An implementation of the ASI loop output circuit in the DVB-IP gateway is introduced.The implementation which simply realizes the loop output of 270Mbps ASI transport stream is based on the chip PE- 65508

CLC014 and CLC006.The paper first mentions the features of ASI and SPI

then describes the circuit in detail

and gives out the test result at last.In the test

the loop output signal is amplified by 1.8 times.The loop output function is so strong that it can meet the requirements of re-transport after loop output and multilevel loop output.