You are here: NI Home > Support > Product Reference > Manuals > LabVIEW 8.5 Help

Filters x using an equi-ripple bandstop FIR filter model.

This VI is similar to the Equi-Ripple BandStop VI.

Details  

	initialize, when TRUE, initializes the internal state of the VI.
	higher pass freq must be greater than higher stop freq and observe the Nyquist criterion. The default is 0.4. If higher pass freq is less than or equal to higher stop freq or does not meet the Nyquist criterion, the VI sets Filtered x to zero and returns an error through the Parks-McClellan VI.
	lower pass freq must be greater than zero and observe the Nyquist criterion. The default is 0.2. If lower pass freq is less than or equal to zero or does not meet the Nyquist criterion, the VI sets Filtered x to zero and returns an error through the Parks-McClellan VI.
	x is the input signal to filter.
	sampling freq: fs is the sampling frequency and must be greater than zero. The default is 1.0.
	# of taps must be greater than 2. The default is 31. If # of taps is less than or equal to 2, the VI sets Filtered x to 0 and returns an error through the Parks-McClellan VI. Note  The Parks-McClellan algorithm introduces a large error when you design a bandstop filter for an even number of taps. To avoid this error, the Equi-Ripple BandStop PtByPt VI adjusts the number of taps to the next higher odd value if # of taps is even.
	lower stop freq must be greater than lower pass freq and observe the Nyquist criterion. The default is 0.25. If lower stop freq is less than or equal to lower pass freq or does not meet the Nyquist criterion, the VI sets Filtered x to zero and returns an error through the Parks-McClellan VI.
	higher stop freq must be greater than lower stop freq and observe the Nyquist criterion. The default is 0.35. If higher stop freq is less than or equal to lower stop freq or does not meet the Nyquist criterion, the VI sets Filtered x to zero and returns an error through the Parks-McClellan VI.
	Filtered x contains the result of filtering the input sequence x by convolution.
	error returns any error or warning from the VI. You can wire error to the Error Cluster From Error Code VI to convert the error code or warning into an error cluster.

Equi-Ripple BandStop PtByPt Details

Generates a bandstop FIR digital filter with equi-ripple characteristics using the Parks-McClellan algorithm and higher pass freq, lower pass freq, # of taps, lower stop frequency, higher stop freq, and sampling freq. The Equi-Ripple BandStop PtByPt VI then applies a linear-phase, bandstop filter to x to obtain Filtered x.

The first passband region of the filter goes from zero (DC) to the lower pass freq. The stopband region goes from the lower stop freq to the higher stop freq. The second passband region goes from the higher pass freq to the Nyquist frequency.