Digital phase discriminators and video gate generators

Claim 2

A discriminator for detecting the positions of video pulse signals within a gated period and providing an electrical signal for centering the gate on the positions, comprising: means for detecting the position of the first said video pulse to occur within said gated period wherein said first pulse position detecting means includes a first binary counter coupled to the video pulse input; means for detecting the position of the last said video pulse to occur within said gated period wherein said last pulse position detecting means includes a second binary counter coupled to a clock pulse, and a binary register coupled to said second binary counter and the video pulse input; and means for comparing said detected positions and modifying said gated period such that the positions are equally spaced about the center of said period wherein said comparing and modifying means includes a digital to analog converter coupled to said binary register and said first binary counter for comparing the outputs of the binary register and the first binary counter and providing an electrical signal in response to the comparison for modifying the gated period.

Claim 3

The discriminator of claim 1, further comprising: means for generating a gate signal and a composite vertical and horizontal crosshair signal including said second binary counter wherein the gate signal and a remotely generated second gate signal and crosshair signal are combined to form the composite crosshair output for use in a guidance system.

Claim 4

The discriminator of claim 2 wherein said sequencing circuit includes a shift counter.

Claim 5

The discriminator of claim 2 wherein said sequencing circuit includes a tapped delay line.

Claim 6

The discriminator of claim 2 wherein said sequencing circuit includes a cascade of one-shot multivibrators.

Claim 7

The discriminator of claim 2, further comprising: means for generating a gate signal and a crosshair signal including said sequencing circuit.

Claim 8

A discriminator for detecting the positions of video pulse signals within a gated period and providing an electrical signal for centering the gate on the positions, comprising: means for detecting the position of the first said video pulse to occur within said gated period; means for detecting the position of the last said video pulse to occur within said gated period; means for comparing said detected positions and modifying said gated period such that the positions are equally spaced about the center of said period; wherein said first and last pulse position detecting means include a sequencing circuit for providing enabling pulse outputs sequentially at a predetermined rate wherein each pulse output corresponds to an interval within the gated period and electronic circuitry coupled to the sequencing circuit for each interval within the gated period such that the circuitry associated with the interval of occurrence of the first and the last video pulse provides an electric signal output, and said comparing and modifying means includes a digital to analog converter coupled to the output of said circuitry associated with the interval of occurrence of the first video pulse and the output of said circuitry associated with the interval of occurrence of the last video pulse within the gate for comparing said interval circuitry outputs and providing an electrical signal in response to the comparison for modifying the gated period.

Claim 9

A discriminator for detecting the positions of video pulse signals within a gated period and providing an electrical signal for centering the gate on the positions, comprising: means for detecting the position of the first said video pulse to occur within said gated period; means for detecting the position of the last said video pulse to occur within said gated period; means for comparing said detected positions and modifying said gated period such that the positions are equally spaced about the center of said period; wherein said first and last pulse position detecting means include a sequencing circuit for providing enabling pulse outputs sequentially at a predetermined rate wherein each pulse output corresponds to an interval within the gated period and electronic circuitry coupled to the sequencing circuit for each interval within the gated period such that the circuitry associated with the interval of occurrence of the first and the last video pulse provides an electric signal output, and said comparing and modifying means includes a digital to analog converter coupled to the output of said circuitry associated with the interval of occurrence of the first video pulse and the output of said circuitry associated with the interval of occurrence of the last video pulse within the gate for comparing said interval circuitry outputs and providing an electrical signal in response to the comparison for modifying the gated period.