Method and means for generating a synchronizing pulse from a repetitive wave of varying frequency

Claim 1

A method of generating a trigger pulse that is synchronized with a repetitive signal exhibiting a range of frequencies and having an on period of length T 1 and an off period of length T 2 comprising the steps of: generating a first counting rectangular wave at a frequency greater than the frequency of the repetitive signal; generating a second counting rectangular wave at a frequency that is greater than the frequency of the repetitive signal and at least equal to the product of the ratio of the on period to the off period times the frequency of the first counting rectangular wave; counting the cycles of the first counting wave during the period T 1 to obtain a first count; counting the cycles of the second counting wave after the end of the period T 1 to obtain a second count; comparing the first count to the second count; and generating a trigger pulse when the first count equals the second count, which trigger pulse is synchronized with the repetitive signal.

Claim 2

A method of generating a trigger pulse that is synchronized with a repetitive signal exhibiting a range of frequencies and having an on period of length T 1 and an off period of length T 2 comprising the steps of: generating a first counting rectangular wave at a frequency greater than the frequency of the repetitive signal; generating a second counting rectangular wave at a frequency that is greater than the frequency of the repetitive signal and at least equal to the product of the ratio of the on period to the off period times the frequency of the first counting rectangular wave; counting the cycles of the first counting wave during the period T 1 to obtain a first count; counting the cycles of the second counting wave after the end of the period T 1 to obtain a second count; comparing the first count to the second count; and generating a trigger pulse when the first count equals the second count, which trigger pulse is synchronized with the repetitive signal.

Claim 4

An apparatus for generating a trigger pulse that is synchronized to the rectangular synchronizing signal from a high-speed framing camera over a range of speeds of said high-speed framing camera, said signal having a first portion and a second portion, said apparatus comprising: a first oscillator; a second oscillator; a first counter connected to said first oscillator and responsive thereto to count cycles thereof during a first portion of said rectangular synchronizing signal; a second counter connected to said second oscillator and responsive thereto to count cycles thereof during a second portion of said rectangular synchronizing signal; and a comparator connected to said first and second counters and generating a trigger pulse when said counts of cycles are equal, which trigger pulse is synchronized to said output synchronizing signal over a range of speeds of said camera.

Claim 5

An apparatus for generating a trigger pulse that is synchronized to the rectangular synchronizing signal from a high-speed framing camera over a range of speeds of said high-speed framing camera, said signal having a first portion and a second portion, said apparatus comprising: a first oscillator; a second oscillator; a first counter connected to said first oscillator and responsive thereto to count cycles thereof during a first portion of said rectangular synchronizing signal; a second counter connected to said second oscillator and responsive thereto to count cycles thereof during a second portion of said rectangular synchronizing signal; and a comparator connected to said first and second counters and generating a trigger pulse when said counts of cycles are equal, which trigger pulse is synchronized to said output synchronizing signal over a range of speeds of said camera.

Claim 7

An apparatus for generating a pulse synchronized to and timed to a predetermined region of a rectangular wave having an on time and an off time over a range of frequencies comprising a first flip-flop receiving said rectangular wave as an input and generating a shaped rectangular wave in response thereto; a second flip-flop coupled to said first flip-flop and responsive to said shaped rectangular wave to generate a further shaped rectangular wave in response thereto; a first oscillator generating a first counting signal at a predetermined frequency; a first NAND gate connected to said second flip-flop and said first oscillator and responsive to outputs therefrom to provide a first counting signal; a first counter connected to said first NAND gate and responsive to said first counting signal to generate a count of cycles of said first oscillator; a preset constant circuit connected to said first counter to provide as an input a predetermined initial value thereon; a third flip-flop connected to said second flip-flop and responsive to a 0 output therefrom; a second oscillator generating a second counting signal at a frequency that is related to the frequency of said first oscillator by a multiplicative factor equal to the ratio of on time to off time of said rectangular wave; a first AND gate connected to the 0 output terminal of said second flip-flop and to said 1 output terminal of said first flip-flop and generating an output in response thereto; an EXCLUSIVE-OR gate connected to the output of said first AND gate and the 0 output of said third third flip-flop at the start of the off time of said rectangular wave; a second NAND gate connected to said second oscillator and said third flip-flop to provide a second counting signal; a second counter connected to said second NAND gate and responsive to said second counting signal to generate a count of cycles of said second oscillator; a comparator connected to said first and second counters and responsive thereto to generate an output signal when said counts of said first and second counters are equal; an inverter connected to said comparator to invert the output signal thereof; a fourth flip-flop connected to said inverter and responsive thereto to generate an output pulse, which pulse is synchronized to and timed to said predetermined region of said rectangular wave.

Claim 8

An apparatus for generating a pulse synchronized to and timed to a predetermined region of a rectangular wave having an on time and an off time over a range of frequencies comprising a first flip-flop receiving said rectangular wave as an input and generating a shaped rectangular wave in response thereto; a second flip-flop coupled to said first flip-flop and responsive to said shaped rectangular wave to generate a further shaped rectangular wave in response thereto; a first oscillator generating a first counting signal at a predetermined frequency; a first NAND gate connected to said second flip-flop and said first oscillator and responsive to outputs therefrom to provide a first counting signal; a first counter connected to said first NAND gate and responsive to said first counting signal to generate a count of cycles of said first oscillator; a preset constant circuit connected to said first counter to provide as an input a predetermined initial value thereon; a third flip-flop connected to said second flip-flop and responsive to a 0 output therefrom; a second oscillator generating a second counting signal at a frequency that is related to the frequency of said first oscillator by a multiplicative factor equal to the ratio of on time to off time of said rectangular wave; a first AND gate connected to the 0 output terminal of said second flip-flop and to said 1 output terminal of said first flip-flop and generating an output in response thereto; an EXCLUSIVE-OR gate connected to the output of said first AND gate and the 0 output of said third third flip-flop at the start of the off time of said rectangular wave; a second NAND gate connected to said second oscillator and said third flip-flop to provide a second counting signal; a second counter connected to said second NAND gate and responsive to said second counting signal to generate a count of cycles of said second oscillator; a comparator connected to said first and second counters and responsive thereto to generate an output signal when said counts of said first and second counters are equal; an inverter connected to said comparator to invert the output signal thereof; a fourth flip-flop connected to said inverter and responsive thereto to generate an output pulse, which pulse is synchronized to and timed to said predetermined region of said rectangular wave.