US3715690A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic tuning electric wave filter
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1971-05-18
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Granted: 1973-02-06
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Expires: 1991-05-18
Abstract
Abstract A band pass filter for use in RF transmitting or receiving apparatus comprises a plurality of resonant stages coupled through variable apertures whose areas are dependent on the tuning adjustment of the resonant stages whereby a substantially constant bandwidth and insertion loss are achieved over the tuning range. Tuning is effected by a servomechanism responsive to the conditions of phase and signal level at the input and output ports of the filter. The phase and signal level are sensed through directional couplers at the input and output ports of the filter. The couplers at the filter input and output act as matching sections, thereby minimizing losses.
Inventors
- 👤 R Young
- 👤 F Radler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:22
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/0123; H01; H01P; H01P1/00; H01P1/20; H01P1/207; H01P1/208; H01P7/00; H01P7/08; H01P7/088; H03H7/0153; H03H7/0161; H03H7/17; H03H7/1741; H03H7/1775
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
115 words
An electric wave filter comprising: a plurality of resonant stages each passing signals at or near a desired resonant frequency, but attenuating signals at other frequencies, tuning means for each of said resonant stages, said tuning means being interconnected and synchronized so that all of said resonant stages are tuned simultaneously to substantially the same resonant frequency, means electrically coupling said resonant stages to provide a multiple-stage filter, said coupling means being adjustable, and means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the resonant frequency of said stages increases, the coupling between said stages decreases to an extent providing a substantially constant bandwidth over the tuning range.
Claim 2
Dependent Claim
115 words
An electric wave filter comprising: a plurality of resonant stages each passing signals at or near a desired resonant frequency, but attenuating signals at other frequencies, tuning means for each of said resonant stages, said tuning means being interconnected and synchronized so that all of said resonant stages are tuned simultaneously to substantially the same resonant frequency, means electrically coupling said resonant stages to provide a multiple-stage filter, said coupling means being adjustable, and means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the resonant frequency of said stages increases, the coupling between said stages decreases to an extent providing a substantially constant bandwidth over the tuning range.
Claim 3
Dependent Claim
115 words
An electric wave filter comprising: a plurality of resonant stages each passing signals at or near a desired resonant frequency, but attenuating signals at other frequencies, tuning means for each of said resonant stages, said tuning means being interconnected and synchronized so that all of said resonant stages are tuned simultaneously to substantially the same resonant frequency, means electrically coupling said resonant stages to provide a multiple-stage filter, said coupling means being adjustable, and means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the resonant frequency of said stages increases, the coupling between said stages decreases to an extent providing a substantially constant bandwidth over the tuning range.
Claim 4
Dependent Claim
115 words
An electric wave filter comprising: a plurality of resonant stages each passing signals at or near a desired resonant frequency, but attenuating signals at other frequencies, tuning means for each of said resonant stages, said tuning means being interconnected and synchronized so that all of said resonant stages are tuned simultaneously to substantially the same resonant frequency, means electrically coupling said resonant stages to provide a multiple-stage filter, said coupling means being adjustable, and means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the resonant frequency of said stages increases, the coupling between said stages decreases to an extent providing a substantially constant bandwidth over the tuning range.
Claim 5
Dependent Claim
85 words
An electric wave filter comprising: a plurality of resonant stages, means coupling said resonant stages to provide a multiple-stage band-pass filter, said coupling means being adjustable, means for tuning said multiple-stage band-pass filter to adjust its center frequency through a tuning range, and means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the center frequency of said pass band inCreases, the coupling between said stages decreases to an extent providing a substantially constant bandwidth over the tuning range.
Claim 6
Dependent Claim
85 words
An electric wave filter comprising: a plurality of resonant stages, means coupling said resonant stages to provide a multiple-stage band-pass filter, said coupling means being adjustable, means for tuning said multiple-stage band-pass filter to adjust its center frequency through a tuning range, and means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the center frequency of said pass band inCreases, the coupling between said stages decreases to an extent providing a substantially constant bandwidth over the tuning range.
Claim 7
Dependent Claim
86 words
An electric wave filter comprising: a plurality of resonant stages, means coupling said resonant stages to provide a multiple-stage band-pass filter, said coupling means being adjustable, means for tuning said multiple-stage band-pass filter to adjust its center frequency through a tuning range, and means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the center frequency of said pass band increases, the coupling between said stages decreases, thereby providing a reduction in the variation of bandwidth over the tuning range.
Claim 8
Dependent Claim
86 words
An electric wave filter comprising: a plurality of resonant stages, means coupling said resonant stages to provide a multiple-stage band-pass filter, said coupling means being adjustable, means for tuning said multiple-stage band-pass filter to adjust its center frequency through a tuning range, and means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the center frequency of said pass band increases, the coupling between said stages decreases, thereby providing a reduction in the variation of bandwidth over the tuning range.
Claim 9
Dependent Claim
45 words
An electric wave filter according to claim 3, in which said resonant stages are cavities, each adjustable by said tuning means and in which said coupling means comprises means providing variable interstage apertures adjustable by said means responsive to the condition of said tuning means.
Claim 10
Dependent Claim
82 words
An electric wave filter according to claim 3, in which said resonant stages are cavities, each containing an inductor and a variable capacitor connected in shunt with said inductor; each said capacitor being adjustable by said tuning means; and in which said coupling means comprises means providing inter-stage apertures including door means for each of said apertures operated by said means responsive to the condition of said tuning means to adjust the areas of the apertures as said tuning means is adjusted.
