PURPOSE: To improve the S/N of an objective sound among background noise by providing a clip circuit and a nonlinear amplifier so as to suppress components below noise level and to amplify components over the noise level.
CONSTITUTION: An output signal of a microphone 1 is applied to a filter 4. An output signal of the filter 4 is applied to the clip circuit 5. The clip level is sufficiently lower than the amplitude of the objective sound signal and the S/N of the output signal of the clip circuit 5 is improved. The output signal of the circuit 5 is applied to the nonlinear amplifier 6. The level of the nonlinear amplifier 6 is set to a value around the maximum amplitude of noise components remained in the output signal of the circuit 5. The amplitude of the components below the said level is compressed and the amplitude of the components over this level is expanded. As a result, the noise components of the output signal of the nonlinear amplifier 6 is suppressed into a signal where the objective sound signal is emphasized thereby improving the S/N remarkably.
| JPS58141019 | NOISE GENERATION PREVENTING CIRCUIT |
| WO/2020/023856 | FORCED GAP INSERTION FOR PERVASIVE LISTENING |
AWANAKA YASUAKI
ARIKI YOSHIO
