Abstract
Signal simulator and integrated circuits in microelectronics under the constant development of technology arising out of an incentive to source equipment that can meet the needs of a variety of signals has been widely applied to satellite communications, aerospace, instrumentation and other areas. This paper designed to simulate a rotating machine shaft vibration signal simulator.
The article first outlines the development process of frequency synthesis, frequency synthesis of traditional technology, phase-locked loop frequency synthesis and direct digital frequency synthesis for comparison. Then, in theory, the digital frequency synthesis of the basic structure and working principle. Selected according to the design requirements of the major components, the system according to the characteristics of direct frequency synthesis and SCM technology design of rotating machinery vibration signal simulator. The design is done using SCM STC89S52 superposition of high harmonics of the fundamental signal and the signal generated. Circuit control hardware FIFO-type memory timing output vibration signal waveform. At the same time using the classical ping-pong type of storage and direct memory access (DMA) control methods, namely, hardware-timed control circuit Dual Dual FIFO-type memory to meet the harmonic requirements of continuous output signal simulator.
In the design, the system according to the functions of vibration signal simulator is divided into several different functional modules: SCM modules, memory modules, interactive modules, low-pass filter module. In this paper, the hardware design of each module are described in detail.
Finally, the paper on the harmonic signal simulator system noise analysis, amplitude quantization error, digital to analog conversion errors and other problems on a detailed analysis, and gives two common methods suppress harmonic signal simulator.
Key words direct digital frequency synthesis; SCM; signal simulator; shaft vibration signal