A Multiplierless Parallel Digital Down Converter for High Resolution Spaceborne SAR

High resolution spaceborne SAR has unique advantages in target recognition and earthquake rescue due to its refined description of target characteristics. The resolution is developing from the meter level to the decimeter level, which brings a huge increase in signal bandwidth. The traditional analog demodulation or serial digital down-conversion processing methods are no longer suitable for the needs. In addition, the limited scale of the onboard digital processing chip makes it impossible to simply copy the serial processing into a multichannel parallel mode. In this paper, a novel digital down converter is designed according to the band-pass sampling theorem and the fast finite impulse response algorithm (FFA) combined with the characteristics of the spaceborne digital processing chip. Compared with the traditional method, the resource consumption of the proposed method is obviously improved. With the increase of the signal bandwidth, this advantage is more obvious. The proposed method is suitable for high-resolution spaceborne SAR, large bandwidth millimeter wave radar, etc.