Abstract: The present invention is directed to a self-calibrating clock synchronization system that receives a periodic, digital clock signal as a reference and generates therefrom a system clock signal that dynamically tracks and is synchronized to the reference clock. The invention utilizes state machine controlled selection circuitry that comprises a plurality of predetermined delays tapped to produce a number of phase-related clock signals, and multiplexing circuitry, for selecting one of the plurality of clock signals as the system clock. A comparator compares the selected clock signal and the reference clock to determine which leads or lags the other. In response to the comparison, selection, from the plurality of clock signals, of a system clock that most clearly matches the reference signal is made.

Abstract: Encoding and decoding circuits are described for functioning as both a time and voltage based transmission system. Multiple binary inputs can be transmitted and received on a single I/O pin by encoder and decoder circuits using high speed emitter coupled-like logic.

Abstract: Encoding and decoding circuits, utilizing high speed ECL-like logic, simultaneously transmit and receive multiple binary signals via a single I/O pin.

Abstract: The present invention provides an integrated circuit that has both driver and receiver functions. The circuit of the present invention has two interrelated parts. The first part of the circuit converts true TTL signals to true ECL signals. The second part of the circuit accepts true ECL signals and drives a tri-state true TTL bus. The novel design of the present invention provides a common circuit that acts as an input reference for the circuit that converts true TTL signals to true ECL signals and as a tri-state clamp for the circuit that accepts true ECL signals and drives a tri-state true TTL bus. Using the same circuit components to perform functions in two separate circuits reduces the component count of the resulting circuit and increases the circuit's power/device count figure of merit.

Abstract: The present invention provdes a circuit for driving a TTL bus from an ECL circuit. The circuit of the present invention speeds up the "tri-state" to "active" transition by eliminating the need to pass the tri-state signal through a translator and buffer. A tri-state control circuit accepts true ECL input directly, thus eliminating the delay, power and density "cost" of the translator and buffer circuits. This circuit further improves the delay performance of tri-state/active transitions by restricting device saturation to low levels.

Abstract: The present invention provides a high speed low power electrical circuit for converting true TTL level signals to true ECL level signals. The circuit only has a single buffer delay with some small additional delay due to an input emitter follower stage. The circuit includes a clamped, switched emitter follower which acts as a level shifting comparator; a self-centering reference threshold translator; a clamped level shifted input translator; and, an ECL Buffer Driver. The circuit also includes a TTL reference and an ECL reference which are tied together. If the TTL reference level shifts slightly due to temperature changes, supply voltage shifts or other factors, the ECL voltage reference will automatically shift by an appropriate percentage to compensate for the original shift in the TTL reference.

Abstract: An improved EFL gate which provides concurrent true and complementary outputs. An input transistor has its base coupled to an input and its emitter coupled to an emitter of a reference transistor. The reference transistor has its base coupled to a voltage reference and its collector coupled to the base of a true output transistor. The emitter of the true output transistor provides the true output, while its collector is coupled to a voltage supply. A complementary output transistor has its base coupled to the collector of the input transistor with its emitter providing the complementary output. Its collector is coupled to the voltage supply, as is the collector of the input transistor.

Abstract: A high speed error correcting random access memory system includes a circuit for generation of a plurality of parity bits from a predetermined combination of data bits of a data word being stored in a random access memory such that these parity bits are stored in memory along with said data bits, and for outputting the data word from said memory system, including correcting for any single bit error in the data word, by a circuit that generates a check word from the data word bits and parity word bits stored in the memory, whose state indicates if any of the data bits are in error, and, if so, proceeds to correct any such erroneous bit. The system also includes a circuit for inserting an erroneous bit of data in memory after the parity bits have been generated, to check operation of the check word generating and output data word correction circuit. The operation of the check word generating circuit can also be suspended so as to enable uncorrected data words to be output by the memory system.

Abstract: Apparatus for transporting elongated sample holders in a sample holder storage compartment past an operating station at which sample tubes contained in the sample holders may be removed and then returned to the sample holders. First and second parallel conveyors on opposite sides of the operating station drive the holders toward and away from the operating station. Lateral drive means engage the holders in longitudinal stop positions at opposite ends of the conveyors and drive them laterally between the conveyors to lateral stop positions, one of the holders during lateral movement being driven into and away from an operative position at the operating station. Encoded label means are displayed on each sample holder for indicating the incremental spacing between the sample tubes carried in the sample holder.