Abstract: A spectrum analyzer comprises a plurality of filters each provided with a low-pass output and a high-pass output both having the same cutoff frequency which is different in the case of the different filters. Switching means are provided for periodically connecting pairs of filters in cascade during a first time interval between one input for signals to be analyzed and a filtered-signal transmission channel assigned to each pair of filters. One of the filters of each pair has a high-pass (or respectively low-pass) output connected to the input of the other filter whose utilization output is the low-pass (or respectively high-pass) output. The switching means also have the function of periodically establishing a cascade connection during a second time interval between pairs of filters which are different from the first pairs. In the case of one filter, the output utilized during the second time interval is different from the output utilized during the first time interval.