An Improved Measurement Method for Wideband Multi-Frequency Signal

Interharmonics will generate severe mutual interferences and result in measurement errors in wideband multi-frequency signal measurement. Furthermore, the parameters of fundamental wave can also be impacted by its adjacent interharmonics. Under asynchronous sampling condition, the side lobe leakage of fundamental and harmonic components will make the interharmonic components more complicated. To address this issue, this paper proposed a method for wideband multi-frequency signal measurement. First, the multi-interharmonic model was established, and the spectrum separation and measurement (SSM) algorithm was introduced. Then, a quasi-synchronous sampling method can be achieved based on SSM. The complexity of interharmonics is reduced by using the quasi-synchronous sampling process, which can greatly inhibits the fundamental and harmonic interferences. The proposed method has been validated by the synthetic signal. The results show that the dense interharmonics can be identified and measured with relatively high precision.