Claim 11
Dependent Claim
83 words
An electric wave filter according to claim 3, in which said resonant stages are cavities, each containing an inductor and a variable capacitor connected in shunt with said inductor; in which the variable capacitors are connected to be adjusted through a common rotatable shaft by said tuning means; and in which said coupling means comprises means providing inter-stage apertures including door means for each of said apertures operated by said shaft to adjust the areas of the apertures as said shaft is rotated.
Claim 12
Dependent Claim
23 words
An electric wave filter according to claim 3, in which said means for tuning said multiple-stage band-pass filter comprises mechanically adjustable resonant means.
Claim 13
Dependent Claim
102 words
An electric wave filter according to claim 3 in which the means for tuning the filter comprises a motor, and means responsive to the phase shift across the filter for controlling the motor whereby the motor comes to a stop when the phase shift corresponds to the tuning of the center frequency of the filter pass-band to the frequency of the signal at the filter input, said means responsive to the phase shift across the filter including means compensating for variations in the phase shift across the filter at resonance which are dependent on the frequency to which the filter is tuned.
Claim 14
Dependent Claim
67 words
An electric wave filter according to claim 8 in which the means responsive to the phase shift across the filter comprises phase-sensitive detecting means coupled to the input and output of the filter and producing an output which varies in accordance with the phase shift across the filter and in which the compensation means comprises a delay line connected between the detecting means and the filter input.
Claim 15
Dependent Claim
135 words
An electric wave filter comprising: a plurality of resonant stages, means coupling said resonant stages to provide a multiple-stage band-pass filter, said coupling means being adjustable, means for tuning said multiple-stage band-pass filter to adjust its center frequency through a tuning range, means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the center frequency of said pass band increases, the coupling between said stages decreases, thereby providing a reduction in the variation of bandwidth over the tuning range, and means responsive to the signals at the input and output of said filter for effecting operation of said tuning means whereby said tuning means is adjusted to a condition in which the cEnter frequency of the filter pass-band corresponds to the frequency of the signal at the filter input.
Claim 16
Dependent Claim
135 words
An electric wave filter comprising: a plurality of resonant stages, means coupling said resonant stages to provide a multiple-stage band-pass filter, said coupling means being adjustable, means for tuning said multiple-stage band-pass filter to adjust its center frequency through a tuning range, means responsive to the condition of said tuning means for adjusting said coupling means whereby, as the center frequency of said pass band increases, the coupling between said stages decreases, thereby providing a reduction in the variation of bandwidth over the tuning range, and means responsive to the signals at the input and output of said filter for effecting operation of said tuning means whereby said tuning means is adjusted to a condition in which the cEnter frequency of the filter pass-band corresponds to the frequency of the signal at the filter input.
Claim 17
Dependent Claim
121 words
In combination: a band-pass filter having an input and an output, and having an adjustable pass band center frequency, and means for adjusting the pass band center frequency, said adjusting means comprising a motor, and means responsive to the phase shift across said filter for controlling said motor whereby said motor comes to a stop when said phase shift across the filter corresponds to tuning of the center frequency of the filter pass band to the frequency of the signal of the filter input, said means responsive to the phase shift across the filter including means compensating for variations in the phase shift across the filter at resonance which are dependent on the center frequency to which the filter is tuned.
Claim 18
Dependent Claim
121 words
In combination: a band-pass filter having an input and an output, and having an adjustable pass band center frequency, and means for adjusting the pass band center frequency, said adjusting means comprising a motor, and means responsive to the phase shift across said filter for controlling said motor whereby said motor comes to a stop when said phase shift across the filter corresponds to tuning of the center frequency of the filter pass band to the frequency of the signal of the filter input, said means responsive to the phase shift across the filter including means compensating for variations in the phase shift across the filter at resonance which are dependent on the center frequency to which the filter is tuned.
Claim 19
Dependent Claim
66 words
The combination according to claim 11 in which said means responsive to the phase shift across said filter comprises phase-sensitive detecting means coupled to said input and said output and producing an output which varies in accordance with the phase shift across the filter and in which said compensating means comprises a delay line connected between said phase-sensitive detecting means and the input of said filter.
Claim 20
Dependent Claim
121 words
In combination: a band-pass filter having an input and an output and having an adjustable pass band center frequency, means for sensing a peak in the transmission of power by said filter from said input to said output comprising means for sensing a decrease in reflected power at the input of said filter and a simultaneous increase in transmitted power at the output of said filter, and means for adjusting the pass-band center frequency of the filter, said adjusting means comprising a motor, means operating said motor for scanning the tuning range and means responsive to said sensing means for bringing said motor to a stop when the sensing means senses a peak in the transmission of power by said filter.
Claim 21
Dependent Claim
121 words
In combination: a band-pass filter having an input and an output and having an adjustable pass band center frequency, means for sensing a peak in the transmission of power by said filter from said input to said output comprising means for sensing a decrease in reflected power at the input of said filter and a simultaneous increase in transmitted power at the output of said filter, and means for adjusting the pass-band center frequency of the filter, said adjusting means comprising a motor, means operating said motor for scanning the tuning range and means responsive to said sensing means for bringing said motor to a stop when the sensing means senses a peak in the transmission of power by said filter.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |