US3866148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplitude modulator having a transistor controlled bias current
Assignee: United States Department of the Navy
•
Filing: 1973-11-23
•
Granted: 1975-02-11
•
Expires: 1993-11-23
Abstract
Abstract An amplitude modulator capable of 100% modulation with low modulation distortion, adaptable to all practical amplitude modulation requirements from D.C. to 120 MHz. The circuit has a differential amplifier with an R.F. input and a bias current from an ultra-linear, voltage-tuned constant current source which is transistor controlled. The differential amplifier provides full limiting of the R.F. input and is biased with a current source comprised of an operational amplifier with its feedback connected to include the bias current controlling transistor.
Inventors
- 👤 Jr Thomas K Lisle
- 👤 Joseph Romanchak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:34
CPC Classifications
H; H03; H03C; H03C1/00; H03C1/52; H03C1/54; H03C1/542; H03C1/545; H03C2200/00; H03C2200/0004; H03C2200/0012; H03C2200/0037; H03C2200/0079
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
95 words
An amplitude modulator having low modulation distortion comprising: a. a common-emitter differential amplifier; b. means for applying a carrier signal to said amplifier; c. means for applying a reference voltage to said amplifier; d. a transistor having its collector junction connected to the common emitter connection of said amplifier for biasing said amplifier with a voltage-controlled, linear-tuning, constant current modulation signal; e. an operational amplifier connected to the base of said transistor, the feedback path of said operational amplifier being coupled to the emitter of said transistor whereby the non-linearity of said transistor is eliminated.
Claim 2
Dependent Claim
95 words
An amplitude modulator having low modulation distortion comprising: a. a common-emitter differential amplifier; b. means for applying a carrier signal to said amplifier; c. means for applying a reference voltage to said amplifier; d. a transistor having its collector junction connected to the common emitter connection of said amplifier for biasing said amplifier with a voltage-controlled, linear-tuning, constant current modulation signal; e. an operational amplifier connected to the base of said transistor, the feedback path of said operational amplifier being coupled to the emitter of said transistor whereby the non-linearity of said transistor is eliminated.
Claim 3
Dependent Claim
36 words
The amplitude modulator of claim 1 wherein the means for applying a reference voltage to said differential amplifier includes means conneCted between the bases of the differential amplifier for blocking carrier excursions from the reference side.
Claim 4
Dependent Claim
19 words
The amplitude modulator of claim 2 wherein the means for blocking excursions of the carrier signal is an inductor.
Claim 5
Dependent Claim
25 words
The amplitude modulator of claim 3 wherein filter means for reclaiming the fundamental carrier frequency is connected to one collector electrode of said differential amplifier.
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) | 1978-02-10 | 1978-08-12 | 1979-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-10 | 1982-08-12 | 1983-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-10 | 1986-08-12 | 1987-02-11 | $7700.00 | Window Closed / Lapsed |