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Velocity Sensor Acceleration Signal

Sinocera Piezotronics, INC | Updated: Aug 24, 2017

Velocity Sensor Acceleration signal

As the low-frequency vibration of the acceleration signal is very small, and high-impedance small charge signal is very susceptible to interference; when the measurement of the larger the volume, the lower the measurement frequency, the signal signal to noise ratio problem is more prominent. Therefore, in the current with the built-in circuit acceleration sensor is becoming increasingly common in the case should try to use the electrical noise is relatively small, low frequency characteristics of excellent low-impedance voltage output type piezoelectric acceleration sensor.

The low frequency cutoff frequency of the sensor

Similar to the high frequency cutoff frequency of the sensor, the low frequency cutoff frequency is the lowest frequency signal that the sensor can measure at the specified sensor frequency response amplitude error (± 5%, ± 10%, or ± 3dB). The lower the error value, the lower the cutoff frequency is. So the low frequency cutoff frequency indicators of different sensors must be compared under the same error conditions.

The low frequency characteristic of the low impedance voltage output type sensor is determined by the integrated electrical parameters of the sensor sensitive core and the built-in circuit. The frequency response characteristics can be described by the first-order high-pass filter characteristics of the analog circuit, so the low frequency response and cutoff frequency of the sensor can be determined by the time constant of the first order system. From the practical point of view, since the calibration of the very low frequency response of the sensor is difficult, the time constant of the sensor can be measured by the response of the sensor to the step signal in the time domain. Therefore, the low frequency response of the sensor is compared with that of the first order high pass filter Characteristics of almost the same characteristics, through the calculation can easily obtain the low-frequency response of the sensor and its corresponding low-frequency cut-off frequency.

Sensor sensitivity, low frequency noise characteristics and dynamic response range

Sensors for low-frequency measurements generally require relatively high sensitivity to meet low-frequency small-signal measurements. But the increase in sensitivity is often limited. Although the acceleration sensor sensitivity can reach 10V / g or higher, but the high sensitivity often bring other negative effects, such as sensor stability, anti-overload capacity, and the sensitivity of the surrounding environment interference. So the pursuit of high sensitivity does not necessarily solve the measurement of small signals, on the contrary high-resolution and low noise sensors in engineering applications are often easier to solve practical problems. So the choice of sensors with low noise noise in the low frequency measurement is particularly important.