| 摘要 |
An analog radio frequency spectrum analyzer (10) includes a calibration section (30) for compensating distortions. The spectrum analyzer includes a first reflective array compressor or "RAC" (12), a frequency sweep section (20), and a second RAC (14). Frequency domain compensations introduced at the signal input by the calibration section compensate distortions in the time domain at the output of the spectrum analyzer. This system corrects, for example, nonlinearities in the second RAC. The calibration function is determined by a network analysis of the spectrum analyzer and is specific to the RAC included. The function is stored in a ROM or other memory as a sequence of complex digital words. An address generator (36) directs the words to a complex multiplier (32) so that each input symbol period is multiplied by the sequence. Each complex digital word corresponds to an amplitude and phase modulation of the incoming signal over a fraction of a symbol period. The resulting output of the spectrum analyzer is that which would be expected without calibration given an ideal second RAC.
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