Equi-Ripple HighPass (Not in Base Package)

Generates a highpass FIR filter with equi-ripple characteristics using the Parks-McClellan algorithm and the # of taps, stop freq, high freq, and sampling freq. The Equi-Ripple HighPass VI then applies a linear-phase, highpass filter to the the input sequence X using the Convolution VI to obtain Filtered Data. Details

X is the input signal to be filtered.
# of taps must be greater than zero. The default is 31. If the number of taps is less than or equal to zero, the VI sets Filtered Data to an empty array and returns an error through the Parks-McClellan VI. The VI does not place restrictions on the # of taps, but # of taps should be odd.
Note  The Parks-McClellan algorithm introduces a large error when designing a highpass filter for an even number of taps. To avoid this error, the Equi-Ripple HighPass VI adjusts the number of taps to the next higher odd value if # of taps is even.
stop freq must be greater than zero. The default is 0.2. If stop freq is less than or equal to zero, the VI sets Filtered Data to an empty array and returns an error through the Parks-McClellan VI.
high freq must be greater than stop freq and observe the Nyquist criterion.

where is stop freq, is high freq, and is sampling freq: fs. If any of these conditions are violated, the VI sets Filtered Data to an empty array and returns an error through the Parks-McClellan VI. The default is 0.3.

Note  All cutoff frequencies must be less than half .
sampling freq: fs is the sampling frequency and must be greater than zero. The default is 1.0.
Filtered Data The VI filters by convolution. The number of elements, k, in Filtered Data is

k = n + m - 1,

where n is the number of elements in X, and m is the number of taps.

A delay is also associated with the output sequence

error returns any error or warning from the VI. Refer to Signal Processing Error Codes for more information about these conditions.

Equi-Ripple HighPass Details

The stopband of the filter goes from zero (DC) to the stop freq. The transition band goes from the stop freq to the high freq, and the passband goes from the high freq to the Nyquist frequency.