ICP DAS USA CAN-2084C, Application User'S Manual

Page: 15 / 36

CAN-2084C
User’s Manual (Version 1.00, Sep/2018) ------------- 15
Refer to the following table for details of how to set the Low Pass Filter:
An example is illustrated in the following figure:
In this example, H < T and the high width of the input signal < the period of the filtering
clock, and so the signal will be filtered.
Supposed T = 1 ms, that is the filtering clock has a frequency of 1 kHz. Now, if the
duty cycle of the input signal is 50%, that is the high width is equal to the low width,
then:
H < T
➙
H < 1 ms
➙
input signal period < 2 ms (duty cycle = 50%)
➙
input frequency > 500 Hz,
Consequently, the input signal will be filtered.
Now, if the duty cycle of the input signal is 25%, that is the low width is three
times the high width, then:
H < T
➙
H < 1 ms
➙
Input signal period < 4 ms (duty cycle = 25%)
➙
Input frequency > 250 Hz,
Consequently, the input signal will be filtered.
Similarly, the maximum period of the filtering clock can be calculated to allow the input
signal to be passed using the formula H > 2T.