Signal amplitude expander with limiter

Abstract

Abstract PURPOSE: To prevent the S/N deterioration in case the input noise level is high by stopping the expanding action of the expander when the input signal voltage is high and then giving the control so that the expander may function as an amplifier featuring the fixed gain. CONSTITUTION: The input signal sent from input terminal 1 is applied to analog multiplier 5 as well as to limiter 6. In case the voltage of the input signal is lower then the action level of limiter 6, the voltage is detected through detector 3 to be applied to LPF4. Then the output voltage the ripple component of which is eliminated by LPF4 is supplied to multiplier 5, and the signal obtained by expanding the input signal with the fixed multiplying factor is delivered to output terminal 2 of multiplier 5. While in case the input signal is over the action level of limiter 6, the limit level is set for the output level of limiter 6 so that it may start operation with the input voltage of OdB. And when the input noise level is higher than OdB, no expansion is given to the noise level. Thus the S/N deterioration can be prevented for the output signal of output terminal 2 of multiplier 5. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Takeshi Toyoda

Bibliographic Details