Ultrasonic imaging method and apparatus for generating pulse width modulated waveforms with reduced harmonic response

An ultrasound apparatus for transmitting ultrasonic energy at a fundamental frequency for receipt of reflected ultrasonic energy at a harmonic of the fundamental frequency comprising:

• a transducer;
• and
• a signal generator connected to said transducer, and operative to generate a sequence comprising at least first and second pulses, each pulse characterized by a respective pulse duration, said pulse duration modulated such that the pulse durations for the first and second pulses differ from one another.

An ultrasound apparatus for transmitting ultrasonic energy at a fundamental frequency for receipt of reflected ultrasonic energy at a harmonic of the fundamental frequency, said apparatus comprising:

• a transducer;
• and
• a waveform generator connected to said transducer and operative to generate an ordered sequence of a plurality of pulses, wherein a first duration between a first and second pulse is different than a second duration between said second pulse and a third pulse.

In a method comprising the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency in an ultrasound system, an improvement wherein step (a) comprises the step of:

• (a1) transmitting a waveform comprising a plurality of pulses in an ordered sequence, wherein a first duration between first and second pulses is different than a second duration between said second pulse and a third pulse.

In a method comprising the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency in an ultrasound system, an improvement wherein step (a) comprises the step of:

• (a1) transmitting a waveform comprising a plurality of pulses, at least a first and second pulse having a first and second pulse duration, said first pulse duration different than said second pulse duration and determined as a function of an approximation of an energy content of a transmit waveform comprising an envelope shape rising gradually to a respective maximum value and falling gradually from the respective maximum value.

In a method comprising the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency in an ultrasound system, an improvement wherein step (a) comprises the step of:

• (a1) transmitting a waveform comprising a plurality of pulses, at least a first pulse comprising a first pulse duration, wherein the duration between said first pulse and a second pulse is different than said first pulse duration.