1517015 B-scan ultrasonoscopes N C PICKERING and N R BRONSON 18 Sept 1975 38313/75 Heading G1G A signal processing apparatus for a B-scan ultrasonoscope having a transducer for transmitting acoustic energy pulses and receiving reflected echo pulses, the apparatus comprising means 50 for converting the transducer output signal into a series of pulses 51 whose amplitudes represent the intensities of the echo pulses and whose spacing represents the distance from the transducer to a reflecting-body, means 52A-52N for converting the series of pulses into a corresponding series of digital signals, each digital signal representing a corresponding pulse amplitude, encoding means 58 for converting the series of digital signals into binary coded decimal values, and de-coding means 62 for converting the binary coded decimal values into a series of signals, each signal representing a corresponding pulse amplitude, these signals being applied to respective colour generating means of display tube means. As shown, the comparing means comprise a series of comparators 52A-52N which compare each pulse amplitude with different references derived from a voltage divider chain comprising resistors 56a-56n, to provide the digital signals. Each output line of the de-coder 62 includes a respective resistor 64a-64n, the values of these resistors having a linear relationship, a logarithmic relationship, or a relationship corresponding to the voltage-brightness curve of the display tube. Pulses which fall into a first, low amplitude range generate a signal from the de-coder 62 for energizing the blue gun of the colour display, pulses on a middle amplitude range cause the green gun to be energized, and pulses in a high amplitude range cause the red gun to be energized. A colour display tube of the single gun type may alternatively be used. To improve the quality of spot on the display, the transducer, eg a Piezo-electric transducer 80, is energized by the circuit shown in Fig. 3. A first trigger circuit 84 causes energization of the transducer, and after a delay provided by unit 86, a second trigger circuit 85 applies a second energizing pulse to the transducer. This pulse coincides with the second positive oscillatory swing of the transducer output signal and is stated to cause damping of the transducer oscillations and improve the quality of echo pulse.
展开▼
