In this paper we introduce the developmental phase and experimental equipments of long time delay phase-locked loop and also give the field test results via the satellite "Symphonic".

Delayed scan, the hypodense edema ring enhanced and became isodense, or the abscess enhanced diffusely, the lesions became smaller and the colliquative necrosis area more obvious.

The effects of the square wave cycle, phase, duty cycle and the fiber coil group delay and amplifier gain bandwidth on the bias error of closed-loop FOG were analyzed by simulating and testing.