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US3839677A
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US
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Tunable resonant circuits employing ferrimagnetic bodies controlled by common (main) and noncommon (auxiliary) magnetic fields
Assignee: Varian Medical Systems Inc
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Filing: 1973-10-09
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Granted: 1974-10-01
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Expires: 1993-10-09
Abstract
Abstract First and second ferrimagnetic resonator tuned circuits, such as a input filter circuit and local oscillator circuit, have their respective ferrimagnetic resonator bodies disposed in the gap of an common magnet. An auxiliary magnet is provided for producing an offset in the magnetic field intensity within one of the ferrimagnetic resonator bodies relative to the other to produce a difference in the resonant frequencies of the two ferrimagnetic resonator tuned circuits. The magnetic field of the main magnet and, in some cases, the field of the auxiliary magnet as well, are swept in intensity to produce a corresponding sweep in the resonant frequencies of the two ferrimagnetic resonator tuned circuits while maintaining a controlled frequency difference therebetween.
Inventors
- 👤 J Sedin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:00
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/215; H01P1/218; H03; H03B; H03B5/00; H03B5/18; H03B5/1882; H03B5/1888; H03B2201/00; H03B2201/02; H03B2201/0225; H03B2201/0241; H03B23/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
149 words
In a tunable ferrimagnetic resonant circuit, main magnet means comprising a structure having a pair of spaced, opposing poles defining a gap and providing a fixed magnetic field in said gap, first and second ferrimagnetic resonator bodies disposed within said field in said gap, first and second electrical circuit means magnetically coupled to said first and second bodies, respectively, such that the resonant frequencies of said first and second circuit means are determined by said first and second resonator bodies, respectively, means for electrically varying the intensity of said fixed magnetic field applied to both of said bodies for shifting the resonant frequencies of both of said circuit means in the same direction simultaneously, and means for electrically varying the magnetic field intensity applied to one of said resonator bodies relative to the other for shifting the resonant frequency of one of said circuit means relative to the other.
Claim 2
Dependent Claim
149 words
In a tunable ferrimagnetic resonant circuit, main magnet means comprising a structure having a pair of spaced, opposing poles defining a gap and providing a fixed magnetic field in said gap, first and second ferrimagnetic resonator bodies disposed within said field in said gap, first and second electrical circuit means magnetically coupled to said first and second bodies, respectively, such that the resonant frequencies of said first and second circuit means are determined by said first and second resonator bodies, respectively, means for electrically varying the intensity of said fixed magnetic field applied to both of said bodies for shifting the resonant frequencies of both of said circuit means in the same direction simultaneously, and means for electrically varying the magnetic field intensity applied to one of said resonator bodies relative to the other for shifting the resonant frequency of one of said circuit means relative to the other.
Claim 3
Dependent Claim
41 words
The apparatus of claim 1 wherein said means for varying the magnetic field intensity applied to one of said resonator bodies comprises auxiliary electromagnet means for producing and superimposing an auxiliary magnetic field component on the main field in said gap.
Claim 4
Dependent Claim
41 words
The apparatus of claim 2 wherein one of said poles of said main magnet means includes a slot which divides said pole into first and second legs and said auxiliary electromagnetic means includes a coil wound around one of said legs.
Claim 5
Dependent Claim
39 words
The apparatus of claim 2 wherein said main magnet means comprises an electromagnet, and wherein said means for varying the magnetic field intensity includes first sweep generator means for energizing said main means with a current of varying amplitude.
Claim 6
Dependent Claim
61 words
The apparatus of claim 4 wherein said means for varying the magnetic field intensity includes an auxiliary electromagnet and second sweep current generator means for energizing said auxiliary electromagnet, whereby differences in tuning rates between said first and second ferrimagnetic resonator bodies can be compensated by employing different current sweep rates for said first and said second sweep current generator means.
Claim 7
Dependent Claim
72 words
The apparatus of claim 1 wherein said first electrical circuit is a bandpass filter circuit for band limiting a radio frequency input signal, and said second electrical circuit is part of a local oscillator circuit for generating a radio frequency local oscillator signal, and further including mixer means for heterodyning the output signal of said bandpass filter circuit with the output signal of said local oscillator for deriving an intermediate frequency signal.
Claim 8
Dependent Claim
82 words
The apparatus of claim 6 wherein said local oscillator circuit is tunable and further including tunable discriminator means connected to sample the output frequency of said tunable local oscillator circuit for deriving an output indicative of the sense and magnitude of the departuRe of the sampled frequency from the tuned frequency of the said discriminator means, and means responsive to the output of said discriminator means for tuning the frequency of said tunable local oscillator to the frequency of said discriminator means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |