3) Excitation oscillator contains less than 1 per cent second harmonic, which in turn is attenuated 80 dB by filtering. 80 dB + 30 dB ... wave it is possible to get a pure sine wave second harmonic output which greatly increases the signal-to- noise ratio of the device. ... 4) A description of the helical core sensor is given together with circuit diagrams of the electronics. Schmitt, O.H. Unbalanced magnetometer. U.S. Patenta#39;T 2, 560, 132, July 10, 1951. ... Serson, P.H., and W.L.W. Hannaford.
|Author||:||Danske meteorologiske institut|