (40).

Abstract: The combination solenoid valve and shuttle valve (60) with self-cleaning orifice (92) comprises a shuttle valve (50) which is slidingly and sealingly received at an end (40D) of the solenoid valve (40). The shuttle valve (50) includes a stepped interior opening (54) which includes an insert (55) providing a shuttle valve seat (91) opposite a self-aligning solenoid valve seat assembly (94) of the solenoid valve (40). The valve seat (91) of the shuttle valve (50) includes an orifice (92) which extends from an end opening (70) of the insert and communicates with an insert passage (63) at an outer radial portion of the insert (55). An opposite radial side of the insert (55) includes a port (67) which communicates with a longitudinal passage (66) of the insert (55). Disposed within the longitudinal passage (66) is a brake-master cylinder check valve (59), and a stabilization check valve (58) adjacent a filter element (80) which permits communication with the insert passage (63).