| 摘要 |
Long-time integrator with an a.c. voltage path, which contains a high-pass filter and is connected to the inverting input of a differential amplifier, with a d.c. voltage path, which has a low-pass filter, a modulator, an amplifier, a demodulator and a passive filter and is led to the non-inverting input of the differential amplifier, and with a feedback path, which contains a capacitor and exists between the output and the input of the differential amplifier. The long-time integrator is intended for measuring instruments, in particular flux meters. The corresponding design of the d.c. voltage path is intended to achieve the effect that the signals leaving the main amplifier are freed of long-term fluctuations and recognisable as reproducible integrals of the input voltage signals. To this end, the modulator and the demodulator are operated in push-pull mode and an active filter is arranged between the demodulator and the passive filter. <IMAGE>
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