WMS 2f Error Signal
Resolve a wavelength-modulation 2f signal into amplitude, phase, and normalized lock error.
Description
Wavelength-modulation readout combines in-phase and quadrature second-harmonic signals.
Wavelength-modulation readout combines in-phase and quadrature second-harmonic signals. Normalized lock error uses only the in-phase component divided by DC.1
Resolve a wavelength-modulation 2f signal into amplitude, phase, and normalized lock error.
When to use WMS 2f Error Signal
Use this tool to resolve a wavelength-modulation 2f signal into amplitude, phase, and normalized lock error.
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 WMS 2f Error Signal 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 secondHarmonicInPhase, secondHarmonicQuadrature, dcSignal using the field table and calculation rules, then run the tool.
- Read secondHarmonicAmplitude, secondHarmonicPhaseRadians, normalizedErrorSignal. 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 |
|---|---|---|---|
| secondHarmonicInPhase | 2f in-phase component | number | Required |
| secondHarmonicQuadrature | 2f quadrature component | number | Required |
| dcSignal | DC absorption signal | number | Required |
Enter finite components and nonzero signed DC reference. Return amplitude, phase in radians and signed normalized error.
amplitude=hypot(I,Q); phase=atan2(Q,I); error=I/DC Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| secondHarmonicAmplitude | 2f amplitude | number; minimum: 0 |
| secondHarmonicPhaseRadians | 2f phase (rad) | number |
| normalizedErrorSignal | DC-normalized 2f error signal | number |
{
"input": {
"secondHarmonicInPhase": 3,
"secondHarmonicQuadrature": 4,
"dcSignal": 10
},
"output": {
"secondHarmonicAmplitude": 5,
"secondHarmonicPhaseRadians": 0.9272952180016122,
"normalizedErrorSignal": 0.3
}
}Limitations and assumptions
No demodulation, concentration calibration or feedback loop is executed. Zero components give the runtime atan2 convention.
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 Optogalvanic Modulation Contrast: Calculate optogalvanic modulation amplitude and normalized contrast. For a complementary task, use Wavelength-Lock Selector: Select an absorption-cell, etalon, or hybrid wavelength lock from supplied requirements.
References
-
WMS 2f Error Signal — tool.io
Similar or alternative tools
- Optogalvanic Modulation Contrast
Calculate optogalvanic modulation amplitude and normalized contrast.
- Wavelength-Lock Selector
Select an absorption-cell, etalon, or hybrid wavelength lock from supplied requirements.