| 摘要 |
<p>PURPOSE:To perform encoding with high efficiency at a high speed, by dividing a signel space according to the mean value of a block previously and quantizing them by vectors. CONSTITUTION:An input signal sequence is divided into K (K: integer greater than 2) blocks and inputted to a register 5 as input vectors. At this point of time, a mean value computing element 6 calculates the amplitude mean value of the K blocks and sends the mean value to a code table switch 7. The switch 7 sets a threshold value to the mean value to decide which of output vector code table memories 9 and 10 is referred to; and output vectors are read out of the selected memory by a code table address counter 8 and compared with the input vectors, and element distortion is calculted by a parallel subtracter 12 and a parallel absolute value computing element 13. The maximum value of the element distortion is detected by a detector 14 while the minimum distortion is detected by a detector 15, and they are latched in an index latch 18 as the vector quantization outputs of the input vectors and inputted to a decoder. The decoder latches a signal from an encoder in the latch 18 to select the memory 9 or 10, obtaining an output vector 20.</p> |
