| 摘要 |
PURPOSE:To limit the waveform of an object signal to a level less than a constant value so as not to generate distortion by monitoring the level of the object signal always fluctuating, generating a control signal based on an output signal, and adjusting the level of the object signal. CONSTITUTION:An input signal Sin increasing gradually is inputted to a comparator 11 via a multiplier 14. The comparator 11 outputs a signal Sc with short pulse width when the level of the input signal i.e., the output signal Sout arrives at a limit value VLIM. A signal generator 12 receives the signal Sc, and performs a fast integral action when the signal Sc is set at an H level, and outputs the control signal Sg by discharging when it is set at an L level. A subtractor 13 receives the signal, and subtracts it from a reference level value Vo, and generates a differential signal VCNT, then, supplies it to the multiplier 14. The multiplier 14 multiplies the differential signal VCNT by the input signal Sin. In other words, the gain of the multiplier 14 which decides a ratio of input/ output of a device is controlled by the differential signal VCNT, thereby, the waveform of the object signal Sout can be limited to the level less than the constant value so as not to generate the distortion. |
