| 摘要 |
PURPOSE:To prevent the accuracy of range finding from being deteriorated by performing gain control where a noise component only is taken into notice so as to output a range finding signal at a proper level at all times against the change in the multiplex modulation of an input signal and in a range finding frequency. CONSTITUTION:A band of a BPF13 for detecting noise extracting only the noise component is set to a band at the outside of range finding signals 9, 10 and a command signal 12. When the S/N of the input is large, the input to a square detector 7 is minute noise only and the system is not operated as a gain control system, but when the S/N of the input is small, that is, the noise level is larger, the system acts like the automatic gain control system so as to suppress the noise level to a prescribed level, thereby causing the operation of the system to suppress the signal. Since the automatic gain control takes only the noise as the reference, even if the command signal 12 is applied at the same time, the system is not susceptible to the effect and attains suitable control. |
