US3922911A
Expired / Lapsed
US
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Apparatus and method of determining flow
Assignee: Hawker Siddeley Dynamics Ltd
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Filing: 1972-11-27
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Granted: 1975-12-02
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Expires: 1992-11-27
Abstract
Abstract In determination of the characteristics of fluid flow in a conduit, such as blood flow in a blood vessel, the signal information received from a Doppler flow-meter, in the form of a multiplicity of different frequencies simultaneously present, is filtered to give the different frequency signals on separate parallel channels and then the channels are cyclically sampled in sequence. The signal samples so obtained appear in ordered series on a common signal line and may be used to generate a C.R.T. visual display in which each frequency forms an individual trace the consecutive traces being separated from one another by small increments in the Y-axis direction of the display. The different frequency signals are also mutually time separated by comparatively small increments in the X-axis direction, thereby giving a pictorial, apparently three-dimensional, display pattern looking rather like a carpet with humps in it.
Inventors
- 👤 Henry William Groves
- 👤 John Yarnell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 18:40
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/66; G01F1/663; A; A61; A61B; A61B8/00; A61B8/06; G01N; G01N2291/00; G01N2291/02; G01N2291/028; G01N2291/02836
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
262 words
In the determination of flow characteristics of a fluid in a flow path by the Doppler flow sensing technique, which technique derives a plurality of measurement signals of different nominal frequency and shifted in frequency from said nominal frequency as a function of the instantaneous velocity of respective fluid particles in said flow path, a method of processing said signals comprising the steps of: separating said measurement signals, one from the other, on the basis of nominal frequency; cyclically obtaining amplitude samples from the separated signals in turn in a predetermineD sequence which is repeated at a sufficiently high rate to respond to significant changes in the power level in each such signal; combining the obtained amplitude samples, in the order obtained, in a common signal channel for further processing; and providing a two-axis graphical display in the form of a plurality of traces, each trace corresponding to a respective measurement signal as reconstructed from successive amplitude samples obtained from that signal, wherein the different traces appear simultaneously in a band of nominally parallel traces extending along one axis representing time, the traces being separated in the band along the other axis of the display and ordered according to the sequence in which their amplitude samples appear, said other axis representing amplitude for each trace individually wherein all of the traces in said band are mutually time-shifted in such manner that each succeeding trace in the band has an equal time shift in the same direction from the immediately preceding trace, whereby a pictorial and illusionary three-dimensional carpet-like display pattern is developed.
Claim 2
Dependent Claim
262 words
In the determination of flow characteristics of a fluid in a flow path by the Doppler flow sensing technique, which technique derives a plurality of measurement signals of different nominal frequency and shifted in frequency from said nominal frequency as a function of the instantaneous velocity of respective fluid particles in said flow path, a method of processing said signals comprising the steps of: separating said measurement signals, one from the other, on the basis of nominal frequency; cyclically obtaining amplitude samples from the separated signals in turn in a predetermineD sequence which is repeated at a sufficiently high rate to respond to significant changes in the power level in each such signal; combining the obtained amplitude samples, in the order obtained, in a common signal channel for further processing; and providing a two-axis graphical display in the form of a plurality of traces, each trace corresponding to a respective measurement signal as reconstructed from successive amplitude samples obtained from that signal, wherein the different traces appear simultaneously in a band of nominally parallel traces extending along one axis representing time, the traces being separated in the band along the other axis of the display and ordered according to the sequence in which their amplitude samples appear, said other axis representing amplitude for each trace individually wherein all of the traces in said band are mutually time-shifted in such manner that each succeeding trace in the band has an equal time shift in the same direction from the immediately preceding trace, whereby a pictorial and illusionary three-dimensional carpet-like display pattern is developed.
Claim 3
Dependent Claim
20 words
The method according to claim 1 wherein said two-axis graphical display is presented on a long-persistence cathode ray oscilloscope tube.
