Generator for digitally generating electrical signal waveforms for electrosurgical and ultrasonic surgical instruments

A method of generating electrical signal waveforms by a generator, the generator comprising a digital processing circuit, a memory circuit in communication with the digital processing circuit, a digital synthesis circuit in communication with the digital processing circuit and the memory circuit, and a digital-to-analog converter (DAC) circuit, the memory circuit defining first and second lookup tables, the method comprising:

• storing, by the digital processing circuit, phase points of a first digital electrical signal waveform in the first lookup table defined by the memory circuit, wherein the first digital electrical signal waveform is represented by a first predetermined number of phase points, wherein the first predetermined number of phase points define a first predetermined wave shape;
• storing, by the digital processing circuit, phase points of a second digital electrical signal waveform in the second lookup table defined by the memory circuit, wherein the second digital electrical signal waveform is represented by a second predetermined number of phase points, wherein the second predetermined number of phase points define a second predetermined wave shape;
• and
• receiving, by the digital synthesis circuit, a clock signal, and at each clock cycle:
• retrieving, by the digital synthesis circuit, a phase point from the first lookup table;
• retrieving, by the digital synthesis circuit, a phase point from the second lookup table;
• and
• determining, by the digital processing circuit, whether to switch between the phase points of the first and second electrical signal waveforms or to synchronize the phase points of the first and second electrical signal waveforms.

A generator for generating electrical signal waveforms, the generator comprising:

• a digital processing circuit;
• a memory circuit in communication with the digital processing circuit, the memory circuit defining a lookup table;
• a digital synthesis circuit in communication with the digital processing circuit and the memory circuit, the digital synthesis circuit receiving a clock signal;
• and
• a digital-to-analog converter (DAC) circuit;
• wherein the digital processing circuit is configured to:
• store phase points of a digital electrical signal waveform in the lookup table defined by the memory circuit, wherein the digital electrical signal waveform is represented by a predetermined number of phase points, and wherein the predetermined number phase points define a predetermined wave shape;
• and
• retrieve a phase point from the lookup table at each clock cycle;
• and
• receive a feedback signal associated with a tissue parameter;
• and
• modify the predetermined wave shape according to the feedback signal;
• and
• wherein the DAC circuit is configured to convert the retrieved phase point to an analog signal.