At&t Bell Laboratories

International Business Machines Corporation

Lockheed Martin Corporation

Hubert A Miller

Donald E Wallis

Michael J Buehler

Wendell P Marple

Michael A Sweeney

Kathleen F Bonaffini

Andrew M Bonaffini

Galen Plunkett, Jr

Sidney F Rudolph

A high performance, real-time control sequencer is disclosed which incorporates a unique state matrix logic. This real-time control sequencer performs rapid resolution of control processed state transitions and the required control actions as a function of detected external events and the current control process state. The control sequencer's micro-instructions present event and current state data as inputs to a state matrix logic and initiate state matrix operations. The state matrix, in turn, outputs data defining and initiating the next control process state, required process control actions to be performed by the control sequencer microcode, process status, and event response or control output data. The real-time, event-driven data processor invention provides greater flexibility for reconfiguring event patterns to be detected and responses desired. It provides for a faster resolution of control process state transitions and the required control actions, and it accomplishes this with a larger repertoire of event patterns and responses stored in a smaller memory area, than has been required in the prior art.

Real-time control sequencer with state matrix logic

A current pulse signal, which is generated by an optical detector, is fed to an input of an edge detector circuit. The current pulse signal is converted into a differentiated voltage pulse signal having a negative going pulse corresponding to a positive going slope of the input signal and a positive going pulse corresponding to the negative going slope of the input waveform. The positive differentiated pulse has a rise amplitude which is larger than its fall amplitude so that its most positive down level has a relatively positive absolute voltage value. Correspondingly, the negative differentiated pulse has a fall amplitude which is greater than its rising amplitude so that its most negative up level is more negative in absolute value than a nominal median zero voltage reference level. The output of the edge detection circuit is connected to a dual threshold comparator having a positive threshold for detecting valid positive differentiated pulses and a negative threshold for detecting valid negative differentiated pulses. Noise components on them most positive down level of the positive differentiated pulse and the most negative up level of the negative differentiated pulse are less likely to exceed the positive and the negative threshold values, respectively, of the comparator. Therefore, the likelihood that a reliable detection of valid positive and negative pulses is enhanced as well as enhancing the noise immunity for background noise in high speed, small amplitude current pulse applications.

Edge detection using dual trans-impedance amplifier

A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks. Microprocessor-based circuitry is utilized for numerous system tasks such as signal generation, digital signal processing and controlling sensitive analog measurements. Signal generation includes digital generation of analog waveforms. Signal processing techniques incorporate various digital filters to analyze sample sequences derived from, for example, dial pulses and coin telephone signals. Sensitive analog measurements of loop characteristics are effected with a magnetic current detector that operates over broad current and frequency ranges. Frequency dependent measurements are converted to DC using synchronous demodulation techniques to enhance resolution.

Coin telephone measurement circuitry

A method for analysis of rotary dial pulses focuses on transitions between pulse levels and differentiates true level changes from noise using a procedure employing two sample counters. One counter registers the number of consecutive samples at either the high or low levels and, once a predetermined number of consecutive samples are detected, a corresponding high or low level is declared. However, since noise may influence the detection, the total number of samples, from the first indication of a level change until the declaration of a state, is maintained in a second counter. A false transition reinitializes both counters, while level changes yielding less than the predetermined number only reinitialize the first counter.

Dial pulse measurement circuitry

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Manassas, VA, United States of America

Hubert A Miller