Datasheet

MCP3901 Low-Cost Power Monitor Reference Design
DS51915A-page 16  2010 Microchip Technology Inc.
Although complex, long, finite impulse response (FIR) structures called Sinc Compen-
sation Filters are usually used to compensate for low-pass filter difficulties, they cannot
be implemented in this application because the MCU is being used at close to maxi-
mum computation power.
The appropriate solution is to adjust the cutoff frequency of the IIR HPF to a value at
which the transfer function of the HPF will compensate the Sinc transfer function to
approximately the 50 Hz value. The simulation and the measurements indicate that a
cutoff frequency of 9 Hz for the HPF is the best choice in this case (see Figure 2-6).
FIGURE 2-6: Sinc Filter Compensation Using HPF.