ABSTRACT
Wien's bridge oscillator circuit is a kind of energy which can be converted to DC with a certain frequency and amplitude, as well as the exchange of a certain energy output waveform of the circuit. Digital Wien's bridge has the flexible FM, wide output frequency scale, and powerful features, so it has a wide range of applications, such as communications, radio, automatic control, and also many other fields.
This issue analyzed the Wien's bridge oscillator circuit characteristics, and also proposed a digital FM method. In this design, X9511W was chosen to replace the potentiometers in the FM circuit. By adjusting the resistance of the digital potentiometer to change the output frequency. At the same time, to meet the start-up conditions, the potentiometer was also used to replace the thermistor which in negative feedback network.
This issue carried out the principle of circuit emulation and debug. Theoretically, it was able to meet the characteristics of Wien 's bridge FM oscillator. However, the digital potentiometer resistance adjustment resolution was limited, the oscillatior output frequency was not precise, and the signal was ringing easily.
Keywords: Wien's bridge oscillator； Digital Potentiometers；X9511W；Frequency Modulation
