Abstract: Time gain control of a variable gain amplifier in an ultrasonic scanning system is defined from ultrasonic attenuation of tissue under examination. An ultrasonic signal is directed into the tissue and a reflected signal is detected. The frequency of the reflected signal is measured, and frequency dependent scatter perturbations are identified and eliminated from the measured frequency. Tissue attenuation is then established from the measured frequency after perturbations are eliminated.

Abstract: The characteristics of an ultrasonic scanning system, including band-width, center frequency, and spectrum shape of reflected signals, are determined by directing ultrasonic energy from the system into a phantom having known ultrasonic attenuation and detecting the reflected ultrasonic signal for various depths in the phantom. Band-width is measured from the slope of frequency versus phantom depth. Center frequency is determined from the frequency of the signal reflected from the surface of the phantom. Spectrum shape is determined from the change in frequency of the reflected signal with change in phantom depth.

Abstract: The periodicity of a wave structure is determined by detecting a temporal feature such as zero crossings of the wave, measuring time intervals between zero crossings, and developing a histogram of the time intervals. A periodic structure will exhibit a uniformity in the time intervals, whereas a random signal will have random time intervals between zero crossings.

Abstract: A time gain control (TGC) signal for a variable gain amplifier in an ultrasonic scanner is derived by determining the attenuation at many levels in the object under examination and then constructing the TGC signal based on the cumulative attenuation of an ultrasonic signal through the object. A zero crossing detector such as a Schmitt triggered monostable multivibrator receives a reflected ultrasonic wave signal and generates pulses which are counted during time intervals corresponding to a depth level in the object. By comparing the zero crossing density at one level to the zero crossing density at another level a measure of attenuation between the two levels is obtained.

Abstract: Ultrasonic wave attenuation in an object is determined from the number of zero crossings of a reflected signal as a function of depth. The zero crossing density is indicative of the frequency spectrum, and by comparing the zero crossing density at one level to the zero crossing density at a second level a measure of attenuation therebetween is obtained. Apparatus for implementing the method comprises a zero crossing detector such as a Schmitt triggered monostable multivibrator and a pulse counter.