| 摘要 |
PURPOSE:To reduce power consumption by constituting an amplitude constant circuit outputting the amplitude of an input signal while making it constant in accordance with the control signal from the outside of a CMOS circuit. CONSTITUTION:The output of a variable gain amplifier circuit 1 is inputted to a peak holding circuit 3. A voltage comparator 5 compares the output of the peak holding circuit 3 with the output of a reference voltage circuit 6. A peak detection circuit 4 detects the peak on the positive side in a sine wave to be the output of an oscillation circuit 2. A counter 7 counts peak every time the peak detection circuit 4 detects the peak. The output data of the counter 7 changes the amplification factor in the variable gain amplifier circuit 1 via a latch circuit 8. When the output of the voltage comparator 5 is inverted in the latch circuit 8, the output data of the counter 7 is latched and the variable gain amplifier circuit 1 outputs constant amplitude. |
