| 摘要 |
PURPOSE:To remove a noise without fail by changing a set amplification factor so that the output level of an amplifying circuit can be in a fixed range. CONSTITUTION:When the set amplification factor of a variable amplifying circuit 1' is 50dB, the amplitude of a fine amplitude input signal 21 passes through the circuit 1' and an amplifying signal 22', for which a truth signal component amplitude achieves a saturation level and a noise amplitude goes to be 2.5V, is obtained. Then, the noise is not removed in a peak clamp circuit 2. Next, when the set amplification factor is 35dB, the amplifying signal 22', for which the truth signal component amplitude is 1.4V and the noise amplitude is 0.44V, is obtained and this noise is removed in the circuit 2. Then, only a truth signal component is obtained as a peak clamp signal 23. The signal 23 is transformed to a logical level in a comparing circuit 3 and defined as a detecting signal 24. |
