In Amplitude-Shift Keying (ASK) modulation, the voltage threshold for triggering a Voltage-Controlled Oscillator (VCO) will depend on the specific design and characteristics of the modulation scheme and the VCO circuit being used.
ASK modulation involves varying the amplitude of a carrier signal based on the input data signal. When the data signal is high (logic 1), the carrier signal's amplitude is typically increased, and when the data signal is low (logic 0), the carrier signal's amplitude is decreased or turned off.
The voltage threshold for triggering the VCO in an ASK modulation system will be determined by the circuit's design, including factors such as the desired modulation index (the extent to which the carrier signal's amplitude is varied), the input signal's amplitude range, and the VCO's characteristics.
In some cases, the threshold might be set to activate the VCO when the input signal crosses a certain voltage level, ensuring that the changes in amplitude correspond appropriately to the modulation scheme. However, the specific voltage threshold value will vary based on the requirements of the modulation scheme and the electronic components being used.
If you are designing an ASK modulation system and need to determine the voltage threshold for your VCO, you would need to consult the specifications and datasheets of the components you are using, and potentially perform simulations or experiments to optimize the threshold value for your specific application.