| 摘要 |
PURPOSE:To attain highly accurate digital signal processing by providing a compression circuit before an A/D converter and providing an expansion circuit after the A/D converter so as to improve the quantization accuracy of thc A/D converter without increasing the cost. CONSTITUTION:This circuit consists of an AGC circuit 1, a compression circuit 2 having a standard gamma-nu characteristic, a general 8-bit A/B converter 3 and an expansion circuit 4 expanding 8-bit into 10-bit and correcting the compression error of the compression circuit 2. Through the constitution above, an original signal is inputted through a switch 8, compressed by the compression circuit 2 via the AGC circuit 1, digitized by the A/D converter 3, the result is expanded by a ROM 11 and the characteristic change due to temperature of the compression circuit 2 is corrected by the RAM 15 to attain accurate expansion. Then the processing is applied by a digital signal processing circuit 38, D/A-converted by the D/A converter 5 and outputted through an LPF 6. |
