锁相环在相位噪声测试中的工作机理和影响

分析了相位检波技术测试相位噪声的工作原理和锁相环在电路中的工作机理,给出了锁相环对相位噪声测试影响的转移函数,通过对环路修正前和修正后的实际测试曲线的比较,很容易看出环路噪声压缩的影响。明确了在实际测试中,必须对锁相环带宽内的相位噪声曲线进行修正。通过分析可以看出,用相位检波器方法使相位噪声测试由测信号相位起伏变成测电压起伏,用锁相技术使压控参考源与被测源同频,并可有效地对锁相带宽内噪声抑制进行修正,改进了相位噪声测试的方法。

Principle and Effect of the Phase Lock Loop in Phase Noise Measurement

The operation principle of phase detector measuring phase noise and the mechanism of the phase lock loop(PLL)in the circuit were analyzed.The PLL phase noise transfer function was given,and the effect of PLL phase noise compression was observed through the comparison of corrected and uncorrected phase noise curves within PLL BW.The results show that phase noise curves must be corrected within PLL BW,voltage fluctuations transform into combined phase fluctuations at two input sources with the phase detector,...