Abstract: A system and method for calibrating amplifier gain and a comparator threshold for use in verification of magnetic media integrity in a magnetic data storage device. Commercially available read data processors are used which have an amplifier with controllable gain and a comparator with an internal indirectly-controllable threshold. An on-board voltage reference is provided for gain calibration. The calibrated gain is used to provide signals with known peak values for calibrating the comparator threshold. In one embodiment, the numeric control value for the threshold is reduced from a calibrated peak value to a specified fraction for media verification. In a second embodiment, the gain is reduced to the industry specified fraction and the threshold is calibrated to match peak signal magnitudes at the reduced gain. The gain is then returned to the calibrated level for media verification.

Abstract: A mixed analog and digital integrated circuit with features which are especially useful for application as a front end for physiological signal instrumentation such as electrocardiographs, electromyographs, and electroencephalographs. The integrated circuit has 5 signal channels, each with analog amplification and analog to digital conversion. The channels can be configured for various combinations of input signal amplification, input signal summation, analog output driving, and AC impedance measurement. The integrated circuit has 2 digital serial input lines and 2 digital serial output lines, all designed for direct connection to optical couplers. Channel configuration, gain, and other parameters are externally controllable by a serial digital input signal. Up to 6 compatible devices can be serially connected in a chain.

Abstract: A method for determining when overall lamp intensity is stable for a lamp in a document scanner. The intensity of a relatively small portion of the lamp is controlled as part of a closed loop intensity control system. During a warm-up transient period, the intensity of the small portion of the lamp is monitored and power to the lamp is monitored. A changing power to the lamp indicates that the overall lamp intensity has not stabilized. Scanning is initiated when the intensity of the monitored portion of the lamp is within a predetermined control range and the power to the lamp has stabilized for a predetermined time period. The predetermined time period can be a default value or can be determined by a user.

Abstract: A mixed analog and digital integrated circuit with features which are especially useful for application as a front end for physiological signal instrumentation such as electrocardiographs, electromyographs, and electroencephalographs. The integrated circuit has 5 signal channels, each with analog amplification and analog to digital conversion. The channels can be configured for various combinations of input signal amplification, input signal summation, analog output driving, and AC impedance measurement. The integrated circuit has 2 digital serial input lines and 2 digital serial output lines, all designed for direct connection to optical couplers. Channel configuration, gain, and other parameters are externally controllable by a serial digital input signal. Up to 6 compatible devices can be serially connected in a chain.

Abstract: A system and method for using N unidirectional lines to implement signals for arbitration, variable length transactions, automatic responses, and efficient burst transaction modes for a bus in a cache-coherent multi-processor computer system having N processors. Processors use arbitration lines to implement busy signals for variable length transactions. A processor needing to respond to a transaction is granted automatic access to a bus if it is the last processor asserting a busy signal. A processor in a burst transaction mode is granted automatic continuous access without arbitration if no other processors request access. The use of only N lines minimizes pin-out for an integrated processor. The use of unidirectional (one driver, N-1 receivers) lines further optimizes cost and speed.

Abstract: A probe fixture for making multiple high frequency connections to an electronic device under test. An application for the apparatus is in integrated circuit wafer testing fixtures requiring high frequency signals. Low frequency signals are attached by ribbon cables to a printed circuit board. High frequency signals use coaxial cables. A probe carrying ceramic substrate has microstrips for the high frequency signals. Low frequency signals are connected from the printed circuit board to the ceramic substrate by a conductive elastomer interconnect strip clamped between the printed circuit board and the substrate. Coaxial adapters passing through the printed circuit board have spring loaded center conductors to provide pressure contact between the coaxial cables and microstrip signal strips. In one embodiment, contact between coaxial cable shields and microstrip ground is through a conductive clamp to a substrate backplane.

Abstract: An integrated circuit packaging system with an integrated circuit die mounted onto a substrate having a top side ground plane between the integrated circuit and the substrate, a bottom side ground plane and short high frequency connections between the two ground planes. The top side ground plane decreases signal degradation due to reflections by providing high frequency ground access close to the die and by providing a transmission line for bond wires. A grid of conductive vias through the substrate improves thermal conductivity and provides the short high frequency current path for the top side ground plane. The die is separated from the top side ground plane by a dielectric layer which also has a conductive layer next the die to provide a back bias voltage.

