The design of virtual signal generator

The traditional signal generator has the disadvantages of complex circuit structure, huge volume, poor stability and accuracy due to employ analog circuit technology. Compared with the traditional instruments, virtual instrument have no instrument panel. What´s more PC powerful graphical environment and processing ability are used to establish graphical virtual instrument panel, which can complete instrument control, signal generation, data acquisition, data analysis and data display etc. In this paper, a virtual signal generator, which uses PC sound card instead of commercial data card, is designed based on virtual instrument special-purpose language LabVIEW. The signal generator, including signal produce module and sound output module, can produce sine wave, square wave, triangle wave and sawtooth wave. Frequency, amplitude and phase can be changed in a certain range according to necessary, and the sound card can also be used to output waveforms.