US4035738A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low noise amplifier
Assignee: United States Department of the Navy
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Filing: 1976-05-17
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Granted: 1977-07-12
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Expires: 1996-05-17
Abstract
Abstract A low-noise, stage-stabilized, direct-coupled, single-ended amplifier cirt is disclosed which has a unique feedback network combined therewith in such manner that degenerative alternating current and substantially constant direct current feedback signals are supplied thereto, so as to effect an exceptionally steady amplification factor therefor over a very broad frequency response band.
Inventors
- 👤 Philip J. Anzalone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:49
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/34; H03F1/342; H03F3/00; H03F3/189; H03F3/19; H03F3/193; H03F3/1935; H03F2200/00; H03F2200/372
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
640 words
An amplifier, comprising in combination: a transformer having a primary winding and a secondary winding; a field effect transistor having a gate, a source, and a drain, with the gate thereof connected to one of the terminals of the secondary winding of said transformer; a first battery having a positive terminal and a negative terminal; a first resistance connected between the drain of said field effect transistor and the positive terminal of said first battery; a first transistor having a base, an emitter, and a collector, with the emitter connected to the drain of said field effect transistor; a second resistance connected between the base of said first transistor and the positive terminal of the aforesaid first battery; a first capacitance connected in parallel with said second resistance; a third resistance connected between the collector of said first transistor and the positive terminal of said first battery; a second transistor having a base, an emitter, and a collector, with the base thereof connected to the collector of said first transistor; a series connected fourth resistance and second capacitance connected between the base of said second transistor and the positive terminal of said first battery; a fifth resistance connected between the base of said first transistor and the negative terminal of said first battery; a sixth resistance connected between the emitter of said second transistor and the positive terminal of said first battery; a series connected seventh resistance and third capacitance connected between the collector of said second transistor and the negative terminal of said first battery; operational amplifier means having a plurality of inputs and an output, with the data input thereof connected to the collector of said second transistor, with another of the inputs thereof directly connected to the positive terminal of said first battery; an eighth resistance connected between another of the inputs of said operational amplifier means and the positive terminal of said first battery; a fourth capacitance connected between the interconnection of said eighth resistance and the another of the inputs of said operational amplifier and the aforesaid negative terminal of said first battery; a fifth capacitance connected between the negative terminal of said first battery; a fifth capacitance connected between the negative terminal of said first battery and still another of the inputs of said operational amplifier; a second battery having a positive terminal and a negative terminal, with the positive terminal thereof connected to the negative terminal of said first battery, and with the negative terminal thereof connected to still another input of the aforesaid operational amplifier; a ninth resistance connected between the collector of said second transistor and the negative terminal of said second battery; a tenth resistance connected between the negative terminal of the aforesaid second batter and said still another of the inputs of said operational amplifier; an eleventh resistance, with one terminal thereof connected to the output of said operational amplifier; a twelth resistance connected between the other terminal of said eleventh resistance and the source of said field effect transistor; a thirteenth transistor, with one terminal thereof connected to the interconnection of said eleventh and twelth resistance; a fourteenth resistance, with one terminal thereof connected to the other terminal of said thirteenth resistance, and with the other terminal thereof connected to the negative terminal of said second battery; a fifteenth resistance, with one terminal thereof connected to the negative terminal of said second battery, and with the other terminal thereof connected to the other terminal of the secondary winding of the aforesaid transformer; a sixth capacitance connected between the other terminal of the secondary winding of said transformer and the negative terminal of said first battery; a sixteenth resistance connected in parallel with said sixth capacitance; and a seventh capacitance connected between the interconnection of said thirteenth and fourteenth resistances and the negative terminal of the aforesaid first battery.
