FILTERING AN ANALOG INPUT SIGNAL
An analog input is filtered using an algorithm which accurately retranscribes the properties of an analog "low-pass" filter. A "low-pass" filter returns the input signal in full (frequency, amplitude and shift). Its frequency is much lower than a characteristic filter frequency and is known as the "cut-off frequency". As the frequency of the input signal nears the "cut-off frequency", the output signal (which has the same frequency) becomes increasingly attenuated and out-of-phase. When the frequency of the input signal reaches the "cut-off frequency", the output signal is attenuated by approximately 30% and is out-of-phase by 45°. If the frequency reaches and exceeds the "cut-off frequency", the attenuation increases significantly (reaching total elimination) and the shift approaches 90°.
The "cut-off frequency" can be adjusted (indirectly, because the "low-pass" filter is implemented digitally) in the parameterisation window of the symbol.