Wide spectral span Spectrum Analysis with an analog step and dwell translation pre-processor to a high dynamic range FFT based spectrum analyzer

This paper describes a new high speed Spectrum Analysis technique that tiles a spectral display using a rapid step and dwell spectral sweep. The step and dwell translation operates as a block down converter that translates successive frequency spans to an IF filter which is sampled, A-to-D converted, and processed by a high dynamic range FFT spectrum analyzer. The step and dwell sweep of the analog block down converter enables sequential spectral probes reminiscent of a swept frequency analyzer. The windowed FFT performed during the dwell synthesizes a parallel filter bank that partitions the spectral span into the same resolution bands as an FM spectral sweep through the same spectral span. By performing this second partition in parallel rather than sequentially we can reduce the time duration required to sweep the desired spectral span or we can implement post detection averaging by performing multiple FFTs during each dwell interval. The rapid spectral sweeps that can be realized by this technique make the analyzer well suited for analyzing transient and non periodic input signals.