Abstract: A video decompression system for decompressing consecutive streams of compressed video data to provide a continuous, uninterrupted decompressed video data output stream. The system is comprised of a plurality of decompression circuits, each circuit having a compressed video data buffer, a decoder, and a decompressed video data buffer. Each of the compressed video data buffers is coupled to an input switch and each of the decompressed video data buffers is coupled to an output switch. A controller operates the system. Decompression can occur simultaneously in all of the decompression circuits. This simultaneous decompression results, when necessary, in each decompression circuit having several frames of decompressed video data available for immediate display before that decompressed video data is actually required.

Abstract: A light emitting diode has both end faces metallized and is mounted on a substrate with the light emitting junction perpendicular to the substrate. The electrically conductive ends are electrically bonded to conductive areas on the substrate by solder or conductive adhesive. LED dice can be placed on the substrate by temporarily attaching the dice to a tape which has been wrapped around a knife edge. The dice tilt as the tape wraps around the edge and are picked off one at a time by a vacuum collet while temporarily supported by a movable finger, and then transferred by the vacuum collet to a substrate. A similar method may be used for placing semiconductor dice on a substrate without the tilting of dice around the edge. In another embodiment, an array of LEDs can be assembled in windows through a metallized plastic tape which is bonded to a foundation with additional metallized leads.

Abstract: An out of lock condition is sensed on a data transition by transition basis in clock recovery apparatus. When an out of lock condition is sensed, a range sweeping signal is generated and summed with the correction signal to sweep the frequency of the clock signal over the frequency range of the VCO. When an out of lock condition is absent, i.e., when the VCO is phase locked, simulated data transitions are generated in the frequency/phase detector. An out of lock condition is sensed by a D flip-flop. Data is coupled to the clock input of the flip-flop, the clock signal is delayed by a fraction of its nominal period and coupled to the D input of the flip-flop. The state of the Q output of the flip-flop indicates an out of lock condition.

Abstract: A fiber-optic system includes a photodetector for receiving optical signals from a light source, a threshold producing circuit coupled to the photodetector, and a delay block coupled to the photodetector. The threshold producing circuit produces a decision threshold voltage in response to signals from the photodetector. The delay block, formed of one or more stages of all-pass filter, delays the signals from the photodetector. The outputs of the delay block and the threshold producing circuit are connected to the inputs of a comparator. By providing a delayed signal, the decision threshold voltage is established in the comparator before the delayed signals reach the comparator. In this manner, pulse width distortion is largely eliminated in the first bit of data in burst mode data and the dynamic range of the overall system is preserved. In some cases, a multi-staged delay causes DC offset error in the delayed signal to the comparator.

Abstract: A bipolar transistor amplifier with improved base biasing is disclosed. In the bias circuit of the present invention, the bias current only varies with the log(log) of variations in .beta. of the NPN transistors, making the circuit particularly resistant to temperature and process induced variations in .beta.. A feedback loop also insures that the bias current will remain constant under normal operating conditions. In several embodiments of the present invention, the bias signal and the input signal are kept separate, reducing interference. The amplifier and bias circuit provides a large amount of voltage headroom even with low supply voltages.

Abstract: A power management system for a portable computer is disclosed. The system can determine which one of a plurality of battery packs has been coupled to the system. After determining the type of battery pack, the system recalls from storage the recommended charging pattern for the particular battery pack and begins to charge the battery at the recommended rate. The system's information is used during charging to determine if the battery pack is defective. When the computer is running off the battery pack, the charge counter measures the total amount of charge supplied to the computer and provides this information to the system. When the difference betweem the total amount of charge supplied to the computer and the total charge available from the battery reaches a predefined limit, the system indicates to the computer that a low-power situation exists and that the computer should prepare for a possible loss-of-power event.

Abstract: A metal frame is fabricated from magnesium alloy and all the main components of the computer, including the logic board, the hard disk drive, the keyboard, the upper and lower halves of the computer's case, and the pivoting display screen are all directly attached to the frame. The frame thus offers a method for constructing a personal computer which will have greatly improved shock resistance, integrated electromagnetic isolation, and structural strength, without increasing the weight of the completed computer in any significant fashion. Additionally, by means of a cooling flange fabricated as part of the frame, the central processing unit of the portable computer is thermally connected to the frame, which then acts as a heat-sink for the central processing unit, greatly improving its reliability.

Abstract: An improved backlighting system for electronic displays that require such backlighting is disclosed. The system comprises a fluorescent lamp with improved visible light generating means and a reflector means for channeling the light generated by the lamp into the electronic display. In particular, the lamp comprises, in a preferred embodiment, a cylindrical glass housing, sealed at both ends and containing a plasma which can be excited to generate short wavelength light. A strip of phosphorescent material is placed along the inside surface of the tube, the strip being relatively restricted in width, its width being partially determined by the thickness of the electronic display. A reflector surrounds the lamp and helps drive the light the lamp generates into the phosphor. The lamp is also comprised of a glass transparent to the frequencies of light generated by the plasma.

Abstract: A collapsible keyboard for use with portable personal computers is disclosed. A first preferred embodiment of the present invention comprises a keyboard molded from a conductive, elastomeric material and a collapsible frame/circuit board substrate, the substrate having a plurality of electrical contacts to indicate to the computer when a key is pressed. As the keyboard is formed from an elastic material, it can be compressed into a first, closed position of minimum size to facilitate carrying the computer and to minimize the computer's size. In the keyboard's second, expanded position, each of the molded keys overlies a pair of contacts. When a key is pressed while the keyboard is in this second position, an electrical circuit is formed by the key and the contacts, indicating to the computer both that a key has been pressed and which key has been pressed.