Pulse jitter measurement

Claim 1

In an apparatus for measuring the difference in intervals between pulses of a pulse train, the combination of: N+ 1 interval timers for generating N output voltages xi, xi 1...xj proportional to the duration of an input interval, where N equals a preselected number of interpulse intervals (j-i)+1; means for starting, stopping and resetting each of said interval timers in sequence in response to successive pulses of the pulse train; N+ 1 squaring circuits, each having an input x and producing an output x2, with each interval timer output connected to a corresponding squaring circuit input; a first summation circuit having xi, xi 1...xj as inputs and providing a first summed output which is the sum of the inputs; a second summation circuit having xi2, x(i 1)2...xj2 as inputs and providing a second summed output which is the sum of the inputs; circuit means for dividing each of said summed outputs by N providing first and second divided outputs; another squaring circuit for squaring said first divided output; a difference circuit having said squared first divided output and said second divided output as inputs and producing an output which is the difference of the inputs; and a square root circuit having said difference output as an input and providing an output which is the square root of the input and which is an indication of the variations in interval between N successive pulses of the pulse train.