... voltage-controlled oscillator, Three working modes MCH-2893A Speaker Tester, impedance test ModelMCH2893ATest parameterImpedance /Z/ ZZero clearing 0Short ... frequency 4 digits, impedance 4 digits LED 4 4Test signal Test frequency Fixed frequency: 400Hz, 1kHz 400Hz-1kHzManual adjusting ... change witout prior notice. MCH Speaker Impedance Tester,MCH-2893A Speak tester,400Hz,1KHz fixed freq,20Hz-4Khz manual ...