US4883060A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for eliminating fixed echoes for an ultrasonic echograph
Assignee: US Philips Corp
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Filing: 1988-07-06
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Granted: 1989-11-28
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Expires: 2008-07-06
Abstract
Abstract A device for eliminating fixed echoes for an ultrasonic echograph, comprising a first filter (100) which consists on the one hand of M parallel lines i (i=1, . . . , M) which a respective delay (i-1)T, where T is the repetition period of the echograph, and on the other hand of weighting means (101i) for the M lines i, the sum of the coefficients (a i ) applied to said lines being zero and, of an adder (102) for the lines i thus delayed and weighted. In accordance with the invention, at least one second filter (200) which has the same structure as and which is dephased by (M-1)T with respect to the first filter (100) is connected parallel to the first filter (100), the pulse response (h 2 (t)) of the second filter being linked to the pulse response (h 1 (t)) of the first filter as: h.sub.2 (t)=h.sub.1 (m-1)T-t). Application: Measurement and imaging of blood flow speeds by ultrasonic echography.
Inventors
- 👤 Patrick R. Pesque
- 👤 Odile M. A. Bonnefous
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:23
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/02; G01S15/50; G01S15/52; H; H03; H03H; H03H15/00; H03H17/00; H03H17/02; H03H17/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
156 words
In an ultrasonic echograph having a pulse repetition period, T, a circuit for eliminating echo signals which represent fixed objects from a stream of echo signals, comprising: first and second filters, each of said filters including: M parallel lines connected to apply respective delays (i-1)T, where i=1, . . . M, to the stream of echo signals; an adder; and M weighting means, each of the weighting means applying signals from a corresponding line to an input of the adder with a respective weighting coefficient a i : and means which combine outputs of the first and second filters; wherein, in each filter the sum of the weighting factors of the M weighting means is zero; the phase response of the second filter shifted by (M-1)T with respect to the first filter; and the impulse response of the second filter is h.sub.2 (t)=h.sub.1 ((M-1)T-t) where h 1 (t) is the impulse response of the first filter.
Claim 2
Dependent Claim
156 words
In an ultrasonic echograph having a pulse repetition period, T, a circuit for eliminating echo signals which represent fixed objects from a stream of echo signals, comprising: first and second filters, each of said filters including: M parallel lines connected to apply respective delays (i-1)T, where i=1, . . . M, to the stream of echo signals; an adder; and M weighting means, each of the weighting means applying signals from a corresponding line to an input of the adder with a respective weighting coefficient a i : and means which combine outputs of the first and second filters; wherein, in each filter the sum of the weighting factors of the M weighting means is zero; the phase response of the second filter shifted by (M-1)T with respect to the first filter; and the impulse response of the second filter is h.sub.2 (t)=h.sub.1 ((M-1)T-t) where h 1 (t) is the impulse response of the first filter.
Claim 3
Dependent Claim
49 words
The circuit of claim 1 wherein the means which combine comprise: first and second velocity determining circuits respectively connected to receive signal outputs from the adders of the first and second filters; and an accumulator connected to receive and accumulate outputs of the first and second velocity determining circuits.
Claim 4
Dependent Claim
12 words
The circuit of claim 2 wherein the velocity determining circuits comprise correlators.
Claim 5
Dependent Claim
13 words
The circuit of claim 2 wherein the velocity determining circuits comprise phase shifters.
Claim 6
Dependent Claim
48 words
The circuit of claim 1 wherein M=3, the weighting means have respective weighting coefficients a 1 =-1/2, a 2 =1, and a 3 =1/2 and the impulse responses of the first and second filters are respectively h.sub.1 (t)=δ(t)-1/2δ(t-T)-1/2δ(t-2T) and h.sub.2 (t)=-1/2δ(t)-1/2δ(t-T)+δ(t-2T) where δ is the Dirac impulse function.
References Cited (Backward Citations)
US4803990A
Cited
US4751847A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-27 | 1993-05-29 | 1993-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-27 | 1997-05-29 | 1997-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-27 | 2001-05-29 | 2001-11-28 | $7700.00 | Window Closed / Lapsed |