US3728645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High modulation index oscillator-modulator circuit
Assignee: Microcom Corp
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Filing: 1971-05-20
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Granted: 1973-04-17
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Expires: 1991-05-20
Abstract
Abstract An oscillator-modulator circuit is disclosed wherein a high modulation index is obtained by shunting across the crystal of an oscillator a first capacitance derived across the output terminals of a modulation amplifier transistor and a second capacitance derived across the input terminals of the oscillator transistor, such first and second capacitances being time varied by the modulation signal. Oscillator startup under low temperature conditions is aided by circuit delay in coupling the effective capacitance of the modulator amplifier transistor in shunt with the crystal, thereby providing higher closed loop gain of the oscillator during the initial start-up time period.
Inventors
- 👤 C Rosen
- 👤 M Arcaro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:37
CPC Classifications
H; H03; H03C; H03C3/00; H03C3/10; H03C3/12; H03C3/14; H03C3/145
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
283 words
Modulator-oscillator apparatus, for producing a high frequency electrical signal which is amplitude and phase modulated by a modulation signal, comprising: a. a transistor amplifier having a first transistor with an effective output capacitor between its collector and emitter the value of which varies as a function of the voltage on the collector of said transistor, said amplifier having an input terminal connected to the base of saId first transistor and to which said modulation signal is connected, and an output terminal connected to the collector of said first transistor and at which said modulation signal appears in amplified form, said amplified signal thus varying the value of said effective output capacitor; b. a crystal controlled oscillator, having a second transistor and a crystal connected to the base of said second transistor; c. a fixed value capacitor connected in shunt with said crystal; d. said second transistor having an effective input capacitor between its base and emitter which is a function of the voltage on said base of said second transistor, said effective input capacitor being connected in shunt with said crystal; e. coupling means for coupling said first transistor collector to the base of said second transistor and to said crystal, thereby connecting said effective output capacitor and said effective input capacitor together in shunt with said crystal and causing the amplified modulation signal to vary the effective value of said input capacitor; and f. said fixed capacitor, output capacitor and input capacitor being of a combined value so as to fix the operating point of said oscillator for said linear modulation, the amplitude and phase of said oscillation signal being varied when said modulation signal is connected to said amplifier input terminal.
Claim 2
Dependent Claim
283 words
Modulator-oscillator apparatus, for producing a high frequency electrical signal which is amplitude and phase modulated by a modulation signal, comprising: a. a transistor amplifier having a first transistor with an effective output capacitor between its collector and emitter the value of which varies as a function of the voltage on the collector of said transistor, said amplifier having an input terminal connected to the base of saId first transistor and to which said modulation signal is connected, and an output terminal connected to the collector of said first transistor and at which said modulation signal appears in amplified form, said amplified signal thus varying the value of said effective output capacitor; b. a crystal controlled oscillator, having a second transistor and a crystal connected to the base of said second transistor; c. a fixed value capacitor connected in shunt with said crystal; d. said second transistor having an effective input capacitor between its base and emitter which is a function of the voltage on said base of said second transistor, said effective input capacitor being connected in shunt with said crystal; e. coupling means for coupling said first transistor collector to the base of said second transistor and to said crystal, thereby connecting said effective output capacitor and said effective input capacitor together in shunt with said crystal and causing the amplified modulation signal to vary the effective value of said input capacitor; and f. said fixed capacitor, output capacitor and input capacitor being of a combined value so as to fix the operating point of said oscillator for said linear modulation, the amplitude and phase of said oscillation signal being varied when said modulation signal is connected to said amplifier input terminal.
Claim 3
Dependent Claim
165 words
A modulator-oscillator, for generating a high frequency signal modulated by a relatively low frequency modulation signal, comprising: a. an oscillator for generating said high frequency signal having a crystal in shunt with a fixed capacitor and a first voltage controlled capacitor; b. a second voltage controlled capacitor connected to said modulation signal such that its effective value is varied thereby; c. a power supply connected to said oscillator and said second voltage controlled capacitor; and d. a delay circuit coupling said second voltage controlled capacitor in shunt with said crystal such that when said power supply is coupled to said oscillator and said second voltage controlled capacitor, said second voltage controlled capacitor is not effectively coupled to said oscillator until after a predetermined time delay, during which time said oscillator appreciably reaches a steady state output, and after which time the amplitude and phase of said high frequency signal is varied as a function of the changing effective value of said second voltage controlled capacitor.
Claim 4
Dependent Claim
165 words
A modulator-oscillator, for generating a high frequency signal modulated by a relatively low frequency modulation signal, comprising: a. an oscillator for generating said high frequency signal having a crystal in shunt with a fixed capacitor and a first voltage controlled capacitor; b. a second voltage controlled capacitor connected to said modulation signal such that its effective value is varied thereby; c. a power supply connected to said oscillator and said second voltage controlled capacitor; and d. a delay circuit coupling said second voltage controlled capacitor in shunt with said crystal such that when said power supply is coupled to said oscillator and said second voltage controlled capacitor, said second voltage controlled capacitor is not effectively coupled to said oscillator until after a predetermined time delay, during which time said oscillator appreciably reaches a steady state output, and after which time the amplitude and phase of said high frequency signal is varied as a function of the changing effective value of said second voltage controlled capacitor.
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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) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |