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Voltage Controlled Oscillator

This example shows you how to model an ideal voltage controlled oscillator using the Variable Pulse Generator block to create the frequency oscillations.

A voltage controlled oscillator uses an input tuning voltage to produce waveforms of varying frequency. Over a small range of voltages, the relationship between the input voltage ($V_{in}$)and the output oscillation frequency ($F$) is proportional and can be expressed as

$$F(t) = K_c . V_{in}(t) + F_0 (1)$$


  • $K_c$ is the oscillator sensitivity in Hz/V

  • $f_0$ is the quiescent frequency, or nominal frequency of the oscillator at $V_{in} = 0$

In the included vco_using_vpg model, the desired oscillation frequency signal F_{in}(t) is generated using the formula shown in equation (1). In this model, the tuning voltage $V_{in}$ is a sinusoidal waveform.

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