MATLAB: Does the Voltage-Controlled Oscillator (VCO) block from the Communications Blockset 2.5 (R13.0.1) give an incorrect output when the input signal is zero

communicationscommunications blocksetoscillatorvcovoltage-controlled

According to the help, the VCO output frequency should be the "Oscillation Frequency" specified in the mask. However, in my model, the VCO output frequency appears to go to zero when the control input is zero. Is there a bug in the block?

Best Answer

This is not a bug in the Communications Blockset 2.5 (R13.0.1).
For the VCO block, the "oscillation frequency" is the center frequency (also known as the quiescent frequency), which will correspond to the output of the block when there is a constant input. The input sensitivity scales the input signal to the block thus affecting the output signals frequency also.