| 摘要 |
PURPOSE:To perform the data compression with no reduction of the S/N regardless of a decreased mean data length, by expressing the finite difference value of the great number of times of appearance with a small data length and the finite difference value of the small number of times of appearance with a large data length respectively. CONSTITUTION:For a differential coder, the sampled input signal is turned into a finite difference value with subtraction given to the previous process value through a subtracting part 1 and quantized at a quantizing part 2 and also coded at a coding part 3 to be transmitted or stored in the form of a coding data. On the other hand, a differential demodulator decodes the input coding data to a finite difference value through a decoding part 6. This finite difference value is added with the previous value through an adding part 7 to be used as the present value. This present value is delivered in the form of signals. The present value is held for a sampling period at a delaying part 8 and then set equal to the previous value due to the finite difference value of the next coding data. |
