外文翻譯--- - 傳感器和傳感器激勵和測量技術(shù)-文庫吧
2025-01-02 23:06 本頁面
【正文】 diagram: typical block diagram of such a system as shown in Figure 3. Through the BF535 DSP processor AD5930 digital waveform generator set. AD5930 needs arising from the sinusoidal output voltage waveform for lowpass filtering and amplification in order to eliminate the master clock (MCLK), mirroring the frequency and high frequency noise generated by feed through. After filtering the sensor signal can be used as a source of excitation frequency. According to the impedance of the sensor response signal amplification may be needed in order to enter the ADC (ADC) dynamic range. Sensor output and the frequency of the source of both incentives into the AD7266 12 bit, 2 MSPS dual simultaneous sampling ADC. ADC output data will be stored in memory in order to do further analysis to calculate the phase and amplitude of the sensor offset. Complete integrated sensor solutions: separation described above is a mon solution for impedance measurement of the sensor solution. The program may require many discrete ponents, so the sensor is a costanalysis solution. These separate ponents will increase their own sources of error. The design of active ponents will increase the number of phase error, which is the need for correction. In addition, the DSP also need to deal with some plex mathematical calculations, this may require external memory to store the original data of the ADC, which would further increase costs. Address the abovementioned analysis of the issue of lowfrequency sensor solutions AD5933 / 4 device, it will by the main processing module are integrated into one chip. The core of the chip, including three main modules: the frequency of scanning for the direct digital synthesizer (DDS) waveform generator。 used to measure the sensor39。s response to the 12 bit, 1 MSPS ADC。 and, finally, to the ADC data for 1024 point Discrete Fourier Transform (DFT) calculations of the DSP engine. The results of DFT calculations to provide a real part (R) and an imaginary part (I) data, which can easily calculate the impedance. Using the following formula is easy to calculate the impedance amplitude and phase: In order to determine the actual value of the real impedance Z (ω), is typically required to perform frequency scanning. Can calculate the impedance of each frequency point, which can draw a relationship between frequency and amplitude curves. So it is easy to measure 100 Ω ~ 20 MΩ resistance within the scope. The system allows users to set up a 2 V peaktopeak (PKPK) of the sinusoidal signal as an external frequency source excitation load. Output range can be set to 1V, 500 mV and 200 mV. Frequency resolution can be 27 bit ( Hz). The realization of the frequency of scanning: In order to achieve the frequency of scanning, the user must first set up the required frequency of scanning conditions: the need for a start frequency, frequency interval and sweep points. Then the need for a start mand to start scanning. Frequency points in each scan, ADC pleted the first 1024 samples, and then calculating the DFT in order to provide the waveform of the real and imaginary parts of the data. The real and imaginary parts of the data through the I2C interface in the form of two 16 bit words available to the user. DSPchip processing unit user does not have the advantage of plex mathematical calculations, and need not store ADC raw data, only two 16 bit data. Therefore, it allows the DSP to choose cheaper solutions, a
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