US3612773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic frequency switching circuit for multifrequency signal generator
Assignee: AT&T Inc
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Filing: 1969-07-22
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Granted: 1971-10-12
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Expires: 1989-07-22
Abstract
Abstract Signal frequency combinations in a multifrequency signal generator are produced selectively by establishing conductive paths through switched insulated-gate field-effect transistors (IGFETS) to connect respective frequency determining elements into the oscillator circuits.
Inventors
- 👤 Charles E Riehm Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:46
CPC Classifications
H; H03; H03B; H03B5/00; H03B5/20; H03B5/24; H04; H04M; H04M1/00; H04M1/26; H04M1/30; H04M1/50; H03B2201/00; H03B2201/02; H03B2201/0275; H03B2201/0283
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
118 words
Apparatus in accordance with claim 1 wherein each of said gate voltage-generating circuits comprises, in combination, first and second input points connectable respectively to said tip and ring terminals means including an IGFET for discharging an associated one of said IGFET switches whenever the corresponding one of said mechanical switches is open, means including a first diode operating as a low capacitance rectifier connected between said first input point and the gate electrode of said last named IGFET, means including a second diode operating as a filter capacitor connected between said second input point and the gate electrode of said last-named IGFET, and an inverter circuit connected between the input terminal of said first diode and the gate
References Cited (Backward Citations)
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US3246173A
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US3424870A
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US3441685A
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US3428832A
Cited
US3509375A
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US3521141A
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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) | 1974-10-11 | 1975-04-12 | 1975-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-11 | 1979-04-12 | 1979-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-11 | 1983-04-12 | 1983-10-12 | $7700.00 | Window Closed / Lapsed |