Pre-amplification circuit with high common mode rejection ratio for biological myoelectricity data acquisition system

Abstract

The invention discloses a pre-amplification circuit with a high common mode rejection ratio for a biological myoelectricity data acquisition system. The input end of the pre-amplification circuit is connected with a first electrode and a second electrode. The pre-amplification circuit comprises first to fourteenth resistors, first to fourth capacitors and first to sixth amplifiers which construct the following four circuits: a high pass network, a parallel dual operational amplification amplifier, a high pass differential amplifier with an integral feedback circuit, and a common-mode signal sampling driving circuit. Dual-electrode input is adopted, and the high pass network is arranged at the front ends of the amplifiers without being grounded. If a common mode voltage is input, no current flows through the high pass network, and the potential at each point in the high pass network is equal, so that a common mode signal is not changed into a differential mode signal, and the high common mode rejection ratio can be realized. Moreover, the amplification factor of the pre-amplification circuit is set on a preamplifier, namely, the parallel dual operational amplification amplifier, so that an extremely-high common mode rejection ratio can be provided without intentional matching under the condition of restraining direct-current interference.

Description

technical field [0001] The invention relates to an amplifying circuit of a biological myoelectric data acquisition system, in particular to a high common-mode rejection ratio preamplifier circuit of the biological myoelectric data acquisition system. Background technique [0002] The activity state of the biological body, such as contraction / expansion frequency, contraction / expansion range, etc., will be reflected by bioelectricity (various potentials or currents generated in the body during life activities, including cell membrane potential, action potential, ECG, EEG etc.), so the activity status of the biological body can be understood through the data collection of the bioelectrical signal of the biological body, so as to obtain relevant pathological parameters or health parameters. For example: at the beginning of this century, the electrical activity of the human pregnant uterus was recorded from the body surface for the first time with a galvanometer. Later, relevant ...

AI Technical Summary

Problems solved by technology

For the preamplifier circuit in the existing biomyoelectric data acquisition system, in order to prevent the electrode voltage from causing the high-gain preamplifier circuit to enter a saturated state, a DC blocking capacitor is added to the input end, but because the internal resistance of the signal source is very High, and the two electrodes are unbalanced, the DC blocking capacitor changes the common mode interference into differential mode interference, reduces the common mode rejection ratio, and seriously damages the performance of the preamplifier circuit

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