Claim 4
Dependent Claim
24 words
The method according to claim 2 further comprising the step of periodically brightening the cathode ray at regular intervals of display along both axes.
Claim 5
Dependent Claim
90 words
The method according to claim 1 wherein said traces are displayed according to the equations: y k1Vn + q(Vn,t) and x k2t, wherein x is the position along said one axis and y is the position along said other axis, k1 and k2 are constants, Vn is the instantaneous fluid particle velocity represented by measurement signal n, n represents the number of each measurement signal in turn, t represents time, and q (Vn, t) represents a function of Vn and t determined by parameters of the Doppler flow sensing technique.
Claim 6
Dependent Claim
88 words
The method according to claim 1 wherein said traces are displayed according to the equations: y k1Vn and x k2t -q(Vn,t), wherein x is the position along said one axis and y is the position along said other axis, k1 and k2 are constants, Vn is the instantaneous fluid particle velocity represented by measurement signal n, n represents the number of each measurement signal in turn, t represents time, and q (Vn,t) represents a function of Vn and t determined by parameters of the Doppler flow sensing technique.
Claim 7
Dependent Claim
97 words
The method according to claim 1 wherein said traces are displayed according to the equations: y k1Vn + q(Vn,t) cos Theta and x k2t - q(Vn,t) sin Theta , wherein x is the position along said one axis and y is the position along said other axis, Theta , k1 and k2 are constants, Vn is the instantaneous fluid particle velocity represented by measurement signal n, n represents the number of each measurement signal in turn, t represents time, and q(Vn,t) represents a function of Vn and t determined by parameters of the Doppler flow sensing technique.
Claim 8
Dependent Claim
91 words
The method according to claim 1 wherein said traces are displayed according to the equations: y k1Vn + q(Vn,t) and x k2t + k3Vn wherein x is the position along said one axis and y is the position along said other axis, k1, k2 and k3 are constants, Vn is the instantaneous fluid particle velocity repreSented by measurement signal n, n represents the number of each measurement signal in turn, t represents time, and q(Vn,t) represents a function of Vn and t determined by parameters of the Doppler flow sensing technique.
Claim 9
Dependent Claim
42 words
The method according to claim 1, wherein said display is presented on a cathode ray tube, said method further comprising the step of reducing the brightness of the cathode ray when the amplitude sample to be displayed is below a predetermined level.
Claim 10
Dependent Claim
29 words
The method according to claim 1 further comprising the step of inhibiting display of amplitude samples for any trace in which the amplitude samples are below a predetermined level.
Claim 11
Dependent Claim
14 words
The method according to claim 1 employed to determine blood flow characters in vivo.
Claim 12
Dependent Claim
133 words
Apparatus for processing measurement signals obtained by the Doppler flow sensing technique, wherein said measurement signals are of different nominal frequencies from which the signals are shifted as a function of the instantaneous velocity of respective fluid particles in the sensed flow, said apparatus comprising: a clock pulse source; automatically re-cycling counter means for counting clock pulses from said source and defining operating cycles of said apparatus; a multiplexer controlled by said counter means and arranged to receive a plurality of input signals to which individual numbers are assigned and provide as a single output signal the input signal having an assigned number corresponding to the clock pulse count at said counter means; and means for applying said measurement signals of different nominal frequency to said mulitplexer as said plurality of input signals.
Claim 13
Dependent Claim
133 words
Apparatus for processing measurement signals obtained by the Doppler flow sensing technique, wherein said measurement signals are of different nominal frequencies from which the signals are shifted as a function of the instantaneous velocity of respective fluid particles in the sensed flow, said apparatus comprising: a clock pulse source; automatically re-cycling counter means for counting clock pulses from said source and defining operating cycles of said apparatus; a multiplexer controlled by said counter means and arranged to receive a plurality of input signals to which individual numbers are assigned and provide as a single output signal the input signal having an assigned number corresponding to the clock pulse count at said counter means; and means for applying said measurement signals of different nominal frequency to said mulitplexer as said plurality of input signals.
