Signal Conditioning-level adjustment

Signal Conditioning is to adjust the output digital signal to conform to the subsequent interface processing. generally, it is a level signal. The input signal should be half of A/D. analog and digital interfaces generally require signal isolation (magnetic isolation of transformer and Optical Isolation of photocoupler)-signal preprocessing-removing useless signals (filtering ). there are four types of signal conditioning: new type conversion filtering and impedance matching of the level adjustment linear signal.

Level adjustment: The maximum magnification and circuit should be removed based on the output level range of the sensor and the level range of the acquisition end, and a certain margin should be kept.

1 passive level adjustment: generally achieved through the Partial voltage circuit (the accuracy requirement of the partial pressure resistance)

2. Active level adjustment: The level adjustment with the amplifier as the core (the characteristics of the ideal operational amplifier, single-ended input (same phase end/inverse phase end input)/differential input, magnification operation, integration/differential/index/logarithm circuit/voltage follower circuit and features)

Single-ended reverse-phase input amplification circuit: Feedback resistance function: stable circuit, determines the magnification. The output voltage is related to the input voltage and the magnification. When the input signal is too large, the output will be "de-peaked"

Voltage follower: Same-phase input, reverse-phase output

Integrated circuit: the capacitor is fed back to the input segment through negative feedback.Point drift, usingParallel Connection between resistance and feedback capacitor

Differential Circuit: the resistance and capacitance position of the integrated circuit are switched to a differential circuit. The output is sensitive to input changes and has poor anti-interference.

Exponential circuit (optical battery/PN junction characteristics): The original component in the input channel is a diode or transistor.

Logarithm circuit: replace the original input channel and the original Feedback Channel of the exponential circuit.

Differential Circuit: two inputs U0 = (U2-U1) r input/R same phase end grounding resistance.

 

Signal Conditioning-level adjustment