Dewetron DEWE-ORION-1616-10 Series, Техническое справочное руководство

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DE-M060304E • DEWE-ORION-1616-10x • Technical Reference Manual • Printing version 1.2.0 • March 19, 2014
DEWE-ORION-1616-10x
Internal Time Base
(80MHz)
Filter Input Signal
Filter Output Signal
Gate Time Gate Time
Figure 25: Input signal with chatter
It can be chosen between eight filter settings: Off, 100 ns, 200 ns, 500 ns, 1 µs, 2 µs, 4 µs and 5 µs. Two
examples of filter settings are described.
The 100 ns filter will pass all pulse widths (high and low) that are 100 ns or longer. It will block all pulse
widths that are 75 ns or shorter. The 5 µs filter will pass all pulse widths (high and low) that are 5 µs or longer
and will block all pulse widths that are 4.975 µs or shorter.
The internal sampling clock (time base) is 80 MHz, so the period time amounts 12.5 ns. Pulse widths be-
tween gate time minus two internal time base period times may or may not pass, depending on the phase of
the input signal with respect to the internal time base.
Properties of all filter settings:
Filter settings Pulse width to pass Pulse width to be blocked
100 ns 100 ns 75 ns
200 ns 200 ns 175 ns
500 ns 500 ns 475 ns
1 µs 1 µs 975 ns
2 µs 2µs 1.975 µs
4 µs 4 µs 3.975 µs
5 µs 5 µs 4.975 µs
Off - -
Filter Gate Times
3.2.2.2 Reset on start measure
Usually all counters are reset at the start of data acquisition, i.e. the counter value is set to zero at the start
of data acquisition. In some applications this is not required. An angle encoder for example is adjusted to the
physical zero position at the beginning of a test procedure. By resetting the counter at every start of the mea-
surement this adjustment get lost. Without this reset the counter is also active if the acquisition is interrupted
between the test cycles. As a result the counter types out the absolute angle position at the measurement
output all the time.