Abstract:
The encoding circuits of this invention provide signals for representing binary data in a storage medium or in a transmission system as a waveform that has a small constrained value of accumulated difference between its positive and negative portions. The waveform has minimum and maximum run lengths between transitions between positive and negative values so that it provides both high density and good clocking. Several new codes are described which can be implemented with fewer logic and storage components than prior codes of this general type.
Abstract:
PROBLEM TO BE SOLVED: To provide an integrated circuit (IC) including at least one combined logic circuit. SOLUTION: The combined logic circuit includes two types of logic block cells for mutually correcting the influence caused by manufacturing parameters which affect cell transistors. The two types of cells can be made as a condensed cell, having FET gates with a contact pitch and a separated cell, having FET gates with a pitch wider than the contact pitch. Variations in the delay of the condensed cell caused by the FET gates being printed, while being out of focus, can be offset by the the variations in the delay of the separated cell. COPYRIGHT: (C)2005,JPO&NCIPI
Abstract:
This specification describes a decoder for a programmable logic array (PLA) having opposite ends of input lines of the array connected to outputs of different decoders. Previously two-bit decoders were arranged on opposite sides of the array to generate input variables from two sets of two different input signals each and feed those input variables to four input lines. Here, instead of using two-bit decoders, four one-bit decoders are positioned on each side. The outputs of these one-bit decoders are programmable to change the connections between them and the input lines of the array. The arrangement permits the decoders to perform one-bit, two-bit decoding on signals on the same side of the input lines, to do two-bit decoding on signals on opposite sides of the array and in combination with other sets of decoders to do three and four-bit decoding of input signals.
Abstract:
1475255 Selective signalling INTERNATIONAL BUSINESS MACHINES CORP 1 Oct 1975 [18 Dec 1974] 40080/75 Heading G4H A logic array with testing apparatus comprises a plurality of decoders feeding input lines of a logic-performing matrix, the matrix incorporating a check line intersecting the input lines for storing information on the number of operative logic means located along each of the input lines. In Fig. 1, input bits at 14 are decoded in pairs by decoders 12a, 12b ... 12, each decoder selecting one of a respective 4 row lines of an AND array 10. The array 10 has FETs at selected row-column intersections to provide on each column line the AND of a respective combination of the row lines. The column lines feed an OR array 24 which similarly has FETs at selected row-column intersections and feeds latches via its row lines. The AND array has an extra column line 21 specifying a parity bit for each row line according to the number of FETs which should be present in it, and the OR array has an extra row line 19 specifying a parity bit for each column line. To test the AND array, a command decoder 36 is used to enable the decoders 12a, 12b ... 12 in turn, each decoder, when enabled, being supplied with appropriate inputs to select all its outputs in turn. As each row line of the AND array is thus selected, the column outputs are loaded into a shift register 48 and parity-checked by an EXCL-OR tree 50. The OR array is then tested by decoupling the two arrays using a mask output 40 of the command decoder 36, and inserting a 1 into the shift register 48 and shifting it along thus selecting the column lines of the OR array in turn, the row outputs being parity-checked in each case by an EXCL-OR tree 54. Another output 42 of the command decoder 36 (used e.g. for normal operation) enables all the decoders 12a, 12b ... 12 and resets the shift register 48. EXCL-ORing may be done serially. Extra redundancy lines could be provided in the arrays.
Abstract:
This specification describes arrays for performing logic functions which include circuitry for testing the arrays to see if the arrays will perform the logic functions that they were designed to perform. During testing, a gating signal to each of the decoders is used to couple the interrogatior signals of one of these decoders at a time to the input lines of the array. This allows the interrogation of one input line at a time and the detection of the output signals produced by that interrogation on the output lines of the array. To determine whether the output signals are proper, the array contains one or more additional output lines which contain parity or check bits on the circuit elements arranged along each of the input lines. When an input line is interrogated the output signals including those produced by the parity or check bits are exclusively OR'd to determine if the interrogated input line contains the proper number of circuit elements. This circuitry eliminates the need for storing information as to logic functions performed by any particular array and allows a uniform testing sequence to be used in testing all the arrays.
Abstract:
1475255 Selective signalling INTERNATIONAL BUSINESS MACHINES CORP 1 Oct 1975 [18 Dec 1974] 40080/75 Heading G4H A logic array with testing apparatus comprises a plurality of decoders feeding input lines of a logic-performing matrix, the matrix incorporating a check line intersecting the input lines for storing information on the number of operative logic means located along each of the input lines. In Fig. 1, input bits at 14 are decoded in pairs by decoders 12a, 12b ... 12, each decoder selecting one of a respective 4 row lines of an AND array 10. The array 10 has FETs at selected row-column intersections to provide on each column line the AND of a respective combination of the row lines. The column lines feed an OR array 24 which similarly has FETs at selected row-column intersections and feeds latches via its row lines. The AND array has an extra column line 21 specifying a parity bit for each row line according to the number of FETs which should be present in it, and the OR array has an extra row line 19 specifying a parity bit for each column line. To test the AND array, a command decoder 36 is used to enable the decoders 12a, 12b ... 12 in turn, each decoder, when enabled, being supplied with appropriate inputs to select all its outputs in turn. As each row line of the AND array is thus selected, the column outputs are loaded into a shift register 48 and parity-checked by an EXCL-OR tree 50. The OR array is then tested by decoupling the two arrays using a mask output 40 of the command decoder 36, and inserting a 1 into the shift register 48 and shifting it along thus selecting the column lines of the OR array in turn, the row outputs being parity-checked in each case by an EXCL-OR tree 54. Another output 42 of the command decoder 36 (used e.g. for normal operation) enables all the decoders 12a, 12b ... 12 and resets the shift register 48. EXCL-ORing may be done serially. Extra redundancy lines could be provided in the arrays.