MIK-RD908/909雷達液位計天(tian)(tian)線(xian)發(fa)(fa)射極(ji)(ji)窄(zhai)的(de)(de)(de)(de)(de)微(wei)波(bo)脈(mo)(mo)(mo)沖(chong)(chong)，這個脈(mo)(mo)(mo)沖(chong)(chong)以光速在空間(jian)(jian)(jian)傳播(bo)(bo)，遇到(dao)(dao)被測介(jie)質(zhi)表面，其部(bu)分能量被反射回來(lai)，被同一(yi)(yi)天(tian)(tian)線(xian)接收。發(fa)(fa)射脈(mo)(mo)(mo)沖(chong)(chong)與(yu)接收脈(mo)(mo)(mo)沖(chong)(chong)的(de)(de)(de)(de)(de)時(shi)間(jian)(jian)(jian)間(jian)(jian)(jian)隔(ge)(ge)與(yu)天(tian)(tian)線(xian)到(dao)(dao)被測介(jie)質(zhi)表面的(de)(de)(de)(de)(de)距離成正比(bi)。由于電磁波(bo)的(de)(de)(de)(de)(de)傳播(bo)(bo)速度(du)極(ji)(ji)高(gao)，發(fa)(fa)射脈(mo)(mo)(mo)沖(chong)(chong)與(yu)接收脈(mo)(mo)(mo)沖(chong)(chong)的(de)(de)(de)(de)(de)時(shi)間(jian)(jian)(jian)間(jian)(jian)(jian)隔(ge)(ge)很(hen)(hen)小（納(na)秒量級）很(hen)(hen)難確認，MIK系列908雷達液位計采用一(yi)(yi)種特殊的(de)(de)(de)(de)(de)解(jie)調技術，可以準確識別(bie)發(fa)(fa)射脈(mo)(mo)(mo)沖(chong)(chong)與(yu)接收脈(mo)(mo)(mo)沖(chong)(chong)的(de)(de)(de)(de)(de)時(shi)間(jian)(jian)(jian)間(jian)(jian)(jian)隔(ge)(ge)，從(cong)而進(jin)一(yi)(yi)步計算出(chu)天(tian)(tian)線(xian)到(dao)(dao)被測介(jie)質(zhi)表面的(de)(de)(de)(de)(de)距離。