Research On Multi-component Mixed Signal Generator

Signal generator is an electronic measuring instrument for testing excitation signal.The common types are function generator and arbitrary waveform generator.Function generator can output a variety of ideal standard function waveforms,but it cannot produce more complex components of the signal.Widely used arbitrary wave generator can produce complex waveforms,but the waveform changing operation is complicated and it will show a periodic waveform after working for a long time.At some laboratories for test,such as simulation for marine sonar signal,require multiple independent components superimposed waveform signal.This paper will research the synthesis method of multi-component mixed signals.Traditional method to produce multi-component mixed signal is superposing the analogy signals after hardware circuit produces them,which makes the hardware cost high and size big.To overcome the above shortcomings,this paper proposes a multi-component mixed signal circuit design method.Making full use of FPGA technology and signal transformation technology instead of waveform memory and DAC,which greatly increases the number of components and simplifies the hardware circuit.The amplitude,frequency,initial phase and other parameters of every component can be independent setting.This paper proposes the overall design scheme of multi-component mixed signal generator.This solution is composed by the function of logic control signal digitalsystem and realizing the function of signal transformation and channels of analog circuits.The digital system design bases on the multiple sinusoidal components as an example to study the frequency,amplitude and phase of setting method.Digital part includes interface unit,clock generating circuit,logic unit,pulse amplitude logic unit and phase frequency logical unit.With 9 components signal generator as an example,the design of analog circuit sets four parts by using analog switch technology and filtering technology:amplitude transformation,pulse transform,sine mixed and superposition of all components.Through the simulation analysis,it confirms that the use of storage resources of the programmable logic devices makes the extension number for the components feasible.The design possesses the characteristics which make the circuit simple,power consumption low,synchronization easy.This design is especially suitable for applications required excitation waveform of multi-source independent superposition and long running time.