Claim 2
Dependent Claim
640 words
An amplifier, comprising in combination: a transformer having a primary winding and a secondary winding; a field effect transistor having a gate, a source, and a drain, with the gate thereof connected to one of the terminals of the secondary winding of said transformer; a first battery having a positive terminal and a negative terminal; a first resistance connected between the drain of said field effect transistor and the positive terminal of said first battery; a first transistor having a base, an emitter, and a collector, with the emitter connected to the drain of said field effect transistor; a second resistance connected between the base of said first transistor and the positive terminal of the aforesaid first battery; a first capacitance connected in parallel with said second resistance; a third resistance connected between the collector of said first transistor and the positive terminal of said first battery; a second transistor having a base, an emitter, and a collector, with the base thereof connected to the collector of said first transistor; a series connected fourth resistance and second capacitance connected between the base of said second transistor and the positive terminal of said first battery; a fifth resistance connected between the base of said first transistor and the negative terminal of said first battery; a sixth resistance connected between the emitter of said second transistor and the positive terminal of said first battery; a series connected seventh resistance and third capacitance connected between the collector of said second transistor and the negative terminal of said first battery; operational amplifier means having a plurality of inputs and an output, with the data input thereof connected to the collector of said second transistor, with another of the inputs thereof directly connected to the positive terminal of said first battery; an eighth resistance connected between another of the inputs of said operational amplifier means and the positive terminal of said first battery; a fourth capacitance connected between the interconnection of said eighth resistance and the another of the inputs of said operational amplifier and the aforesaid negative terminal of said first battery; a fifth capacitance connected between the negative terminal of said first battery; a fifth capacitance connected between the negative terminal of said first battery and still another of the inputs of said operational amplifier; a second battery having a positive terminal and a negative terminal, with the positive terminal thereof connected to the negative terminal of said first battery, and with the negative terminal thereof connected to still another input of the aforesaid operational amplifier; a ninth resistance connected between the collector of said second transistor and the negative terminal of said second battery; a tenth resistance connected between the negative terminal of the aforesaid second batter and said still another of the inputs of said operational amplifier; an eleventh resistance, with one terminal thereof connected to the output of said operational amplifier; a twelth resistance connected between the other terminal of said eleventh resistance and the source of said field effect transistor; a thirteenth transistor, with one terminal thereof connected to the interconnection of said eleventh and twelth resistance; a fourteenth resistance, with one terminal thereof connected to the other terminal of said thirteenth resistance, and with the other terminal thereof connected to the negative terminal of said second battery; a fifteenth resistance, with one terminal thereof connected to the negative terminal of said second battery, and with the other terminal thereof connected to the other terminal of the secondary winding of the aforesaid transformer; a sixth capacitance connected between the other terminal of the secondary winding of said transformer and the negative terminal of said first battery; a sixteenth resistance connected in parallel with said sixth capacitance; and a seventh capacitance connected between the interconnection of said thirteenth and fourteenth resistances and the negative terminal of the aforesaid first battery.
Claim 3
Dependent Claim
27 words
The invention of claim 1, further characterized by a ground connected to the negative terminal of said first battery and the positive terminal of said second battery.
Claim 4
Dependent Claim
19 words
The invention of claim 1, further characterized by another capacitance connected to the output of the aforesaid operational amplifier.
Claim 5
Dependent Claim
289 words
A low noise, low frequency amplifier comprising in combination: a voltage step-up input transformer having a primary winding and a secondary winding; a field effect transistor having source, drain, and gate connections, said gate connection being connected only to a first end of said secondary, winding, said source connection being connected through resistance means to a negative voltage potential, and said drain connection being connected through resistance means to a positive voltage potential; a substantially linear direct current amplifier having an input connection and an output connection, said input connection being coupled to said drain connection of said field effect transistor so as to be responsive to changes in current flow therethrough to provide corresponding changes in voltage at said output connection; and a feedback network coupled to said output connection and operative to provide both direct current and alternating current negative feedback to said source connection of said field effect transistor; said feedback network comprising a first feedback resistor connected to said output connection, a second feedback resistor connected in series with said first feedback resistor, the junction between said first and second feedback resistors being coupled to said source connection, and a capacitor connected in series between said second feedback resistor and ground, whereby said second feedback resistor is effectively open circuited for direct current and substantially all of the direct current component of the output signal at said output connection is applied via said first feedback resistor to said source connection as direct current negative feedback, while for the alternating current component of said output signal said first and second feedback resistors comprise a voltage divider so a predetermined fraction of said alternating current component is applied to said source connection of said field effect transistor.
Claim 6
Dependent Claim
289 words
A low noise, low frequency amplifier comprising in combination: a voltage step-up input transformer having a primary winding and a secondary winding; a field effect transistor having source, drain, and gate connections, said gate connection being connected only to a first end of said secondary, winding, said source connection being connected through resistance means to a negative voltage potential, and said drain connection being connected through resistance means to a positive voltage potential; a substantially linear direct current amplifier having an input connection and an output connection, said input connection being coupled to said drain connection of said field effect transistor so as to be responsive to changes in current flow therethrough to provide corresponding changes in voltage at said output connection; and a feedback network coupled to said output connection and operative to provide both direct current and alternating current negative feedback to said source connection of said field effect transistor; said feedback network comprising a first feedback resistor connected to said output connection, a second feedback resistor connected in series with said first feedback resistor, the junction between said first and second feedback resistors being coupled to said source connection, and a capacitor connected in series between said second feedback resistor and ground, whereby said second feedback resistor is effectively open circuited for direct current and substantially all of the direct current component of the output signal at said output connection is applied via said first feedback resistor to said source connection as direct current negative feedback, while for the alternating current component of said output signal said first and second feedback resistors comprise a voltage divider so a predetermined fraction of said alternating current component is applied to said source connection of said field effect transistor.
Claim 7
Dependent Claim
33 words
An amplifier as defined in claim 4, and further characterized by transistor amplifier means for coupling said drain connection of said field effect transistor to said input connection of said direct current amplifier.
References Cited (Backward Citations)
US3239770A
Cited
US3487163A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |