Method and apparatus for measuring the time difference between two sampling times
AssigneeWilli Studer AG
InventorsGuy W. W. McNally, Roger Lagadec, Daniele P. C. Pelloni
Life of this patent
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Abstract
Equidistant timing pulses are counted during the time between the arrival of a first pulse edge of a first signal sequence and the arrival of a following second pulse edge of another signal sequence and are averaged to a mean value with equidistant timing pulses of an immediately preceding count between two pulse edges of the two signal sequences. The continuously formed mean values are accumulated with mean values of preceding cycles and in each case the least significant bit is further processed.
Claims22
A method for measuring the time difference between sampling points of two sampled signals comprising the steps of
- generating a sequence of equally spaced clock pulses,
- counting said equally spaced clock pulses between the arrivals of first pulse edges in the first signal and the arrival of second pulse edges in the second signal,
- averaging the number of clock pulses counted during the periods between two successive arrivals to give the actual mean value of a control cycle, and
- accumulating the actual mean values of control cycles.
An apparatus for measuring the time difference between sampling points of two sampled signals comprising
- reversing switch means for receiving the two signals being sampled and for providing at a first output one of the signals having a frequency to be employed as a control frequency and at a second output the other signal having a frequency to be employed as a counting frequency;
- a source of clock pulses;
- counter circuit means for counting clock pulses between selected pulses of the control and counting frequency signals;
- circuit means for averaging the counts in successive counting cycles;
- and
- an accumulator circuit for storing the results of the averaging.
A method for measuring the time difference between pulse edges of a first and second signal, each composed of a sequence of pulses, comprising the steps of
- providing a sequence of equally spaced clock pulses, said clock pulses having a frequency which is substantially higher than the frequency of the pulse edges of said first and second signal and which is derived from the frequency of the pulse edges of the first signal,
- counting clock pulses between the arrivals of successive pulse edges of the second signal, said successive pulse edges defining a period,
- averaging the number of clock pulses counted during a plurality of periods to give an actual mean value,
- accumulating two successive actual means values, and
- subtracting an overflow from the accumulated actual mean values.
An apparatus for measuring the time difference between pulse edges of a first and a second signal composed of sequences of pulses comprising
- reversing switch means for receiving the first and the second signal,
- said reversing switch means comprising a first output for one of the signals and a second output for the other signal,
- a source of clock pulses,
- counter circuit means for counting clock pulses between pulse edges of the first or the second signal,
- circuit means for computing mean values of counted clock pulses from a plurality of counted clock pulses, and
- an accumulator circuit for accumulating computed mean values.
Dependencies are inferred from the claim text.