The present invention relates to an electromagnetic acoustic transducer excitation system comprising a tone burst generator, the tone burst generator comprising: an oscillator device configured to produce a radio frequency signal; an analog switch configured to produce an output based on the radio frequency signal produced by the oscillator device and a control signal; a pre-amplifier configured to amplify the output of the analog switch and produce a tone burst output signal; and a control module configured to produce the control signal for providing to the analog switch.

The present invention relates to an electromagnetic acoustic transducer excitation system comprising a tone burst generator, the tone burst generator comprising: an oscillator device configured to produce a radio frequency signal; an analog switch configured to produce an output based on the radio frequency signal produced by the oscillator device and a control signal; a pre-amplifier configured to amplify the output of the analog switch and produce a tone burst output signal; and a control module configured to produce the control signal for providing to the analog switch.

Aspects of this disclosure relate to reducing settling time of a sawtooth ramp signal in a phase-locked loop. Information from a loop filter of the phase-locked loop can be stored and used within the loop filter so as to improve the settling time of the sawtooth ramp signal. In certain embodiments, the settling time of a periodic sawtooth ramp signal can be reduced to less than one microsecond. An output frequency at the end of the sawtooth chirp can be brought back to an initial value without significantly modifying phase error in disclosed embodiments.

Disclosed is an apparatus for generating high-quality sine waves through a simple circuit structure. The apparatus comprises a square wave generator for generating a plurality of square waves different in frequency from one to another; a combined circuit for combining the plurality of square waves into a synthetic wave; and a filter circuit for filtering the synthetic wave through a low-pass filter. Also, a method for generating high-quality sine waves is provided.

Disclosed is an apparatus for generating high-quality sine waves through a simple circuit structure. The apparatus comprises a square wave generator for generating a plurality of square waves different in frequency from one to another; a combined circuit for combining the plurality of square waves into a synthetic wave; and a filter circuit for filtering the synthetic wave through a low-pass filter. Also, a method for generating high-quality sine waves is provided.

A high-voltage transmitting circuit (100) for a catheter, and an ablation tool (1000). A first electrode (P1) and a second electrode (P2) are provided on the catheter. The high-voltage transmitting circuit (100) comprises: a first transmitting circuit (110), wherein a first end of the first transmitting circuit (110) is connected to a high-voltage positive electrode (+HV), a second end of the first transmitting circuit (110) is connected to a high-voltage ground (GND), and a third end of the first transmitting circuit (110) is connected to a high-voltage negative electrode (HV); a filtering circuit (120), wherein an input terminal of the filtering circuit (120) is connected to a transmitting terminal of the first transmitting circuit (110), an output terminal of the filtering circuit (120) is connected to the first electrode (P1), and the second electrode (P2) is connected to the high-voltage ground (GND); and a control circuit (130), wherein the control circuit (130) is used for controlling the first transmitting circuit (110) to output an alternating-current (AC) square wave, which is subjected to filter processing by the filtering circuit (120) to form a sine wave between the first electrode (P1) and the second electrode (P2). In this way, the output of pulsed voltage waveform of the sine wave is realized, and therapeutic requirements in some ablation operations by pulsed electric field are satisfied, thereby expanding the application prospects of ablation technique by pulsed electric field in arrhythmia treatment.

A system and method for generating a radio frequency (RF) waveform are described. The method includes defining a train of on-off pulses separated by an off state having no on-off pulses. The method further includes applying a multi-level pulse waveform that adjusts a magnitude of each of the on-off pulses to generate an RF waveform. The method includes sending the RF waveform to an electrode.