Optimum frequency test. Z J N f 100 6400 25 0 8 0 0 0 0 0 0 0 0 1498.5 -1500 0 0 1 0 15 1500 -1490 0 0 1 0 25 1490 -1485 0 0 1 0 35 1485 -1482 0 0 1 0 50 1482 -1480 0 0 1 0 70 1480 0 0 0 1 0 100 1600 400 0.5 1.0 1.8 0 5 10 90 3 1 1470 1620 -1 1 1000 0 20.0 20 5.0 65 120 5 1470 1510 12 10 0 100 12 20