... Maximum input voltage30V (DC+AC peak, AC frequency≤1KHz)CALIBRATION SIGNALWaveformPositive-going square waveFrequencyApprox. 1KHzDuty ... limit frequency 10Hz.(With reference to 100KHz, 8DIV, Frequency response with-3dB.)Vertical modesCH1,CH2,DUAL,ADDChopping ... repetition frequencyApprox. 250KHzInput couplingAC, GND, DCMaximum input voltage300Vpeak (AC: frequency 1KHz or ...