| 摘要 |
PURPOSE:To input an analog input signal at a high speed with high accuracy, by controlling both the modulation time of a transformer and the time constant of a filter circuit in response to the level of the input analog signal. CONSTITUTION:A CPU9 gives an analog signal input to a control part 8, and the part 8 decides the modulation time of a transformer and the time constant of a filter circuit 5' by the discrimination signal supplied from a scanner board control circuit 11 via a signal line 101. Then the modulation time is set to the circuit 11; while the time constant is set to the circuit 5'. The circuit 11 controls the modulation time and a switch 2 and a multiplexer 12 and makes a pulse transformer 3 give modulation to an input signal. This modulated input signal is amplified by an amplifier 4 and cut off with its noises by the circuit 5' to be demodulated by a sample holding amplifier 6. The demodulated signal is supplied to the CPU9 under the control of the part 8 and via an input/output bus 10 after an A/D conversion. |
