Pulse width discrimination

Claim 2

Pulse width discriminator for processing input pulses, each having a leading edge and a trailing edge, in accordance with the pulse width of said input pulses, comprising, in combination, first circuit means operative a predetermined time interval after the start of an input pulse for furnishing a first pulse having a first pulse width corresponding to the width of said input pulse following said predetermined time interval, whereby a first pulse is furnished only when the width of an input pulse exceeds said predetermined time interval; and second circuit means for extending the width of said First pulse, when present, by a time interval corresponding to said predetermined time interval, said so extended first pulses constituting output pulses, whereby an output pulse of corresponding width is furnished for each input pulse exceeding a predetermined width.

Claim 3

A pulse width discriminator as set forth in claim 1, wherein said first circuit means comprise first signal furnishing means responsive to the leading edge of an input signal for furnishing a first signal varying substantially linearly with respect to time during the presence of the corresponding input pulse; first threshold means for furnishing a first threshold signal corresponding to said first signal after said first signal has exceeded a predetermined threshold vaLue; and pulse shaping means for furnishing said first pulses in response to said first threshold signal.

Claim 4

A pulse width discriminator as set forth in claim 1, wherein said second circuit means comprise second signal furnishing means for furnishing a second signal comprising a reference level signal in the presence of a first pulse, and an additional signal, starting at said reference level and varying linearly with respect to time upon cessation of said first pulse; second threshold means having a threshold level spaced from said reference level in the direction of variation of said additional signal in accordance with the time rate of variation of said additional signal and said predetermined time interval, said second threshold means thus furnishing a second threshold signal constant from the start of said first pulse until said additional signal exceeds said threshold level; and second pulse-shaping means for shaping the constant portion of said second threshold signal into a substantially rectangular output pulse.

Claim 5

A pulse discriminator as set forth in claim 2, wherein said first signal furnishing means comprise a capacitor; a power source for charging said capacitor; and normally closed switching means connected in parallel to said capacitor and adapted to open upon receipt of an input pulse and to stay open for the duration of said input pulse.

Claim 6

A pulse width discriminator as set forth in claim 3, wherein said second signal furnishing means comprise a second capacitor; normally open switching means connected in parallel to said second capacitor, and adapted to close in response to said first pulses and remain closed for the duration of each of said first pulses.

Claim 7

A pulse width discriminator as set forth in claim 2 wherein said pulse shaping means comprise a Schmitt trigger circuit.

Claim 8

A pulse width discriminator as set forth in claim 3, wherein said second pulse shaping means comprise a Schmitt trigger circuit.

Claim 9

A pulse width discriminator as set forth in claim 1, wherein said input pulses are derived from video signals by further threshold means.