For the point measurement of the time-varying magnetic field of deflection yoke from 100Hz to 100KHz, a small search coil having the rectangular cross section of 2 millimeter by 3 millimeter and an integrating amplifier having a flat gain of about 40dB in the required frequency band are designed, fabricated, and tested. Exciting solenoid coil having the diameter of 120 millimeter and the length of 100 millimeter is also fabricated and generates the magnetic field from 0.1 Gauss to about 50 Gauss over the band from 50Hz to 7.5MHz. The measurement shows that this system is linear in measuring the field strength from 1 Gauss to 52 Gauss less than ±1 percent error in the frequency range from 100Hz to 100KHz.
