Simultaneous RF monopolar calibration using a shared return electrode

A system comprising:

• a first electrosurgical instrument;
• a second electrosurgical instrument;
• and
• an electrosurgical generator, comprising:
• a clock source outputting a clock signal;
• a first radio frequency source including:
• a first power supply configured to output a first direct current waveform;
• a first radio frequency inverter coupled to the first power supply and the first electrosurgical instrument, the first radio frequency inverter configured to supply a first radio frequency waveform from the first direct current waveform to the first electrosurgical instrument;
• and
• a first controller configured to control the first radio frequency inverter based on the clock signal;
• and
• a second radio frequency source including:
• a second power supply configured to output a second direct current waveform;
• a second radio frequency inverter coupled to the second power supply and the second electrosurgical instrument, the second radio frequency inverter configured to generate a second radio frequency waveform from the second direct current waveform to the second electrosurgical instrument simultaneously as the first radio frequency waveform;
• and
• a second controller configured to control the second radio frequency inverter based on the clock signal,
• wherein the clock source is a common frequency source for each of the first controller and the second controller and is used to synchronize operation of the first controller and the second controller and the first radio frequency waveform and the second radio frequency waveform, respectively.