function eval_lfo()

L = 10000;
fs = 44100;
fstart = 40;
fend = 400;
df = (fend-fstart)/L;

ip = 0 % phase of the first output sample in radians
w = freq*pi / samplerate
b1 = 2.0 * cos(w)

% Init
y1=sin(ip-w)
y2=sin(ip-2*w)

% Loop
for n=1:L,
    
y0 = b1*y1 - y2
y2 = y1
y1 = y0


close all

figure;
plot(1:L, vsaw, 1:L, vblit); grid;

wavwrite(0.5*vtri, fs, 'tri.wav');
wavwrite(0.5*vsqr, fs, 'sqr.wav');
wavwrite(0.5*vsaw, fs, 'saw.wav');
wavwrite(0.5*vblit, fs, 'blit.wav');