Frequency band division filter - has low-pass filter output subtracted from input signal, and LF and HF signal parts delivered at separate outputs

摘要

The filter has a low-pass filter (12) connected to the input terminal, with a steep characteristic at the cut-off frequency. A delay circuit (11) is connected in parallel with the low-pass filter (12), with a frequency-phase characteristic very much the same as that of the low-pass filter (12) in its pass band. A subtraction circuit (15) is connected to the outputs of the low-pass filter (12) and the delay circuit (11). The first output terminal (13) delivers the band-pass filter (12) output signal, while the second output terminal (16) delivers the h.f. band of the subtraction circuit (15) output. Transmission characteristics between the input terminal (10) and the output terminals (13, 16) are similar to the frequency-amplitude and frequency-phase characteristics of the delay circuit (11).