Abstract: A mixed analog and digital integrated circuit with features which are especially useful for application as a front end for physiological signal instrumentation such as electrocardiographs, electromyographs, and electroencephalographs. The integrated circuit has 5 signal channels, each with analog amplification and analog to digital conversion. The channels can be configured for various combinations of input signal amplification, input signal summation, analog output driving, and AC impedance measurement. The integrated circuit has 2 digital serial input lines and 2 digital serial output lines, all designed for direct connection to optical couplers. Channel configuration, gain, and other parameters are externally controllable by a serial digital input signal. Up to 6 compatible devices can be serially connected in a chain.

Abstract: A method and apparatus for inserting a computer network protocol analyzer into a Token Ring network. Commercial integrated circuits are used to initiate a standard protocol test and synchronization sequence and to actuate an insertion relay in a network coupling unit. After actuation of the insertion relay, incoming network data is switched onto outgoing network data lines, bypassing the commercial protocol circuitry. As a result, the analyzer can be inserted into a Token Ring even when there are network problems which would prohibit insertion under normal protocol.

Abstract: A method and apparatus to improve memory performance in a computer bus system. Memory is divided into interleaved blocks and memory addresses are mapped into block identification numbers. Master devices keep track of which parts of memory are busy by storing memory block identification numbers in local queues whenever memory is accessed. Block identification numbers are removed from local queues when the memory transaction is complete. Master devices arbitrate for access to the bus for memory transactions only if the target memory block identification number is not in the local queue.

Abstract: An integrated circuit package with plastic or glass reinforcement of leads to increase lead rigidity, to improve lead alignment and positional stability, and to prevent bent leads. The invention is particularly applicable to surface mount packages. For plastic packages, plastic between the leads is formed during molding of the plastic package. For metal packages, the plastic is molded as a separate operation. For ceramic packages with lead frames, glass may be formed as a separate operation or may be formed at the same time as a glass seal for the ceramic package. Reinforcement can optionally be thicker than the leads for increased rigidity. Optional extended lead lengths enable plastic or glass to be formed on either side of the soldered foot area of each lead. No changes to test fixtures or to pick and place equipment are required.

Abstract: An optical beginning-of-tape detection device with automatic threshold adjustment. In a first embodiment, at two different locations on a tape, a comparator threshold is varied until the comparator switches states. The two locations are sufficiently far apart to guarantee that at least one measurement is not at the beginning-of-tape indication area. The greater of the two thresholds is used, with a predetermined offset for noise margin. In a second embodiment, the threshold is continuously adjusted through a diode across the comparator inputs. The threshold is initialized by moving the tape sufficiently far to guarantee that at some time during initialization the sensor is not at the beginning-of-tape indication area.

Abstract: A method and circuitry for controlling priority of devices contending for access to a data communications link. Each device capable of contending for access contains a priority register which indicates the relative priority of every device capable of contending for access. After gaining access to the link, a device may optionally signal to all devices to update priority. When priority is updated, the device signaling priority update is moved to lowest priority. Inhibiting the signal to update priority permits a device to maintain priority. Systems using the method may be configured with a fair arbitration protocol (least recently accessed has highest priority), with fixed priority protocol, or with priority protocols that can be modified in real time.

Abstract: A method and apparatus to improve computer bus access time. A bus is described which has sequential control states and fixed transaction times. Without the invention, arbitration may be delayed as the bus sequences through control states. With the invention, arbitration is immediate if the bus is idle. When any transaction is initiated, a counter is initialized to the number of control states in the standard transaction time. If the counter reaches zero, the bus is idle. If the bus is not idle, a sequence of bus control states is repeated. If the bus is idle, the bus is forced to remain in an arbitration state, thereby enabling any subsequent arbitration to take place immediately.

Abstract: A modular tray assembly for computer mass storage devices such as disk and tape drives. The assembly can be inserted through an opening in the back of a computer without requiring removal of a main computer housing cover. Power is automatically connected when the tray assembly is fully inserted into the computer. Control and data signals are connected via an external cable. Mass storage devices with removable media are accessible through an opening in the front of the computer.

Abstract: A modular adapter assembly for installing circuit boards in a computer system. The adapter assembly, with an attached industry standard circuit board meeting ISA, EISA, or MicroChannel specifications, can be inserted into a computer system through an opening in the back of the computer. The adapter assembly permits insertion and removal of circuit boards without requiring removal of a major computer housing cover and without requiring removal of attached signal cables.