Claim 14
Dependent Claim
118 words
The apparatus according to claim 11 further comprising: two-axis display means having an x-axis amplifier, a y-axis amplifier, a visual display member on which indicia appears as a function of the amplitudes of signals applied to said x-axis and y-axis amplifiers; a first ramp generator for providing a first ramp waveform signal; means for summing the output signal from said multiplexer with said first ramp waveform signal to provide a sum signal; means for applying said sum signal to said y-axis amplifier; control means for controlling the intensity of indicia on said visual display; and means for pulsing said control means and said ramp generator means each time the count in said control means reaches a predetermined number.
Claim 15
Dependent Claim
106 words
The apparatus according to claim 12 further comprising: sine-cosine resolver means responsive to signal applied thereto for providing a first output signal of amplitude equal to the input signal amplitude multiplied by the sine of a predetermined angle and a second output signal of amplitude equal to the input signal amplitude multiplied by the cosine of said predetermined angle; means for applying the output signal from said multiplexer to said sine-cosine resolver means; means for applying said first output signal from said sine-cosine resolver means to said x-axis amplifier; and means for applying said second output signal from said sine-cosine rresolver means to said y-axis amplifier.
Claim 16
Dependent Claim
145 words
Apparatus for processing measurement signals obtained by the Doppler flow sensing technique, wherein said measurement signals are of different nominal frequencies from which the signals are shifted as a function of the instantaneous velocity of respective fluid particles in the sensed flow, said apparatus comprising: clocking means for generating a train of pulses defining repetitive sequences of operating cycles of said apparatus; a multiplexer controlled by said clocking means and arranged to receive a plurality of input signals to which individual members are assigned, each number corresponding to a respective operating cycle defined by said train of pulses, and to provide as a single output signal the input signal having an assigned number corresponding to the current operative cYcle defined by said train of pulses; and means for applying said measurement signals of different nominal frequency to said multiplexer as said plurality of input signals.
Claim 17
Dependent Claim
145 words
Apparatus for processing measurement signals obtained by the Doppler flow sensing technique, wherein said measurement signals are of different nominal frequencies from which the signals are shifted as a function of the instantaneous velocity of respective fluid particles in the sensed flow, said apparatus comprising: clocking means for generating a train of pulses defining repetitive sequences of operating cycles of said apparatus; a multiplexer controlled by said clocking means and arranged to receive a plurality of input signals to which individual members are assigned, each number corresponding to a respective operating cycle defined by said train of pulses, and to provide as a single output signal the input signal having an assigned number corresponding to the current operative cYcle defined by said train of pulses; and means for applying said measurement signals of different nominal frequency to said multiplexer as said plurality of input signals.
Claim 18
Dependent Claim
92 words
The apparatus according to claim 14 further comprising: integrator means for integrating the output signal from said mulitplexer; a high gain amplifier having input and output terminals; source means for providing a constant amplitude signal; a squaring circuit having an input signal connected to the output terminal of said amplifier and having an output terminal; means for connecting the integrated signal from said integrator means to the input terminal of said amplifier in summing relationship with said constant amplitude signal and a feedback signal from the output terminal of said squaring circuit.
Claim 19
Dependent Claim
77 words
The apparatus according to claim 15 further comprising: two-axis display means having x-axis deflection means, y-axis deflection means, and a visual display member on which indicia appears as a function of the amplitudes of signals applied to said x-axis and y-axis deflection means; means for connecting the output terminal of said high-grain amplifier to supply input signal to said y-axis amplifier; and means for synchronizing said x-axis deflection means with a signal derived from said clocking means.
Claim 20
Dependent Claim
52 words
The apparatus according to claim 14 further comprising: a plurality of series input resistors connected to pass and correspondingly scale the measurement signals applied to said multiplexer; resettable integrator means for integrating the output signal from said multiplexer; and means for resetting said integrator upon each of said sequence of operating cycles.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |