The invention provides an LDPC
encoder based on DVB-S2 standard multi-rate compatibility, which comprises a
control signal generation unit and a check bit updating unit. The
control signal generation unit generates, according to set encoding rates and an encoding initial identifier
signal, a
state control signal for controlling operation of the entire
encoder, a plurality of addresses of corresponding rows in an address table, which are provided by easy input information bit to be encoded correspondingly to a DVB-S2 standard, and control identifier signals corresponding to the encoding rates, and outputs the
state control signal, the addresses and the control identifier signals to the check bit updating unit; the check bit updating unit carries out
binary addition operation on the information bits to be encoded and check bits read from the plurality of addresses corresponding to the information bits to be encoded, and writes an operation result into an original address. According to the LDPC
encoder provided by the invention, by separately designing a
control unit and an operation unit, the LDPC encoder compatible to various code rates is implemented; and encoding operation of the corresponding code rates can be completed only by setting the corresponding encoding rates at an
external interface.