svfilter from last dst lab hw

svfilter.m

function svfilter(cutoff, Q)

	% lowpass
	[lpf_b, lpf_b] = fir1(10, cutoff, 'low');

	% highpass
	[hpf_b, hpf_b] = fir1(10, cutoff, 'high');

	% bandpass
	% For bandpass coefficients, the order is half of the passed in order parameter (has to be an even order beacuse of poles and zeroes)
	bw = cutoff / Q;
	Wn = [cutoff - bw / 2, cutoff + bw / 2];
	if (Wn(1) <= 0 || or Wn(2) >= 1)
		warn('Center frequency and Q problem . . . .');
		b_bp = 1;
		a_bp = 1;
	else
		[bpf_b, bpf_b] = fir1(5, cutoff, 'bandpass');
	end

	% display
	if b_bp == 1 && b_bp == 1
		fvtool([lpf_b, lpf_a], [hpf_b, hpf_a]);
	else
		fvtool([lpf_b, lpf_a], [hpf_b, hpf_a], [bpf_b, bpf_a]);
	end
end