- - SUB-BAND SPLITTER UNIT AND ENVLOPE CURVES DETECTOR PROVIDED WITH A SUB-BAND SPLITTER UNIT

摘要

The present invention provides a subband for dividing a wideband input signal (G1), for example, an audio signal into K narrowband sub-band signals (L ₁ , ..., L _k , ..., L _K ). -Relates to a band splitter unit, where K is an integer greater than 1, and the sub-band splitter unit 100 has a wideband input signal and K-1 sub-band filter circuits (SBF ₁ , ..., SBF _k , ..., an input terminal 100 for receiving SBF _K-1 ) is provided, and each of the sub-band filter circuits SBF _k has an input 103.k, a first output 104.k, and Second output 105.k, first filter arrangement LPF _k coupled between input 103.k and first output 104.k, input 103.k and second output 105 .k) is provided with a second filter arrangement (HPF _k ) coupled between, and K output terminals 102.1, ..., 102 for supplying K sub-band signals to the sub-band splitter unit. k, ..., 102.K) are provided. The first output 104.k of the _k -th sub-band filter circuit SBF _k is coupled to the input 103.k + 1 of the (k + 1) -th sub-band filter circuit. The input 103.1 of the first sub-band filter circuit SBF1 is coupled to the input 101 of the sub-band splitter unit. The second output 105.k of the k-th sub-band filter circuit is coupled to the k-th output 102.k of the sub-band splitter unit. The first output 104.K-1 of the (K-1) -th sub-band filter circuit is coupled to the K-th output 104.K-1 of the sub-band splitter unit. The first filter arrangement LPF _k of the sub-band filter circuit is adapted to perform low pass filtering on the signal at the input of the first filter arrangement, and the second filter arrangement HPF _k is the input of the second filter arrangement. It is adapted to perform high-pass filtering on the signal at. In addition, the sub-band splitter unit also has no down-sampling means (FIG. 1). In addition, the present invention provides K input terminals 111.1, ..., 1111.k, ..., 111.K and output terminals 112 for receiving K narrowband sub-band signals. It relates to a sub-band combination unit 110. The sub-band combining unit combines K narrowband sub-band signals for generating a broadband output signal which is a replica of the broadband input signal of the sub-band splitter unit and for supplying the broadband output signal to its output terminal. To adapt. The sub-band combining unit is adapted to add time equivalent samples of K narrowband sub-band signals to produce a wideband output signal. By doing so, there is no upsampling means in the subband combining unit (Figs. 1 and 2). In addition, the present invention proposes an envelope curve detector unit, wherein the envelope curve detector unit includes K-1 sub-band filter circuits of the sub-band splitter unit.