Description:
|
Adjusts the stroke so that the output power of each sample is the same (i.e.
flattens the stroke). The target output power is calculated from the specified
sensitivity (in uJ/cm2). The following NVS parameters are relevant to stroke
flattening:
- stroke_tolerance - Tolerance of the calibration in percent (set media 1 stol).
Each sample is adjusted until its output power is within this tolerance.
- tolerance_limit - If the stroke cannot be flattened to stroke_tolerance, the
tolerance is automatically increased until it reaches the tolerance limit
specified here (set media 1 ltol).
- profile_bit_inc - Number of pixels between samples (set dpe pbi).
- profile_bit_width - Number of pixels in a sample's spot (set dpe pbw).
Before performing this command, the Data AOM calibration must be valid (refer to
daom command). The stroke calibration algorithm works in the following way:
- Iteration 1: The power of each sample (at half maximum) is measured and
compared to the target power, and a new DAC value is calculated by finding the
target power on the DAOM calibration curve.
- Iteration 2: The power is measured again and a new DAC value is calculated as
above, if the power is not within tolerance.
- Iteration 3: For those samples still not within tolerance, the power is
measured again and new DAC values are calculated using the slope of the DAOM
calibration curve at the current output power.
- Iterations 4 - 5: Iteration 3 is repeated, if necessary.
- Iterations 6 - 10: For those samples still not within tolerance, the Data DAC
is either incremented or decremented by one.
- If any sample is still not within tolerance at the end of iteration 10, the
tolerance is increased and the algorithm is repeated from iteration 1. This
begins a new “pass”. The tolerance during a pass is the stroke_tolerance value
times the pass number. New passes will be attempted until all samples are within
tolerance or the tolerance reaches the tolerance_limit.
|