Effective frequency selection algorithm for bandpass sampling of multiband RF signals based on Relative Frequency Interval

In design of software receiver, costs of AD converter is greatly decreased and data amount is largely reduced by using bandpass sampling. However, the interval of sampled signal in spectrum is ignored in related researches, especially in multiband RF signals´ sampling by single frequency. To solve the problem, we introduce RFI (Relative Frequency Interval) as one important criterion to evaluate performance of sampling frequency. Based on RFI, we propose and infer an effective selection algorithm to get the optimal sampling frequency. In application of GPS receiver, we implement the proposed algorithm with numerical method to get available sampling frequency, which directly determines data amount and the corresponding RFI value. Then according to actual demand, we can get the optimal sampling frequency.