plot "tp.dat" using 1:3 title "input" with linespoints, "tp.dat" using 1:5 title "two pole" with linespoints, "tp.dat" using 1:7 title "78LAG" with linespoints, "tp.dat" using 1:5 title "two pole" with linespoints "tp.dat" using 1:9 title "LAG78 TWICE" with linespoints