Swept-Frequency Distance
Convert swept-frequency phase slope to delay and one-way distance.
Description
Swept-frequency ranging relates unwrapped phase slope to a round-trip delay.
Swept-frequency ranging relates unwrapped phase slope to a round-trip delay. One-way distance uses half the corresponding vacuum path.1
Convert swept-frequency phase slope to delay and one-way distance.
When to use Swept-Frequency Distance
Use this tool to convert swept-frequency phase slope to delay and one-way distance.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use Swept-Frequency Distance and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter phaseSlopeRadiansPerHertz using the field table and calculation rules, then run the tool.
- Read roundTripDelaySeconds, distanceMeters. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| phaseSlopeRadiansPerHertz | Measured phase slope (rad/Hz) | number | Required |
Enter finite signed phase slope in radians/Hz. Return signed delay and meters using c=299792458 m/s.
delay=slope/(2π); distance=c delay/2 Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| roundTripDelaySeconds | Round-trip delay (s) | number |
| distanceMeters | One-way distance (m) | number |
{
"input": {
"phaseSlopeRadiansPerHertz": 6.283185307179586e-9
},
"output": {
"roundTripDelaySeconds": 1e-9,
"distanceMeters": 0.14989622900000002
}
}Limitations and assumptions
No phase fitting, offset removal or refractive-index correction is included.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use FMCW Lidar Range and Velocity: Calculate ideal FMCW lidar range and radial velocity from separated beat frequencies. For a complementary task, use Synthetic Wavelength: Calculate the two-color synthetic wavelength for interferometric unwrapping.
References
-
Swept-Frequency Distance — tool.io
Similar or alternative tools
- FMCW Lidar Range and Velocity
Calculate ideal FMCW lidar range and radial velocity from separated beat frequencies.
- Synthetic Wavelength
Calculate the two-color synthetic wavelength for interferometric unwrapping.