Mixed-frequency suppressed-wave device used for mixed-frequency tests

The utility model discloses a mixed-frequency suppressed-wave device used for mixed-frequency tests. The mixed-frequency suppressed-wave device comprises a support capacitor connected on the two ends of a DC bus in a parallel way for ensuring voltage stability on the DC bus; a voltage-boosting/decreasing chopper circuit connected on the two ends of the support capacitor for boosting or decreasing the voltage on the support capacitor when the voltage on the support capacitor is too low or too high; and a controller having an input connected on the support capacitor so as to detect the voltage on the support capacitor and outputs connected on the control ends of the voltage-boosting/decreasing chopper circuit. When the voltage exceeds a preset first threshold value, the controller sends out a control signal to make the voltage-boosting/decreasing chopper circuit to work in a voltage-decreasing chopper state. When the voltage is lower than a preset second threshold value, then the controller sends out a control