Phase I of the proposed program addresses the feasibility of designing a precision phase and amplitude controller which will provide phase and amplitude accuracy of 0.1 degree and 0.1 dB respectively over an instantaneous bandwidth of 1 GHz. It is shown that this performance can be achieved by utilizing a high dynamic range I-Q vector modulator along with a simplified error correction scheme which minimizes memory requirements. The I-Q vector modulator utilizes proprietary technology as well as a high performance microwave quadrature coupler to obtain broadband performance well in excess of the desired 1 GHz bandwidth and, in fact, can span a bandwidth ratio of more than three to one in the frequency range from 0.5 GHz to 18.0 z. The phase and amplitude controller will be digitally programmable and a study will be performed to optimize the interface with the VME bus. Phase I of the program will generate the system design and will include a demonstration of a unit with the required amplitude and phase resolution over a limited dynamic range. Requirements for calibration and performance verification will be reviewed as part of this effort. Phase II will include fabrication and testing of complete phase and amplitude controller with the full 30 dB dynamic range and VME bus interface.
