# Graphs of Lanczos window
# Central lobe of normalized sinc, scaled to different widths

# Set terminal
set terminal svg enhanced size 300 200 fs 10
set samples 1001  # high quality
set border 31 linewidth .3 # thin border

set output "lanczos-windows.svg"

# Ranges
set xrange [-3:3] # Widest window is -3 to 3
set xtics .5      # Accords with existing graphs, provides scale
set yrange [-.1:1.1] # Slight headroom from max of 1
set ytics .2      # Accords with existing graphs

# Zero axes as guidelines, no key (self-explanatory)
set zeroaxis
unset key

###########################
# Define and plot function
###########################

sinc(x) = sin(pi*x)/(pi*x) # Normalized sinc

set parametric # Parametric to provide alt ranges
plot [t=-1:1]   t, sinc(t), \
              2*t, sinc(t), \
              3*t, sinc(t)