Patent ID: 7580843

Claim:
A synthesis subband filter process for 18 sets of signals which each comprises 32 subband sampling signals, the subband sampling signals being in accordance with a specification providing 512 window coefficients (D 0 ˜D 511 ), said process comprising the steps of: (a) sequentially processing said 18 sets of signals, and performing the following steps for said set of signals being processed: (a-1) by use of 32-points discrete cosine transform (DCT), converting said 32 subband sampling signals into 32 converted vectors and writing said 32 converted vectors into 512 default vectors (V″ 0 ˜V″ 511 ) with a first-in, first-out queue; and (a-2) generating 32 pulse code modulation (PCM) signals (S 0 ˜S 31 ) according to the 512 default vectors (V″ 0 ˜V′ 511 ), the specification and the following formulae: S 16 ⁢ = ∑ i = 1 , 3 , 5 , … ⁢ , 15 ⁢ ( - V 32 ⁢ i ″ ) * D 32 ⁢ i + 16 , ⁢ S j ⁢ = ∑ i = 0 , 2 , 4 , … ⁢ , 14 ⁢ V 32 ⁢ i + 16 + j ″ * D 32 ⁢ i + j + ∑ i = 1 , 3 , 5 , … ⁢ , 15 ⁢ ( - V 32 ⁢ i + 16 - j ″ ) * D 32 ⁢ i + j ⁢ ⁢ for ⁢ ⁢ j = 0 ~ 15 , ⁢ and ⁢ ⁢ S 32 - j ⁢ = ∑ i = 0 , 2 , 4 , … ⁢ , 14 ⁢ ( - V 32 ⁢ i + 16 + j ″ ) * D 32 ⁢ i + 32 - j + ∑ i = 1 , 3 , 5 , … ⁢ , 15 ⁢ ( - V 32 ⁢ i + 16 - j ″ ) * D 32 ⁢ i + 32 - j ⁢ ⁢ for ⁢ ⁢ j = 1 ~ 15 , wherein i and j are both integer indexes ranging from 0 to 15.