A polyphase digital down converter method for GHz high speed sampling signal

For the limitation of the processing speed in hardware, the traditional down-conversion doesn´t work for GHz high speed sampling signal. In this paper, a novel approach is proposed with polyphase decomposition to achieve the down-conversion of the GHz high speed sampling signal. In this method, the input high speed sampling signal and the corresponding oscillation signal are parallelized to be M sub-channels of low speed sampling with delay and decomposition approach, which can be viewed as polyphase decomposition. The down-conversion operation is performed for each channel of input data. Then the down-conversion of the GHz high speed sampling signal is derived with the down-conversion results of each channel. The simulations verify the effectiveness of the proposed method.