Programmable oscillator uses digital potentiometers

摘要

Digital potentiometers are versatile devices; you can use them in many filtering and wave-form-generation applications. This Design Idea describes an oscillator in which setting the resistance of two digital potentiometers independently programs the oscillation amplitude and frequency. Figure 1 shows a typical diode-stabilized Wien-bridge oscillator that generates accurate sine waves from 10 to 200 kHz. In this classic oscillator circuit, the Wien network comprising R, R', C, and C', provides positive feedback, and R_1 and R_2 provide negative feedback.