Optical-Chopper Timing

Calculate optical-chopper frequency, duty cycle, and open time.

Description

Chopper timing relates slot count and rotation speed to chopping frequency.

Chopper timing relates slot count and rotation speed to chopping frequency. The supplied open angle is used directly as a fraction of 360 degrees.^[1]

Calculate optical-chopper frequency, duty cycle, and open time.

When to use Optical-Chopper Timing

Use this tool to calculate optical-chopper frequency, duty cycle, and open time.

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 Optical-Chopper Timing 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 slotCount, rotationRpm, openAngleDegrees using the field table and calculation rules, then run the tool.
Read chopFrequencyHertz, dutyCyclePercent, openTimeSeconds. 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
slotCount	Chopper slot count	integer; minimum: 1	Required
rotationRpm	Rotation speed (rpm)	number; minimum: 0	Required
openAngleDegrees	Open angle per slot (°)	number; minimum: 0; maximum: 360	Required

Enter positive integer slots, nonnegative rpm and open angle 0–360°. Return frequency, percentage duty and open time. Zero rpm returns zero open-time placeholder.

frequency=slots×rpm/60; duty%=100angle/360; openTime=duty/frequency

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
chopFrequencyHertz	Chop frequency (Hz)	number; minimum: 0
dutyCyclePercent	Open duty cycle (%)	number; minimum: 0; maximum: 100
openTimeSeconds	Open time per cycle (s)	number; minimum: 0

json

{
  "input": {
    "slotCount": 10,
    "rotationRpm": 600,
    "openAngleDegrees": 180
  },
  "output": {
    "chopFrequencyHertz": 100,
    "dutyCyclePercent": 50,
    "openTimeSeconds": 0.005
  }
}

Limitations and assumptions

The angle is not multiplied by slot count; supply the convention intended by this model. No actual wheel geometry or blade transit is evaluated.

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 Harmonic Mode-Locking Rate: Calculate harmonic mode-locking pulse rate and spacing. For a complementary task, use Noise-Like Pulse Duty Factor: Calculate noise-like burst duty factor, burst energy, and in-burst average power.

References

Optical-Chopper Timing — tool.io

Similar or alternative tools

Harmonic Mode-Locking Rate
Calculate harmonic mode-locking pulse rate and spacing.
Noise-Like Pulse Duty Factor
Calculate noise-like burst duty factor, burst energy, and in-burst average power.