Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Round-trip delay (s)

Required number input.

Fiber group index

Required number input.

Convert optical time-domain reflectometer round-trip delay to one-way fiber distance using its group refractive index. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

One-way fiber distance (m)

The resulting one-way fiber distance returned as a number.

• OTDR distance and resolution depend on group index, pulse width, sampling, dynamic range, dead zones, wavelength, launch conditions, backscatter, and event thresholds. Trace interpretation and acceptance require the fiber specification and calibrated instrument settings.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• OTDR Resolution

  Estimate OTDR two-point spatial resolution from transmitted pulse duration and fiber group index; receiver bandwidth and dead zones can worsen it.

• Sonar Range Meters

  Convert a measured two-way echo travel time into distance as rangeMeters = soundSpeedMsPerS * twoWayTravelSeconds / 2, defaulting to 1480 m/s in water.

• Ultrasonic Distance From Time

  Calculate ultrasonic pulse-echo target distance from round-trip travel time and assumed sound speed; sound speed must reflect the measurement medium.