Laser measurement system with digital delay compensation

A method of computing time difference between a measured signal and a reference signal, the method comprising:

• measuring a first cycle of the measured signal to arrive at a first denominator;
• calculating a time after the first cycle of the measured signal and a subsequent pulse of a reference clock signal to arrive at a first numerator;
• calculating a time after the first cycle of the reference signal and the subsequent pulse of the reference clock signal to arrive at a second numerator;
• and
• deriving a difference between the first and second numerators to arrive at a first time difference value.

A method of computing phase difference between a measured signal and a reference signal, the method comprising:

• receiving the measured signal from a first receiver wherein the measured signal provides a pulse on each cycle;
• generating a reference clock signal and a measurement clock signal;
• receiving the reference signal from a second receiver wherein the reference signal provides a pulse on each cycle;
• calculating a measurement denominator value based on a first pulse and a succeeding second pulse of the measured signal wherein the value is calculated against the measurement clock signal;
• calculating a measurement numerator value based on the second pulse of the measured signal and a next succeeding pulse of the reference clock signal;
• deriving a measurement quotient value by dividing the measurement numerator value by the measurement denominator value;
• calculating a reference denominator value based on a first pulse and a succeeding second pulse of the reference signal wherein the value is calculated against the measurement clock signal;
• calculating a reference numerator value based on the second pulse of the reference signal and a next succeeding pulse of the reference clock signal;
• deriving a reference quotient value by dividing the reference numerator value by the reference denominator value;
• and
• calculating a difference between the measurement quotient value and the reference quotient value to arrive at a position value, wherein the position value relates a phase difference.

A method of computing time difference between a measured signal and a reference signal, the method comprising:

• receiving the measured signal from a first receiver wherein the measured signal provides a pulse on each cycle;
• generating a reference clock signal and a measurement clock signal;
• receiving the reference signal from a second receiver wherein the reference signal provides a pulse on each cycle;
• calculating a measurement denominator value based on a first pulse and a succeeding second pulse of the measured signal wherein the value is calculated against the measurement clock signal;
• calculating a measurement numerator value based on the second pulse of the measured signal and a next succeeding pulse of the reference clock signal;
• deriving a measurement quotient value by dividing the measurement numerator value by the measurement denominator value;
• calculating a reference numerator value based on the second pulse of the reference signal and a next succeeding pulse of the reference clock signal;
• calculating a difference between the measurement numerator value and the reference numerator value to arrive at a time difference value.

An optical measurement system comprised of:

• an optical receiver outputting a measured signal having a clock cycle;
• a reference receiver outputting a reference signal having a clock cycle;
• a system clock signal;
• and
• a measurement clock signal, wherein
• the clock cycle of the measured signal and the clock cycle reference are calculated against the measurement clock signal,
• the beginning of the second cycle of the measured signal is timed to a next subsequent pulse of the system clock signal and divided by the clock cycle of the measured signal to arrive at a first vector phase value;
• the beginning of the second cycle of the reference signal is timed to the next subsequent pulse of the system clock signal and divided by the clock cycle of the reference signal to arrive at a second vector phase value;
• and
• the difference between the first and the second vector phase values is calculated to arrive at a first position value.

An optical measurement system comprised of:

• an optical receiver outputting a measured signal having a clock cycle;
• a reference receiver outputting a reference signal having a clock cycle;
• a system clock signal;
• and
• a measurement clock signal, wherein
• the clock cycle of the measured signal and the clock cycle reference are calculated against the measurement clock signal,
• the beginning of the second cycle of the measured signal is timed to a next subsequent pulse of the system clock signal to arrive at a first time value and
• divided by the clock cycle of the measured signal to arrive at a vector phase value;
• the beginning of the second cycle of the reference signal is timed to the next subsequent pulse of the system clock signal to arrive at a second time value;
• and
• the difference between the first and the second time values is calculated to arrive at a time difference value.