Symbol synchronization performance using loop switching type quenching method

In symbol synchronization of high speed burst communication which operates at a transmission rate higher than 10 Mbps, fast acquisition performance is an important subject. Generally, in the clock recovery circuit which uses a tank filter with a high Q value, interburst interference between the recovered clock signals becomes a significant problem. As a method to solve this problem, we propose the loop switching type quenching method, with which the output clock signal of the tank filter is fed back into the tank filter during a guard time, and is combined in antiphase with the remaining clock signal. Therefore, the output signal is forced to be refreshed. Thus this quenching method can remove the interference to the desired clock signal. This paper describes a new scheme and gives simulation and experimental results when this method is applied to a DQPSK system. The results show that no matter how high the Q value of the tank filter is, interference can be removed by using this quenching method, resulting in a significant improvement