System and method for determining the longitudinal mode frequency required for color mixing in a discharge lamp

摘要

In a power source system, a method for providing color mixing in a high intensity discharge (HID) lamp comprises the steps of providing a swept frequency signal having a sweeping frequency ranging between a first lower frequency value and a second higher frequency value, within a specified period. An amplitude modulation signal is also provided having an adjustable frequency value and an adjustable modulation index. As a result the sweeping frequency signal is modulated by said amplitude modulation signal. The frequency of the amplitude modulation signal is adjusted until a maximum lamp voltage is detected. Thereafter, the system operates with a modulating frequency that yields the maximum lamp voltage so as to substantially eliminate color segregation in the lamp.