Digital adaptive heterodyne filter adopts the heterodyne-modulation conception, which makes the filter work in low frequency and lessens the complexity of design.
数字自适应外差滤波器运用外差调制的概念，使滤波在低频率处操作，从而降低了滤波器的复杂程度。
2
The principle and experimental results of phase modulation optical heterodyne detection technique for measuring reflection of optical cavity are described.
本文叙述了用位相调制光外差技术探测光学谐振腔反射特性的原理及实验结果。
3
Optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy (OH-MR-VMS) is an absorption spectroscopic technique for selective detection of the molecular ions.