Method and means for generating time gain compensation control signal for use in ultrasonic scanner and the like
First Claim
1. A method of generating a time gain compensated signal in an ultrasonic scanner and the like comprising the steps of generating electrical signals in response to reflections of an ultrasonic wave, applying said electrical signals to a variable gain amplifier, storing digital codes indicative of desired gains in a random access memory, selectively addressing said random access memory whereby a variable digital code is obtained, applying said digital code to a digital to analog converter means to thereby derive an analog control signal, and applying said analog control signal to control the gain of said variable gain amplifier.
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Abstract
Time gain compensation is provided in an ultrasonic scanner by storing a digital code in memory representing the desired signal gain for intervals of time during the reflected wave. Gain compensation due to transducer parameter can be provided in digital form in a separate memory, and the outputs of the two memories are combined and applied to a digital to analog converter. The resulting analog control signal is preferably filtered and then applied as a control signal to a gain control amplifier.
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11 Claims
- 1. A method of generating a time gain compensated signal in an ultrasonic scanner and the like comprising the steps of generating electrical signals in response to reflections of an ultrasonic wave, applying said electrical signals to a variable gain amplifier, storing digital codes indicative of desired gains in a random access memory, selectively addressing said random access memory whereby a variable digital code is obtained, applying said digital code to a digital to analog converter means to thereby derive an analog control signal, and applying said analog control signal to control the gain of said variable gain amplifier.
- 7. In an ultrasonic scanner having a variable gain amplifier for amplifying a time attenuated signal, means for generating a control signal for said variable gain amplifier comprising a first random access digital memory means, means for loading first digital codes indicative of gain in said first random access memory means, digital to analog conversion means, means for selectively addressing said first random access memory whereby a variable digital code is obtained, means for applying said first digital code to said digital to analog converter means and thereby generating an analog signal, and means for applying said analog signal to the variable gain amplifier in time correlation with said time attenuated signal.
Specification