| Communications Blockset | |
Voltage-Controlled Oscillator
The Voltage-Controlled Oscillator block generates the synthesized signal (along with Convert to Square Wave subsystem) and adjusts the frequency of the synthesized signal according to the Voltage-Controlled Oscillator input signal.
When the control signal is close to its steady state value of 7/4, the Voltage-Controlled Oscillator block generates a signal whose frequency is close to fr*N/M, which is 100 MHz for the model's pre-assigned parameters. If the output frequency drops, the control signal will rise, boosting the frequency of the output signal. If the output frequency rises, the control signal will fall, lowering the output frequency.
Double-click on the Voltage-Controlled Oscillator block to open the mask.
The Oscillation frequency parameter is just the quiescent frequency, fq. The difference between the block's output signal frequency and the oscillation frequency is proportional to the input signal, interpreted as voltage. The oscillation frequency is set to the variable fq, which is initially assigned a value of 30 MHz. You can change this value in the Oscillation frequency dialog box, or by changing the value of fq at the MATLAB prompt.
The Input sensitivity parameter scales the input voltage, and thus controls the shift from the oscillation frequency. The units of the parameter are Hertz per volt. The input sensitivity is set to the variable sen, which is initially assigned a value of 40 MHz/V.
Changing the values of fq and sen will not affect the steady-state frequency of the synthesized signal, because the corresponding change to the gain value exactly compensates for the change.
| | Gain Block | Simulation Parameters | |
