Patent US2988661A successfully refreshed from Google Patents.
Patent US5219354A successfully refreshed from Google Patents.
US4037065A
Expired / Lapsed
US
⏱️ 0.0 years remaining
20 Hz Ringdown solid state two-wire/four-wire converter
Assignee: United States Department of the Navy
•
Filing: 1976-10-04
•
Granted: 1977-07-19
•
Expires: 1996-10-04
Abstract
Abstract A hybrid system utilizing a plurality of operational amplifiers provides for appropriate isolation of input and output signalling. A signal initially appearing at the incoming path of the four-wire line appears as a balanced signal at the two-wire input/output end of the system but is effectively canceled from appearing at the ouput path of the four-wire input/output end. A signal initially placed on the two-wire input/output end of the system appears at the output of the four-wire input/output end but is effectively canceled from the input line of the four-wire input/output end. A 20 Hz threshold detector senses signals from the two-wire input/output line.
Inventors
- 👤 Lawrence P. Nahay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:23
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54; H04B1/58; H04B1/586
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
189 words
A 20 Hz ringdown solid state two-wire/four-wire converter system comprising: four-wire input terminals, four-wire output terminals and a pair of two-wire input/output terminals; an inverting solid state constant current driver and a non-inverting solid state constant current driver, said drivers in combination connected to transmit and balance a signal from said four-wire input terminals to said two-wire input/output terminals; balancing means for use in inhibiting signals from said four-wire input terminals from appearing at said four-wire output terminals, said balancing means connected to said four-wire input terminals; amplifier means connected at its input to said inverting constant current driver, said non-inverting constant current driver, said balancing means and said pair of two-wire input/output terminals for transmitting signals originating in the converter system at said two-wire input/output terminals and for inhibiting signals originating in the converter system at said four-wire input terminals; threshold detector means connected to the output of said amplifier means for conducting 20 Hz ringdown signals and rejecting other signals transmitted by said amplifier means; and said four-wire output terminals connected to said output of said amplifier means for receiving said other signals from said amplifier means.
Claim 2
Dependent Claim
189 words
A 20 Hz ringdown solid state two-wire/four-wire converter system comprising: four-wire input terminals, four-wire output terminals and a pair of two-wire input/output terminals; an inverting solid state constant current driver and a non-inverting solid state constant current driver, said drivers in combination connected to transmit and balance a signal from said four-wire input terminals to said two-wire input/output terminals; balancing means for use in inhibiting signals from said four-wire input terminals from appearing at said four-wire output terminals, said balancing means connected to said four-wire input terminals; amplifier means connected at its input to said inverting constant current driver, said non-inverting constant current driver, said balancing means and said pair of two-wire input/output terminals for transmitting signals originating in the converter system at said two-wire input/output terminals and for inhibiting signals originating in the converter system at said four-wire input terminals; threshold detector means connected to the output of said amplifier means for conducting 20 Hz ringdown signals and rejecting other signals transmitted by said amplifier means; and said four-wire output terminals connected to said output of said amplifier means for receiving said other signals from said amplifier means.
Claim 3
Dependent Claim
45 words
A 20 Hz ringdown solid state two-wire/four-wire converter system according to claim 1 wherein said balancing means further comprises: a constant current amplifier having an input connected to said four-wire input terminals; and a balancing network connected to the output of said constant current amplifier.
Claim 4
Dependent Claim
38 words
A 20 Hz ringdown solid state two-wire/four-wire converter system according to claim 2 wherein each of said inverting solid state constant current driver, non-inverting solid state current driver, constant current amplifier and amplifier means comprises an operational amplifier.
Claim 5
Dependent Claim
135 words
A 20 Hz ringdown solid state two-wire/four-wire converter system according to claim 3 wherein said threshold detector means further comprises a pair of oppositely biased diodes respectively connected to the output of said amplifier means; a pair of oppositely biased zener diodes respectively connected to said diodes; an operational amplifier having a pair of input terminals respectively connected to said zener diodes; adaptive means adapted for connecting a D.C. bias to one of said operational amplifier input terminals; connecting means having a pair of resistors for grounding each of said operational input terminals through one of said pair of resistors; and output means having an output terminal connected to the output of said operational amplifier, said output means further having a zener diode and a capacitor each respectively connecting said operational amplifier output with ground.
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) | 1980-07-18 | 1981-01-17 | 1981-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-18 | 1985-01-17 | 1985-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-18 | 1989-01-17 | 1989-07-19 | $7700.00 | Window Closed / Lapsed |