US4012703A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transmission line pulse transformers
Assignee: US Philips Corp
•
Filing: 1975-11-12
•
Granted: 1977-03-15
•
Expires: 1995-11-12
Abstract
Abstract A transmission line pulse transformer in which the characteristic impedance of a coiled transmission line is changed from a first value to a second (smaller) value at a first point intermediate its ends and back to the first value at a second point. The location of the points and the relationship between the two impedance values are so chosen that, to a first order approximation, reflected waves from the points cancel coupled waves between adjacent turns, thereby reducing distortion caused by the coupled waves.
Inventors
- 👤 John Walter Chamberlayne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:34
CPC Classifications
H; H01; H01F; H01F19/00; H01F19/04; H01F19/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
172 words
A transmission line pulse transformer comprising a bifilar winding formed by at least two turns of each of a pair of conductors, which conductors are maintained at a fixed distance from each other throughout their length, wherein the cross-sectional area of each conductor is increased from a first value to a second value at a first point between one third and two thirds the distance around the first turn of the winding and is decreased from the second value to the first value at a second point between one third and two thirds of the distance around the last turn of the winding; said values being so chosen that the relationship between the characteristic impedance Zo of each of the pair portions having the said first value and the characteristic impedance Zl of the intervening pair portion having said second value is given by: Zl Zo[ (1 - k)/(1 + k) ] where k = Cm/Ci Cm = the mutual capacitance between pair turns, and Ci = the self-capacitance of the pair.
Claim 2
Dependent Claim
172 words
A transmission line pulse transformer comprising a bifilar winding formed by at least two turns of each of a pair of conductors, which conductors are maintained at a fixed distance from each other throughout their length, wherein the cross-sectional area of each conductor is increased from a first value to a second value at a first point between one third and two thirds the distance around the first turn of the winding and is decreased from the second value to the first value at a second point between one third and two thirds of the distance around the last turn of the winding; said values being so chosen that the relationship between the characteristic impedance Zo of each of the pair portions having the said first value and the characteristic impedance Zl of the intervening pair portion having said second value is given by: Zl Zo[ (1 - k)/(1 + k) ] where k = Cm/Ci Cm = the mutual capacitance between pair turns, and Ci = the self-capacitance of the pair.
Claim 3
Dependent Claim
25 words
A transformer according to claim 1 wherein said first and second points are each located substantially half-way round the said first and last turns respectively.
Claim 4
Dependent Claim
15 words
A transformer according to claim 1 wherein the turns surround a core of magnetic material.
Claim 5
Dependent Claim
14 words
A transformer according to claim 3 wherein the said core is a ferrite core.
Claim 6
Dependent Claim
30 words
A transformer according to claim 1, wherein each conductor is formed by printed wiring tracks on a respective face of a printed circuit board, said turns constituting a spiral winding.
Claim 7
Dependent Claim
12 words
A transformer according to claim 5 wherein said board is of fiberglass.
Claim 8
Dependent Claim
71 words
A transformer according to claim 1, wherein each conductor is formed as first and second spiral windings in series, the two first windings being formed by printed wiring tracks on respective faces of a first printed circuit board and the two second windings being formed by printed wiring tracks on respective faces of a second printed circuit board, and wherein the two boards are in parallel spaced relationship with each other.
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) | 1980-03-14 | 1980-09-13 | 1981-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-14 | 1984-09-13 | 1985-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-14 | 1988-09-13 | 1989-03-15 | $7700.00 | Window Closed / Lapsed |