| 摘要 |
PURPOSE:To designate the characteristic at a logarithmically uniform interval extending over a wide band in a frequency area, by constituting the titled filter so that an output signal of each filter stage is controlled as to its phase and amplitude, respectively, and thereafter, added and becomes an output signal of the whole. CONSTITUTION:An input signal from an input terminal IN is A/D-converted by a sampling frequency f0 by an A/D converter, and applied to a digital filter F0 of a band pass characteristic. An input signal of the first stage filter F0 has a frequency spectrum as shown by (a), and an output signal becomes that which has fetched a formation of the uppermost octave as shown by (b). When its output signal is subtracted from the input signal of F0, it becomes a signal of a frequency spectrum as shown by (c), and this signal is inputted to a filter F1 of the first stage. As for an output signal of each filter stage, multipliers b0-b3 are multiplied by a coefficient bi, and its phase characteristic is designated by a delay element tau'i, and thereafter, it is added by an adder ADD and becomes an output signal of the whole.
|
