| 摘要 |
PURPOSE:To record spectrums with an optimum sensitivity without damaging the shape of a peak waveform by switching preliminarily the gain of an amplifier of a peak waveform signal in accordance with the peak crest value. CONSTITUTION:A spectrum signal Vi of an analytical meter is inputted not only to an amplifier GA1 but also to an amplifier GA2 through a delay circuit DL1. The output of the amplifier GA1 is compared with a reference voltage by a voltage comparator A3, and a scale over detection signal is outputted and is counted by a counter CN1 if said output exceeds the reference voltage; but if the counted value is 0, a switch r1 is closed, and gains of amplifiers GA1 and GA2 are a maximum range R2/R1. If the counted value is ''1'', the switch r1 is opened, and a switch r2 is closed, and gains are switched to R3/R1; and if the counted value is ''2'' because of rise of the signal Vi, gains are reduced to R4/R1. Consequently, the gain of the amplifier GA2 is switched to a proper range before the signal Vi reaches a crest of the peak waveform. |
