Device for combined B-scan and B/A imaging

A device for the production of both conventional and B/A second order non-linearity images of objects, notably biological tissues, by ultrasound echography comprising:

• an ultrasound transducer;
• transmitter means connected to the transducer to produce repeated transmission of pulses of ultrasound energy;
• receiver means connected to the transducer for receiving signals which correspond to echoes of the pulses of ultrasound energy which are received by the transducer, said receiver means comprising:
• an amplifier, with automatic gain control, connected to receive and amplify signals from the transducer;
• a first processing channel for producing conventional images, having an input connected to the output of the amplifier and comprising, in functional cascade connection, a first envelope detector and first display means;
• and
• a second processing channel for producing B/A second order non-linearity images, having an input connected to the output of the amplifier and comprising, in functional cascade connection, a bandpass filter, a second envelope detector, comparison means which compare the output of the first envelope detector with the output of the second envelope detector, differentiation means, and second display means;
• wherein the transducer has a bandwidth which is approximately equal to or greater than one octave, the transmitter means comprise means for generating transducer activation signals having the nominal frequency f.sub.0 in the vicinity of the lower limit of the bandwidth of the transducer, the spectrum of the activation signals excludes a frequency f.sub.1 =2f.sub.0, and the bandpass filter has a central frequency equal to said frequency f.sub.1.