High resolution frequency analyser for video-data telecommunications signal

摘要

The frequency analyser (HRSFFT) receives an input signal (Vt) via an A/D converter (1) and a storage unit (2). The analyser contains a window weighting block (3), FFT block (4), interpolation evaluation unit (5), spectrum interpolator (7), inverse FFT (8), timebase accumulator (9), subtractor (11), frequency accumulator (12) and adder (13). The interpolation evaluation unit distinguishes between a true line spectrum and an amplitude fluctuation broadened line spectrum by means of an inverse FFT back-converting the spectrum interpolator acquired frequency domain data to time domain data. The processed time domain data is subtracted from the original time domain data, and the result is input to a window weighting block and FFT process. Frequency domain data is accumulated, and a vector sum (Sf) with the transformation output signal is output via an FFT to a display (6).