Reliability of communication system is very important. E1 error-free transmission device

called EFTD

is then developed for this purpose. The equipment uses ATmega128 as the processor platform

while uses FPGA to capture synchronization. In transmitter of EFTD the E1 signal is duplicated and then transmitted through two routes

while in receiver the two signals with different delay should be received and keep mutual coherence. These two signals are error checked and compared. The better one is then chosen and outputted.