# plot parameter for sp500.f
  set xlabel 'time(sec)'
  set ylabel 'Voltage(V)'
  set grid	
plot \
'sp500.dat' using 1:2 title 'External Voltage, Vs', \
'sp500.dat' using 1:4 title 'High_pass(diff.), VR' with lines lw 4, \
'sp500.dat' using 1:5 title 'Low_pass(integ.), VC' with lines lw 4, \
'sp500.dat' using 1:6 title                   'VL' with lines lw 4