Abstract Two one-shot circuits are triggered by an input data pulse to be interrogated. At the leading edge of the input pulse, one of the two one-shot circuits generates a pulse of the specified width minus the specified tolerance. The other one-shot circuit generates a pulse width equal to the specified tolerance at the trailing edge of the interrogated pulse. The output of the first one-shot circuit triggers a third one-shot circuit which in turn generates a pulse of a width equal to twice the specified tolerance. The outputs of the second and third one-shot circuits are combined in a NAND gate which generates the detection pulse to indicate that the interrogated pulse is within the specified tolerance. The detection pulse is generated as soon as the trailing edge of the interrogated pulse is received. Thus, two input data pulses can be placed as close together as possible as long as the individual pulse identity is maintained, making it possible to maximize the date rate. A multiplicty of detector circuits may be connected in a parallel manner, each generating a detection pulse upon the reception of a pulse specified length, thus permitting the decoding of an entire pulse-width-coded message.
A device for detecting a pulse of a particular width falling within a specific tolerance comprising: means for generating a first pulse of a minimum acceptable width upon reception of the leading edge of an interrogated pulse; and means coupled to said means for generating a first pulse for generating a second pulse of a width equal to twice the specific tolerance; and means for generating a third pulse upon reception of the trailing edge of said interrogated pulse; means coupled to said means for generating a second pulse and to said means for generating a third pulse for determining if said third pulse is coincident with said second pulse, wherein a detection pulse is generated if said second and third pulses are coincident.
Claim 2
Independent Claim
124 words
A device for detecting a pulse of a particular width falling within a specific tolerance comprising: means for generating a first pulse of a minimum acceptable width upon reception of the leading edge of an interrogated pulse; and means coupled to said means for generating a first pulse for generating a second pulse of a width equal to twice the specific tolerance; and means for generating a third pulse upon reception of the trailing edge of said interrogated pulse; means coupled to said means for generating a second pulse and to said means for generating a third pulse for determining if said third pulse is coincident with said second pulse, wherein a detection pulse is generated if said second and third pulses are coincident.
Claim 3
Dependent Claim
34 words
The device as claimed in claim 1 wherein said means for generating a first, second, and a third pulse is each a one shot circuit capable of producing a pulse of a preset length.
Claim 4
Dependent Claim
26 words
The device as claimed in claim 1 wherein said means for determining if said third pulse is coincident with said second pulse is a NAND gate.