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US3895321A
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Minimum phase differential phase shifter
Assignee: AT&T Inc
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Filing: 1974-08-09
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Granted: 1975-07-15
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Expires: 1994-08-09
Abstract
Abstract A procedure for synthesizing any prescribed differential phase shift by means of passive lumped element, minimum phase networks is outlined. In a first embodiment of the invention, the phase shifters are made of quadrature couplers. In a second embodiment of the invention, bridged-T phase shifters are employed.
Inventors
- 👤 Harold Seidel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:14
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/18; H03H7/21; H03H7/48
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
223 words
A minimum phase network for introducing a differential phase shift Delta Phi (p) between two signals propagating along two different wavepaths including: a first phase shifter located in one of said wavepaths for producing a phase shift Phi 1(p) in one of said signals; a second phase shifter, different from said first, located in the other of said wavepaths for producing a phase shift Phi 2(p) in the other of said signals, where Delta Phi (p) Phi 1(p) - Phi 2(p), and p i omega ; characterized in that: said first and second phase shifters comprise solely passive lumped element circuit components; Delta Phi (p) 2 arctan Im Gamma (p), where Gamma (p) is given as the ratio of an even order polynomial E(p) and an odd order polynomial 0(p); Phi 1(p) 2 arctan Im Gamma 1(p), where Gamma 1(p) is given as the ratio of an even order polynomial E1(p) and an odd order polynomial 01(p); Phi 2(p) 2 arctan Im Gamma 2(p), where Gamma 2(p) is given as the ratio of an even order polynomial E2(p) and an odd order polynomial 02(p); and in that all the roots of the equation E1(p) + 01(p) 0, and the negative of all of the roots of the equation E2(p) + 02(p) 0 are also the roots of the equation E(p) + 0(p) 0.
Claim 2
Dependent Claim
223 words
A minimum phase network for introducing a differential phase shift Delta Phi (p) between two signals propagating along two different wavepaths including: a first phase shifter located in one of said wavepaths for producing a phase shift Phi 1(p) in one of said signals; a second phase shifter, different from said first, located in the other of said wavepaths for producing a phase shift Phi 2(p) in the other of said signals, where Delta Phi (p) Phi 1(p) - Phi 2(p), and p i omega ; characterized in that: said first and second phase shifters comprise solely passive lumped element circuit components; Delta Phi (p) 2 arctan Im Gamma (p), where Gamma (p) is given as the ratio of an even order polynomial E(p) and an odd order polynomial 0(p); Phi 1(p) 2 arctan Im Gamma 1(p), where Gamma 1(p) is given as the ratio of an even order polynomial E1(p) and an odd order polynomial 01(p); Phi 2(p) 2 arctan Im Gamma 2(p), where Gamma 2(p) is given as the ratio of an even order polynomial E2(p) and an odd order polynomial 02(p); and in that all the roots of the equation E1(p) + 01(p) 0, and the negative of all of the roots of the equation E2(p) + 02(p) 0 are also the roots of the equation E(p) + 0(p) 0.
Claim 3
Dependent Claim
63 words
The network according to claim 1 wherein each phase shifter is an all pass network comprising a tandem array of two identical quadrature couplers; wherein Gamma 1(p) is the signal division ratio of each of the quadrature couplers of said first phase shifter; and wherein Gamma 2(p) is the signal division ratio of each of the quadrature couplers of said second phase shifter.
Claim 4
Dependent Claim
64 words
The network according to claim 2 wherein: each quadrature coupler is said first phase shifter comprises a tandem array of quadrature couplers whose roots corresponD to the roots of the equation E1(p) + 01(p) 0; and each quadrature coupler in said second phase shifter comprises a tandem array of quadrature couplers whose roots correspond to the roots of the equation E2(p) + 02(p) 0.
Claim 5
Dependent Claim
180 words
The network according to claim 1 wherein each phase shifter comprises: a tightly coupled two-winding transformer having a 1:1 turns ratio; one end of one transformer winding being connected to one end of the other transformer winding to form a series-aiding connection; a first reactive network connected between the other ends of said series-connected transformer windings thereby forming at one connection a first common junction and at the other connection a second common junction; and a second reactive network, dual to said first, connected between said one ends of said transformer windings and a third common junction; said first and said third common junctions constituting a first port of said phase shifter; said second and said third common junctions constituting a second port of said phase shifter; and wherein the reactance X1 of said first reactive network of said first phase shifter is equal to 2ZoIm Gamma 1(p); and the reactance X2 of said first reactive network of said second phase shifter is equal to 2ZoIm Gamma 2(p); where Zo is the input and output impedance of said phase shifters.
References Cited (Backward Citations)
US2661458A
Cited
US3346823A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |