| 摘要 |
PROBLEM TO BE SOLVED: To realize a data converter, which has good characteristics and is inexpensive though it is a data converter in the adaptive delta modulation system (ADN signal converter) having a simple constitution, and an acoustic device using this data converter. SOLUTION: In the data converter in the delta modulation system where the comparison result obtained by periodically comparing an input signal (VI+) to be converted and a reference voltage (VI-) set in accordance with the preceding comparison result is converted to a continuous digital signal, a D/A conversion circuit is provided which consists of plural current sources (A1 to A8) provided for generation of the reference voltage, switch circuits (S1 to S8) which arbitrarily select the current sources to stepwise set the current value, an integral circuit 32 which generates and changes the reference voltage at a speed corresponding to the set current value, and a control circuit 31 which controls the next connection of switch circuits in accordance with the result of comparison between the input signal and the reference voltage. |
