Ma Yangxue, Liang Dong, Peng Di, Zhang Zhiyao, Zhang Yali, Zhang Shangjian, Liu Yong
Opt Express. 2017 Feb 6;25(3):2355-2368. doi: 10.1364/OE.25.002355.
An approach to microwave frequency measurement with a high resolution and a broad bandwidth is proposed based on three parallel low-speed photonic analog-to-digital converters (ADCs) architecture. Through simultaneously bandpass sampling the input microwave signal with the three photonic ADCs, the input frequency can be calculated from the Fourier frequencies of the photonic ADCs using the proposed frequency recovery algorithm. Theoretical analysis and simulation results indicate that the proposed method is applicable for both single-tone and multi-tone microwave signals. By employing three ~1 GS/s@8 bits photonic ADCs, 0-100 GHz frequency measurement with an error of ± 0.5 MHz and a spur-free dynamic range of 94 dB-Hz over the full band has been numerically demonstrated. Additionally, a proof-of-concept experiment is carried out to demonstrate the effectiveness of the proposed method, where a frequency measurement range of 0-20 GHz with a measurement error of ± 8 kHz is realized by utilizing three photonic ADCs with sampling rates of 27.690 MS/s, 27.710 MS/s, and 27.730 MS/s. Larger frequency measurement range can be achieved by using an optical modulator with a larger bandwidth.
基于三个并行低速光子模数转换器（ADC）架构，提出了一种具有高分辨率和宽带宽的微波频率测量方法。通过使用这三个光子ADC同时对输入微波信号进行带通采样，可以使用所提出的频率恢复算法从光子ADC的傅里叶频率计算出输入频率。理论分析和仿真结果表明，该方法适用于单音和多音微波信号。通过采用三个~1 GS/s@8位光子ADC，数值验证了在全频段内0-100 GHz频率测量的误差为±0.5 MHz，无杂散动态范围为94 dB-Hz。此外，还进行了概念验证实验以证明该方法的有效性，通过使用采样率分别为27.690 MS/s、27.710 MS/s和27.730 MS/s的三个光子ADC，实现了0-20 GHz的频率测量范围，测量误差为±8 kHz。使用具有更大带宽的光调制器可以实现更大的频率测量范围。
