Design Of Signal Conditioning And Processing Carrier Board Of Dynamic Signal Analyzer

As the main tool for mechanical fault diagnosis, modal analysis, electronic design and acoustic test, a dynamic signal analyzer can integrate such signal functions as generation, acquisition, processing and display, thereby realize the time-domain, frequency-domain and amplitude-domain analysis for signals to be tested. It features broad dynamic range, high sensitivity, and multi-channel and multi-test mode.This thesis mainly discussed the design of the signal input conditioning channel, built-in signal source and DSP system for the four-channel dynamic signal analyzer.First of all, in order to realize the sinal conditioning with an amplitude range of-51dBVrms~+25dBVrms, the design makes a multi-stage adjustment by passive attenuation, fixed and programmable gain. In order to achieve the conditioning and quantization with a dynamic range of greater than 90 dB, the design takes advantage of the out-of-band-signal suppression characteristics of the oversampling in Σ-ΔADC. Also, the consistency of all channels, and improve channel isolation are discussed in detail.Secondly, the design of signal source circuits were accomplished based on the demand for built-in signal source analysis. In order to achieve the generation and output of various forms of wave, the audio chip was selected with dual output configuration; moreover, the signal output channels can adjust signals by programmable gain, programmable attenuation and offset adjustment.Thirdly, the design of master control system for instruments was accomplished in DSP system. This part introduced the communication and control interface of DSP system, and then completed the multi-channel and multi-mode control system to instruments, and explained the power-on self-starting design and memory management scheme for DSP system.Finally, by the instrument debugging and testing, the design scheme was proved to be able to meet the expected goals by verifying the consistency of all channels, the channel isolation, and the performance of test control for multiple instrument mode also was smooth and reliable.