The invention discloses a method for
processing a
broadband receiving
digital front end, which comprises the following steps that: 1, received
radio frequency signals are divided into n paths of signals, and each path of the signals is subjected to
frequency mixing respectively, and the difference of the frequencies of the
frequency mixing among the paths is 80 MHz, then the paths of signals are processed respectively and are transmitted to an AD (Analogue-
Digital Converter) for sampling with the sampling frequency of F1, and digital
medium frequency signals with the centre frequency of F2 and the bandwidth of 80MHz are generated by each path, and are transmitted to a FPGA (Field Programmable Gata Array) for
processing; 2: a corresponding AD is selected to input signals according to a current
signal frequency code of the
system, a DDS (Digital Display Scope) is controlled to generate orthogonal digital local oscillation consistent with a
signal frequency spectrum sampled by the AD, the signals input by the AD are multiplied by the orthogonal digital local oscillation generated by the DDS respectively and the
frequency spectrum is shifted to a zero
intermediate frequency to carry out
orthogonal decomposition to acquire an I path of
baseband signals and a Q path of
baseband signals which are orthogonal to each other; and 3: the velocity of a
signal data stream acquired after theshift of the
frequency spectrum is F1, the signals are subjected to extraction filtering for M times by using a CIC extraction filter to acquire an I
baseband signal and a Q baseband signal with the velocity of F1 / M, and the baseband signals are subjected to complementary filtering respectively by using an FIR low-pass filter.