| 摘要 |
<p>PURPOSE:To identify and detect assuredly a required signal from an input signal low in SN by amplifying and processing the input signal with an amplification characteristic increasing its amplification factor as the increment of an input level. CONSTITUTION:A video signal A detecting an echo from a radar or the like is inputted to a DC component removing circuit 2, its DC component is removed and a video signal B consisting of an AC component is inputted to an absolute value circuit 3. The circuit 3 rectifies the full wave of the signal B, inverts the negative level and inputs an absolute value output signal C to a variable amplitude amplifier part 4. The amplification part 4 regulates the amplification factor by a variable resistor 42 and inputs an amplitude-amplified signal D to a weighting amplification part 5. The amplification part 5 amplifies the input signal D by a non-linear amplifier 51 and a variable resistor 52 with an amplification factor corresponding to the size of input level of the input signal D, expands the level difference between an required sigal S and a noise N and outputs a signal E to an offset amplification part 6 and a terminal 72. The amplification part 6 removes a noise level less than the offset and outputs only a required signal F to a terminal 71.</p> |
