Drive circuitry with error detection
AssigneeGTE Sylvania Incorporated
InventorAlbert H. Ashley
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Abstract
Apparatus is disclosed for sensing and determining whether or not exactly a predetermined proper number (N) of lines, part of a larger number of lines (M) are being driven, i.e., an "N of M Detector." It includes resistances connected to each of the lines, and connected together at a common summing point juncture, whose voltage is proportional to the number of lines being driven. The summing point is sensed by two comparators ("greater than" and "less than") followed by Exclusive Or logic which can deliver a "Not Exactly N" error signal. Also disclosed therewith is a transistor crosspoint switching array circuit.
Claims7
Apparatus for transmitting signals along a plurality of paths and for determining whether or not signals are being transmitted on a predetermined number of the paths, said apparatus including in combination
- a plurality of signal paths;
- a resistance network comprising an equal plurality of resistances, each resistance having one end connected to a different one of said signal paths and the other end connected to a common juncture, the voltage level produced at the common juncture being proportional to the number of signal paths having signals present thereon;
- first detecting means coupled to said common juncture and operable to produce a first indication in response to a voltage level at said common juncture produced by a predetermined number (N) or more signal paths having signals present thereon during a detection period, and operable to produce a second indication in response to a voltage level at said common juncture produced by less than the predetermined number (N) of signal paths having signals present thereon during a detection period;
- second detecting means coupled to said common juncture and operable to produce a first indication in response to a voltage level at said common juncture produced by less than said predetermined number plus one (N+1) signal paths having signals present thereon, and operable to produce a second indication in response to a voltage level at said common juncture produced by said predetermined number plus one (N+1) or more signal paths having signals present thereon;
- and
- output means coupled to said first and second detecting means for producing an error signal in response to a second indication from the first detecting means or from the second detecting means.
Dependencies are inferred from the claim text.