Patent ID: 7458935

Claim:
A method for transmitting ultrasound pulses and receiving echo signals at a harmonic of the transmission frequency comprising the following steps: generating a signal for exciting a plurality of transducers for transmitting at least one ultrasound pulse at a basic transmission frequency; receiving a reflection echo of said at least one ultrasound pulse at a harmonic of the frequency of the at least one ultrasound pulse; removing any contributions to the harmonic frequency in the signal for exciting; filtering the signal for exciting by using a transmitting resonant circuit having a resonance frequency which is adjusted to the basic transmission frequency, wherein an assembly of the plurality of transducers and a cable connecting said plurality to a transmitter that is constructed and arranged for performing said generating step is constructed and arranged as said transmitting resonant circuit, the assembly having a resonance frequency; providing a variable inductance in series between the cable and the transmitter for calibrating the resonance frequency of the assembly to said the transmission frequency; and automatically adjusting the variable inductance based on electrical characteristics of the assembly.