A Design of a Digital Correlator for Microwave Holography Based on the ROACH Platform

We have developed a real-time digital correlator for microwave holography based on the ROACH hardware platform. This correlator has high levels of flexibility and extensibility. First, the correlator does not require any baseband transformation for its input signals. This is achieved by using bandpass sampling to dramatically simplify the hardware system for microwave holography. Second, the sampling rate of the correlator is adjustable within the range 10Mbps to 1000Mbps. Together with the use of a digital frequency mixer and a digital filter, this makes it convenient to adjust bandwidths and frequency resolutions of signals. Our test results show that the correlator has a high measurement precision and a high level of stability, which should ensure accurate and reliable results in future applications.