US3760301A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switchable band-pass filter having resonant circuit energized inductively from constant current source
Assignee: SONAB DEV AB
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Filing: 1972-12-05
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Granted: 1973-09-18
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Expires: 1992-12-05
Abstract
Abstract A band-pass filter device, which can be switched selectively between several different frequencies, comprises a parallel resonance circuit containing a capacitance and a coil provided with several taps and switching means connected to the taps on the coil for inserting selectively and alternatively differently large portions of the coil into the resonance circuit. The resonance circuit is energized inductively from a constant current source through the coil of the resonance circuit. The input signal to the filter is applied as a control signal to the constant current source and the output on the filter device is connected across the resonance circuit.
Inventors
- 👤 K Goransson
- 👤 J Dahlgren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:42
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/01; H03H7/0153; H03H7/0161
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
108 words
A band-pass filter device comprising a parallel resonance circuit devoid of discrete resistances and including a capacitor and a coil provided with a plurality of taps, switching means cooperating with said taps for inserting selectively and alternatively differently large portions of said coil in said parallel resonance circuit, a constant current source controlled by the input signal supplied to the filter device for feeding said parallel resonance circuit inductively through said coil, and an output load connected across said resonance circuit for receiving the output signal from the filter device, said output load having a large impedance as compared to the impedance at resonance of said resonance circuit.
Claim 2
Dependent Claim
108 words
A band-pass filter device comprising a parallel resonance circuit devoid of discrete resistances and including a capacitor and a coil provided with a plurality of taps, switching means cooperating with said taps for inserting selectively and alternatively differently large portions of said coil in said parallel resonance circuit, a constant current source controlled by the input signal supplied to the filter device for feeding said parallel resonance circuit inductively through said coil, and an output load connected across said resonance circuit for receiving the output signal from the filter device, said output load having a large impedance as compared to the impedance at resonance of said resonance circuit.
Claim 3
Dependent Claim
42 words
A band-pass filter device as claimed in claim 1, wherein said constant current source includes an amplifier transistor having a base for receiving said input signal and a collector circuit including a winding coupled inductively to Said coil of said resonance circuit.
Claim 4
Dependent Claim
52 words
A band-pass filter device as claimed in claim 1, wherein said switching means include at least two switch transistors having their collectors connected separately to one each of said taps on said coil of said resonance circuit and their emitters jointly connected to one side of said capacitor of the resonance circuit.
Claim 5
Dependent Claim
53 words
A band-pass filter device as claimed in claim 1, wherein said coil in said resonance circuit has an internal resistance between any one of said taps and one end terminal of the coil which is substantially directly proportional to the number of turns of the coil between said tap and said end terminal.
References Cited (Backward Citations)
US2761066A
Cited
US3427569A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |