Dynamic digital time interval discriminator and method

Claim 2

A dynamic digital time interval discriminator for indicating the occurrence of a predetermined separation time between pairs of pulses in a sequence of pulses, which sequence is changing in repetition rate, the discriminator comprising: (a) first counting means having a clock input terminal adapted to receive a first clock signal at a first predetermined frequency, said first counting means having a reset input terminal adapted to receive the sequence of pulses thereon and a plurality of output terminals; (b) second counting means having a clock input terminal adapted to receive a second clock signal at a second predetermined frequency substantially different than said first predetermined frequency, said second counting means having an enable input terminal adapted to receive an enable signal thereon and a plurality of output terminals; (c) comparator means having a first plurality of input terminals coupled to the output terminals of said first counting means, a second plurality of input terminals coupled to the output terminals of said second counting means, and an output terminal for comparing signals at the outputs of said first and second counting means and providing an output signal when the signals compare; and (d) output means having an input terminal coupled to the output terminal of said comparator means, a reset terminal coupled to the reset terminal of said first counting means, and an output for providing a signal indicative of the occurrence of the predetermined time.

Claim 3

A dynamic digital time interval discriminator as claimed in claim 1 including in addition first and second clock signal generating means connected to the clock input terminals of the first and second counting means, respectively.

Claim 4

A dynamic digital time interval discriminator as claimed in claim 1 wherein the output means is a one bit memory.

Claim 5

A dynamic digital time interval discriminator as claimed in claim 1 including in addition Doppler radar means connected to the reset input terminal of the first counting means for providing a sequence of Doppler pulses thereto.

Claim 6

A dynamic digital time interval discriminator for indicating the occurrence of a predetermined separation time between pairs of pulses in a sequence of pulses, which sequence is decreasing in repetition rate, the discriminator comprising: (a) first counting means having a clock input terminal, a reset input terminal and a plurality of output terminals; (b) second counting means having a clock input terminal, an enable signal input terminal and a plurality of output terminals; (c) Doppler radar means having an output connected to the reset input of said first counting means for providing a sequence of Doppler pulses thereon; (d) first signal generating means connected to the clock input terminal of said first counting means for providing a first clock signal at a first predetermined frequency relatively high compared to the sequence of Doppler pulses; (e) second signal generating means connected to the clock input terminal of said second counting means for providing a second clock signal at a second predetermined frequency substantially lower than said first predetermined frequency; (f) enable signal generating means connected to the enable signal input terminal of said second counting means for supplying an enable signal thereto; (g) comparator means having a first plurality of input terminals connected to the output terminals of said first counting means, a second plurality of input terminals connected to the output terminals of said second counting means, and an output terminal for comparing signals at the outputs of said first and second counting means and providing an output signal when the signals compare; and (h) output means having an input terminal connected to the output terminal of said comparator means, a reset terminal coupled to the reset terminal of said first counting means, and an output for providing a signal indicative of the occurrence of the predetermined time.

Claim 7

A dynamic digital time interval discriminator for indicating the occurrence of a predetermined separation time between pairs of pulses in a sequence of pulses, which sequence is decreasing in repetition rate, the discriminator comprising: (a) first counting means having a clock input terminal, a reset input terminal and a plurality of output terminals; (b) second counting means having a clock input terminal, an enable signal input terminal and a plurality of output terminals; (c) Doppler radar means having an output connected to the reset input of said first counting means for providing a sequence of Doppler pulses thereon; (d) first signal generating means connected to the clock input terminal of said first counting means for providing a first clock signal at a first predetermined frequency relatively high compared to the sequence of Doppler pulses; (e) second signal generating means connected to the clock input terminal of said second counting means for providing a second clock signal at a second predetermined frequency substantially lower than said first predetermined frequency; (f) enable signal generating means connected to the enable signal input terminal of said second counting means for supplying an enable signal thereto; (g) comparator means having a first plurality of input terminals connected to the output terminals of said first counting means, a second plurality of input terminals connected to the output terminals of said second counting means, and an output terminal for comparing signals at the outputs of said first and second counting means and providing an output signal when the signals compare; and (h) output means having an input terminal connected to the output terminal of said comparator means, a reset terminal coupled to the reset terminal of said first counting means, and an output for providing a signal indicative of the occurrence of the predetermined time.

Claim 8

A dynamic digital time interval discriminator as claimed in claim 5 wherein the first and second predetermined frequencies are selected so that the number of cycles of the first predetermined frequency counted by the first counting means during the predetermined time must be at least equal to the total number of cycles of the second predetermined frequency counted by the second counting means between the application of an enable signal thereto and the end of the predetermined time.

Claim 9

A dynamic digital time interval discriminator as claimed in claim 5 including in addition second comparator means having a first plurality of input terminals connected to at least some of the output terminals of the first counting means, a second plurality of input terminals counnected to at least some of the output terminals of the second counting means, and an output terminal for comparing signals at the connected outputs of said first and second counting means and providing an output signal when the signals compare, second output means having an input terminal connected to the output terminal of said second comparator means, a reset terminal coupled to the reset terminal of said first counting means, and an output for providing a signal indicative of the occurrence of a second predetermined time, and logic means having two inputs connected to the outputs of the two output means, respectively, and providing an output signal in response to output signals from said output means.

Claim 10

A dynamic digital time interval discriminator as claimed in claim 7 wherein the predetermined time of the first comparator means and its associated output means is longer than the second pedetermined time of the second comparator means and its associated second output means, and the logic means is constructed to provide an output signal whenever a pair of pulses in the sequence of pulses are separated by a period of time between the first predetermined time and the second predetermined time.

Claim 11

In a sequence of pulses, which sequence is decreasing in repetition rate, a method of indicating when the separation between adjacent pulses reaches a predetermined time period, said method comprising the steps of: (a) providing a first signal at a frequency much higher than the repetition rate of the sequence of pulses; (b) providing a second signal at a frequency much lower than the frequency of the first signal; (c) counting the number of cycles in the first signal between each adjacent pair of pulses in the sequence; (d) counting the total number of cycles in the second signal from an initial time; and (e) comparing the counts to each other, each pulse of the sequence, and providing an output signal when the counts are substantially equal.

Claim 12

In a sequence of pulses, which sequence is decreasing in repetition rate, a method of indicating when the separation between adjacent pulses reaches a predetermined time period, said method comprising the steps of: (a) providing a first signal at a frequency much higher than the repetition rate of the sequence of pulses; (b) providing a second signal at a frequency much lower than the frequency of the first signal; (c) counting the number of cycles in the first signal between each adjacent pair of pulses in the sequence; (d) counting the total number of cycles in the second signal from an initial time; and (e) comparing the counts to each other, each pulse of the sequence, and providing an output signal when the counts are substantially equal.

Claim 13

A method as claimed in claim 9 including in addition the step of selecting the frequencies of the first and second signals so that the ratio of the total number of cycles of the second signal to the number of cycles of the first signal between adjacent pulses follows a preselected pattern.

Claim 14

A method as claimed in claim 9 for indicating when the separation between adjacent pulses reaches a second, different, predetermined time period including in addition the step of further comparing portions of the counts to each other, each pulse of the sequence, and providing a second output signal when the portions are substantially equal.

Claim 15

A method as claimed in claim 11 including in addition the step of monitoring the output signals of the two comparing steps to determine when the separation between two adjacent pulses occurs generally between the two predetermined time periods.