Patent US4361817A successfully refreshed from Google Patents.
US4361817A
Expired / Lapsed
US
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Bi-phase modulator/demodulator
Assignee: Honeywell Inc
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Filing: 1980-10-27
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Granted: 1982-11-30
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Expires: 2000-10-27
Abstract
Abstract A bi-phase modulator/demodulator circuit for converting uni-polar to bi-polar signals. The circuit can be used to bi-phase modulate a continuous wave (CW) input signal or to demodulate a bi-phase coded input signal by use of transistor-transistor logic (TTL) control signals. A tri-state logic gate is used to convert two digital signals to an unbiased AC signal which is applied to one of two inputs of a double balanced mixer. The other input of the mixer is adapted to receive a continuous wave signal for bi-phase modulation, or a bi-phase coded signal for demodulation.
Inventors
- 👤 HarryF. Stillwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:58
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4904
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
253 words
A bi-phase modulator-demodulator circuit for converting uni-polar to bi-polar signals, comprising: a tri-state logic gate having first and second inputs for receiving first and second digital signals and having an output; a first amplifier stage including a first transistor having a base electrode connected to receive the signal from the output of said tri-state logic gate and having an emitter electrode and a collector electrode; impedance means for interconnecting said electrodes of said first transistor between sources of first and second potential so as to allow the signal at the collector electrode to swing linearly by a predetermined voltage amount in either direction from a reference potential; means for providing DC isolation between the output of said tri-state logic gate and the base electrode of said first transistor a second amplifier stage including second and third complementary transistors connected to receive an input signal at a common junction joining their respective base electrodes, and to provide an output at a common junction joining their respective emitter electrodes, and further having their collectors respectively connected to sources of positive and negative potential; means for providing DC isolation between the output of said first amplifier stage and the input of said second amplifier stage; means for limiting the voltage swing at the output of said second amplifier stage between predetermined positive and negative voltage levels; and a double balanced mixer having a first input connected to receive the signal from the output of said second amplifier stage and having a second input and an output.
Claim 2
Dependent Claim
253 words
A bi-phase modulator-demodulator circuit for converting uni-polar to bi-polar signals, comprising: a tri-state logic gate having first and second inputs for receiving first and second digital signals and having an output; a first amplifier stage including a first transistor having a base electrode connected to receive the signal from the output of said tri-state logic gate and having an emitter electrode and a collector electrode; impedance means for interconnecting said electrodes of said first transistor between sources of first and second potential so as to allow the signal at the collector electrode to swing linearly by a predetermined voltage amount in either direction from a reference potential; means for providing DC isolation between the output of said tri-state logic gate and the base electrode of said first transistor a second amplifier stage including second and third complementary transistors connected to receive an input signal at a common junction joining their respective base electrodes, and to provide an output at a common junction joining their respective emitter electrodes, and further having their collectors respectively connected to sources of positive and negative potential; means for providing DC isolation between the output of said first amplifier stage and the input of said second amplifier stage; means for limiting the voltage swing at the output of said second amplifier stage between predetermined positive and negative voltage levels; and a double balanced mixer having a first input connected to receive the signal from the output of said second amplifier stage and having a second input and an output.
Claim 3
Dependent Claim
88 words
Apparatus according to claim 1, wherein said means for limiting the voltage swing at the output of said second amplifier stage includes: a first diode connected between the common base junction of said second and third transistors and via a first voltage divider to said source of positive potential; and a second diode connected between the common base junction of said second and third transistors and via a second voltage divider to said source of negative potential; whereby said first and second diodes further provide desirable temperature compensation.
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) | 1985-11-29 | 1986-05-31 | 1986-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-29 | 1990-05-31 | 1990-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-29 | 1994-05-31 | 1994-11-30 | $7700.00 | Window Closed / Lapsed |