| 摘要 |
An echo signal which has been emitted by an ultrasonic scanner (11) and reflected by a body to be investigated, is amplified by means of a logarithmic amplifier (15) and amplitude-demodulated by a detector (16). An adder stage (17) adds to the demodulated echo signal an afterecho attenuation voltage, an amplification control voltage and an amplification regulation feedback voltage. The amplification-regulated echo signal passes from the adder stage (17) to a multiplier stage (21) and is multiplied by a dynamic control voltage and a negative dynamic regulation feedback voltage. The negative dynamic regulation feedback voltage is obtained by integrating the output signal of the multiplier stage (21) and subsequently inverting and amplifying the signal. <IMAGE>
|
