| 摘要 |
PURPOSE:To eliminate the need for a large input range for arithmetic processing, by converting a level of a receiving signal to a level within the optimum range for the arithmetic processing in response to the said level, calculating a tentative initial gain adjusting value, inverting the result of operation to be obtained again and restoring the range to the range of the input signal. CONSTITUTION:A gain adjusting value is multiplied by an inverting constant 1/alpha at a multiplication section 5a of a level converting section 5. Then, the gain adjusting value corresponding to an input average level in the input range is obtained. A gain control section 6 is provided wth a switch 6a. The switch 6a is operated to set the gain adjusting value outputted from a level converting section 5 to an initial tap register 6b at the initial state, i.e., signal acquisition. In setting the initial gain adjusting value to the tap register 6b, the received signal value is multiplied by the gain adjusting value of the said tap register 6b at a multiplication section 6c and outputted externally as a received signal value adjusted with the gain. |
