| 摘要 |
A frequency sweep system (10) operating in the radio frequency range includes a pulse source, a reflective array compresser (RAC) (13) and a complex multiplier (15). The RAC is designed to apply a time dispersion as a monotonic function of frequency to a pulse generated by the pulse source. Since RACs are difficult to manufacture precisely, the complex multiplier is included to compensate for the imperfections in the RAC. The complex multiplier is designed to multiply its analog input by a sequence of complex digital words, including a sign bit, so that the phase and amplitude of the analog signal can be calibrated as required. The sequence of digital words is determined by comparing the desired and actual phase dispersions of the frequency sweep system. The sequence so determined is stored in a read-only memory (ROM) (17). A timing generator (19) coordinates the firing of the pulse and the introduction of the sequence of digital words into the complex multiplier. A limiter (23) is included to reduce amplitude fluctuations as a function of frequency at the RAC output, and to reduce the bandwidth requirements of the processor. A filter (21) is included to smooth the "steps" introduced by the digital processing, so that, for example, an ideal linear frequency sweep can be achieved.
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