Pyrocam IV Operator’s Manual Document No. 50337-001 Rev F 2/21/2017 Page 20
In pulse mode 3, the Pyrocam is receiving trigger pulses at a rate faster than the
pyroelectric detector can read out. See Figure 3.4. Thus, trigger inputs are
automatically divided down to a range that the Pyrocam can keep up with. The dividing
factor will be the least integer value that will reduce the effective rate to a value that
falls just within a rate supported in pulse mode 2.
For example, a pulse rate of 150Hz will be divided by 2, yielding a capture rate of 75Hz.
A pulse rate of 1000Hz will be divided by 9, yielding a rate of 111Hz. Note that this does
not mean that the Pyrocam will output data frames at a rate of 75 or 111Hz. The actual
frame rate output from the Pyrocam is limited by equipment bandwidths that are not
accurately predictable.
Figure 3.4 : Mode 3, High Speed,
Use Mode 2, Periodic timing.
Example: Laser pulse rate is 350Hz, Exposure 50us, Delay 0us
Solution:
3.4 Chopped (CW) Operation
The Pyrocam chopped models contain an internal chopper for use with CW lasers or to do
thermal imaging when fitted with a specialized lens. The operation of the chopper is
managed by the camera’s firmware and no external trigger is required when in chopped
mode. The chop rate can be reduced to increase responsivity, but with some loss in
response linearity.
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