Suppressing acoustic resonance in HID lamp with combined frequency modulation

The acoustic resonance phenomenon occurs in high intensity discharge lamp operating in high frequency with appropriate activation frequency and enough energy at the same time. A combination of nonlinear frequency modulation and low frequency amplitude modulation is proposed to spread the output spectrums over a broad frequency band, to lessen the amplitudes of different frequencies, to reduce the activation energy, to prevent the plasma acoustic waves from being the standing waves, and then suppresses the acoustic resonances effectively, and also the experimental results are given out in this paper.