International Business Machines Corporation

Francis P Carrubba

Peter Anthony Franaszek

John Cocke

Paul E Stuckert

David D Grossman

Norman H Kreitzer

Walter Edgar Daniels, Jr

Hierarchical memory system including separate cache memories for storing

A Minimum Delay Module Assembly, having unrestricted accessibility for servicing, that provides substantially constant electrical and thermal environments for all portions of the assembly regardless of configuration. The assembly comprises a plurality of vertical page modules in which each page module is vertically hinged to the adjacent page module. Electrical interconnections are provided between the page modules by means of cable assemblies which enter each page module in the edge thereof adjacent said hinges. Individual self contained cooling means are provided for each page module so that the flow of air is up through the bottom of each page module and out through the top thereof. Resilient conduit means may be utilized to supply a pressurized coolant to each page module regardless of the configuration of the module assembly. The complete vertically hinged module assembly is supported on a base assembly, including a foraminous base member sufficiently large to support said hinged module assembly when in the closed position and further including at least one foraminous foldable shelf which folds out of the way when the assembly is in the closed position and folds to a position coplanar with said base member when in the 'open for service' position. The base assembly further includes a chamber or space under the base member which provides for an unrestricted flow of air up through said base member.

Minimum delay module assembly

A method of and apparatus for time compression and changing the readout speed of a delta modulation encoded audio signal. The encoded audio signal has portions selectively deleted therefrom in accordance with detected zero crossovers of the same sign which occur in a predetermined timing sequence. The encoded audio signal which has had portions selectively deleted therefrom is decoded, with the undeleted decoded portions being joined. The undeleted portions have the same gain factor where joined, thereby eliminating step transients.

High speed voice replay via digital delta modulation

In a delta modulator a sequence of code symbols are generated which are indicative of increments of signal level, with each code symbol being determined in accordance with the difference in signal level between an input signal and a prediction signal which is a representation of the input signal. A sequence of the generated code symbols are stored, including the most recent code symbol and a preceding number of code symbols, with the pattern of code symbols at any instant defining a state of signal activity. There is a table of delta increments, a table of threshold values, and a digital gain logic network, all of which provide signal outputs which are controlled by the state of signal activity represented by the stored code signal pattern. The signal output from the delta table and the threshold table are modified an amount determined by the value of the signal output from the digital gain logic network. An accumulation of modified delta increments are summed with modified threshold values for providing the prediction signal. The prediction signal and the input signal are compared for generating a new code symbol.

Gain method and apparatus for a delta modulator

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North Haven, CT, United States of America

Francis P Carrubba