Echoscope for examination of objects
First Claim
1. In an echoscope for examination of objects with the aid of an ultrasound beam, comprising at least one electro-acoustic element for transmitting and receiving ultrasonic pulses during a transmission-reception period;
- an amplifier with time-dependent gain control co-operating with the electro-acoustic element for amplifying the echo signals supplied by said element;
a control voltage generator connected to said amplifier for supplying a control voltage thereto to determine the signal gain as a function of time;
adjusting means in said control voltage generator for permitting changing the magnitude of the control voltage as a function of time in n consecutive time intervals of the transmission-reception period, which are bounded by the interval points of time t0, t1, t2 . . . , ti, tj, tk, . . . , tn-1, tn ; and
a display connected to the echo signal amplifier for the visual display of the echo signals received during each transmission-reception period, the improvement of the control voltage generator comprisinga. at least two adjustable voltage sources, each of which cooperates with the adjusting means for arbitrarily setting the voltages (ei, ej) of said sources prevailing at the corresponding interval points of time (ti and tj respectively) between a minimum and a maximum value;
b. at least one differential amplifier co-operating with the adjustable voltage sources for providing a difference voltage (aj ·
ej -bj ·
ei) during a time interval ti to tj, aj and bj being multiplication factors representing a possible attenuation or amplification of the voltages (ei, ej) before their being supplied to the differential amplifier;
c. integrator means for supplying the control voltage to the echo signal amplifier, said integrator means co-operating with the differential amplifier to integrate the difference voltage (aj ·
ej -bj ·
ei) during the respective time interval (ti to tj) with an integrator time constant (RC)j ; and
d. switching means co-operating with said integrator means for successively integrating the difference voltages (aj ·
ej -bj ·
ei) during consecutive time intervals (tj -ti), said time intervals (tj -ti) corresponding to the respective integrator time constants (RC)j according to the relation ##EQU37## with i=0, 1, 2, . . . , n-1 j= i+ 1, and k=j+1, but k≦
n.
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Accused Products
Abstract
An echoscope for examination of objects with the aid of an ultrasound beam, comprising at least one electro-acoustic element for transmitting and receiving ultrasonic pulses during a transmission-reception period divided into n consecutive time intervals. The ultrasonic pulses are sent to the objects to be examined and are reflected therefrom. The echo signals supplied by the receiving element are amplified by an amplifier with time-dependent gain control. The gain control is brought about by a control voltage generator which supplies a control voltage to said amplifier for determining its signal gain as a function of time. Adjusting means for the control voltage generator are provided to make it possible to change the magnitude of the control voltage in the time intervals as a function of time. The apparatus also comprises a device for visually displaying the echo signals received during each transmission-reception period.
35 Citations
31 Claims
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1. In an echoscope for examination of objects with the aid of an ultrasound beam, comprising at least one electro-acoustic element for transmitting and receiving ultrasonic pulses during a transmission-reception period;
- an amplifier with time-dependent gain control co-operating with the electro-acoustic element for amplifying the echo signals supplied by said element;
a control voltage generator connected to said amplifier for supplying a control voltage thereto to determine the signal gain as a function of time;
adjusting means in said control voltage generator for permitting changing the magnitude of the control voltage as a function of time in n consecutive time intervals of the transmission-reception period, which are bounded by the interval points of time t0, t1, t2 . . . , ti, tj, tk, . . . , tn-1, tn ; and
a display connected to the echo signal amplifier for the visual display of the echo signals received during each transmission-reception period, the improvement of the control voltage generator comprisinga. at least two adjustable voltage sources, each of which cooperates with the adjusting means for arbitrarily setting the voltages (ei, ej) of said sources prevailing at the corresponding interval points of time (ti and tj respectively) between a minimum and a maximum value; b. at least one differential amplifier co-operating with the adjustable voltage sources for providing a difference voltage (aj ·
ej -bj ·
ei) during a time interval ti to tj, aj and bj being multiplication factors representing a possible attenuation or amplification of the voltages (ei, ej) before their being supplied to the differential amplifier;c. integrator means for supplying the control voltage to the echo signal amplifier, said integrator means co-operating with the differential amplifier to integrate the difference voltage (aj ·
ej -bj ·
ei) during the respective time interval (ti to tj) with an integrator time constant (RC)j ; andd. switching means co-operating with said integrator means for successively integrating the difference voltages (aj ·
ej -bj ·
ei) during consecutive time intervals (tj -ti), said time intervals (tj -ti) corresponding to the respective integrator time constants (RC)j according to the relation ##EQU37## with i=0, 1, 2, . . . , n-1 j= i+ 1, and k=j+1, but k≦
n. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
- an amplifier with time-dependent gain control co-operating with the electro-acoustic element for amplifying the echo signals supplied by said element;
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18. In an echoscope for examination of parts inside a human body with the aid of ultrasonic pulses, comprising an ultrasonic transducer to be externally placed on the body of a patient;
- a number of electro-acoustic elements supported in said transducer for transmitting and receiving ultrasonic pulses during each transmission-reception period into and from the body, respectively, said transmitting elements having parallel axes of radiation lying in a plane adapted to intersect the body part being examined along a predetermined cross-section;
an amplifier with time-dependent gain control cooperating with the electro-acoustic elements for amplifying the echo signals supplied by the receiving elements;
a control voltage generator connected to said amplifier for supplying a control voltage thereto to determine the signal gain as a function of time;
adjusting means in said control voltage generator for permitting changing the magnitude of the control voltage as a function of time in n consecutive time intervals of the transmission-reception period, which are bounded by the interval points of time t0, t1, t2, . . . , ti, tj, tk, . . . , tn- 1, tn ;
a cathode ray tube including a screen co-operating with the echo signal amplifier;
means for displaying echo signals reflected by parts of the body at the predetermined cross-section and received by said elements on the screen of said cathode ray tube in a cartesian coordinate system wherein one coordinate represents the position of the transmitted ultrasound beam, and another coordinate represents the time of reception of said echo signals; and
means for repeatedly exciting said electro-acoustic elements at such a repetition frequency that an instantaneous image of said cross-section is displayed on the screen of said cathode ray tube, the improvement of the control voltage generator being provided with (a) at least two adjustable voltage sources, each of which cooperates with one of the adjusting means for arbitrarily setting the voltages (ei, ej) of said sources prevailing at the corresponding interval points of time (ti and tj respectively) between a minimum and a maximum value;
(b) at least one differential amplifier co-operating with the adjustable voltage sources for providing a difference voltage (aj ·
ej ·
-bj ·
ei) during a time interval ti to tj, aj and bj being multiplication factors representing a possible attenuation or amplification of the voltages (ei, ej) before their being supplied to the differential amplifier;
(c) integrator means for supplying the control voltage to the echo signal amplifier, said integrator means cooperating with the differential amplifier to integrate the difference voltage (aj ej -bj ei) during the respective time interval (ti to tj) with an integrator time constant (RC)j ; and
(d) switching means cooperating with said integrator means for successively integrating the difference voltages (aj ej -bj ei) during consecutive time intervals (tj -ti), said time intervals (tj -ti) corresponding to the respective integrator time constant (RC)j according to the relation ##EQU40## with i=0, 1, 2, 3, . . . , n-1;
j= i + 1 and k = j+1 but k ≦
n. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
- a number of electro-acoustic elements supported in said transducer for transmitting and receiving ultrasonic pulses during each transmission-reception period into and from the body, respectively, said transmitting elements having parallel axes of radiation lying in a plane adapted to intersect the body part being examined along a predetermined cross-section;
Specification