| 摘要 |
PURPOSE:To detect whether the amplification factor of an amplifying circuit and the frequency characteristic of a filter circuit are normal or not by comparing a prescribed input signal, which is inputted to the amplifying circuit, with an output signal which is outputted through this amplifying circuit and the filter circuit. CONSTITUTION:Before the measurement of an electrocardiogram, in order to automatically diagnose whether an amplifier 4 and a low-pass filter 5 are normally operated or not, the two types of sine wave signals, whose amplitude is fixed and frequency is different, are inputted to the amplifier 4. Then, the amplitude of the output signal, which is amplified by this amplifier 4 and passed through the low-pass filter 5, is compared with the amplitude of the input signal which is inputted to the amplifier 4. Thus, it is judged whether the amplification factor of the amplifier 4 and the frequency characteristic of the low-pass filter 5 are normal or not. Here, in order to exactly record an electrocardiographical waveform, the low-pass filter 5 needs the passing characteristic of $30% at 100Hz. Then, the sine wave signals to have the two types of the frequencies such as 10Hz without attenuation and the high band interrupting frequency 100Hz having 30% attenuation are inputted to the amplifier 4. |
