US4485359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplitude modulator having substantially zero modulation distortion
Assignee: Individual
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Filing: 1983-03-28
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Granted: 1984-11-27
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Expires: 2003-03-28
Abstract
Abstract An improved substantially "zero distortion" four quadrant modulator of the type including a pair of differential elements respectively coupled to the Y input port terminals of the modulator and exhibiting nonlinear amplitude transfer functions, includes the means for substantially linearizing the nonlinear transfer function. The means includes a pair of operational amplifiers, each having an input coupled to a respective terminal of the Y input port and an output coupled to the corresponding differential element so that the differential element is disposed in the feedback path of the operational amplifier.
Inventors
- 👤 Daniel B. Talbot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 12:20
CPC Classifications
H; H03; H03D; H03D1/00; H03D1/02; H03D1/06
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
212 words
An amplitude modulator comprising a first pair of terminals for receiving an input signal, a second pair of input terminals for receiving a carrier signal, signal multiplication means coupled to said first and second pairs of input terminals for multiplying said input signal with said carrier signal, and a pair of output terminals for providing a signal as a function of the multiplication product of the input signal and the carrier signal, said multiplication means comprising a pair of differential elements for measuring the difference in potential between the terminals of said first pair, each of said differential elements including an input and an output and exhibiting a nonlinear amplitude transfer function between the input and output, the inputs of said elements being respectively coupled to the input terminals of said first pair, wherein the improvement comprises: means including a pair of operational amplifiers, each of said amplifiers including an inverting input, a non-inverting input and an output, said non-inverting input being coupled to a corresponding input terminal of the first pair and said output being coupled to the corresponding differential element and to said inverting input so that the amplitude transfer function between said non-inverting input of said operational amplifier and the output of the corresponding differential element is substantially linear.
Claim 2
Dependent Claim
212 words
An amplitude modulator comprising a first pair of terminals for receiving an input signal, a second pair of input terminals for receiving a carrier signal, signal multiplication means coupled to said first and second pairs of input terminals for multiplying said input signal with said carrier signal, and a pair of output terminals for providing a signal as a function of the multiplication product of the input signal and the carrier signal, said multiplication means comprising a pair of differential elements for measuring the difference in potential between the terminals of said first pair, each of said differential elements including an input and an output and exhibiting a nonlinear amplitude transfer function between the input and output, the inputs of said elements being respectively coupled to the input terminals of said first pair, wherein the improvement comprises: means including a pair of operational amplifiers, each of said amplifiers including an inverting input, a non-inverting input and an output, said non-inverting input being coupled to a corresponding input terminal of the first pair and said output being coupled to the corresponding differential element and to said inverting input so that the amplitude transfer function between said non-inverting input of said operational amplifier and the output of the corresponding differential element is substantially linear.
Claim 3
Dependent Claim
47 words
A modulator according to claim 1, wherein each of said differential elements includes the base emitter junction of a transistor, said base emitter junction being disposed in a feedback path of the corresponding operational amplifier between said output and said inverting input of said corresponding operational amplifier.
Claim 4
Dependent Claim
16 words
A modulator according to claim 2, further including means for setting the gain of said modulator.
Claim 5
Dependent Claim
27 words
A modulator according to claim 3, wherein said means for setting said gain includes a resistor coupled between emitters of said corresponding transistors of said differential elements.
Claim 6
Dependent Claim
19 words
A modulator according to claim 2, further including means for stabilizing said feedback path of each said operational amplifier.
Claim 7
Dependent Claim
29 words
A modulator according to claim 5, further including a resistor coupled between the output of said operational amplifier and the base of the corresponding transistor of said differential elements.
Claim 8
Dependent Claim
53 words
A modulator according to claim 6, wherein said means for stabilizing said feedback path includes a second resistor coupled between the emitter of the corresponding transistor of said differential elements and said inverting input of said corresponding operational amplifier, and a capacitor coupled between the output and inverting input of each operational amplifier.
Claim 9
Dependent Claim
137 words
An amplitude modulator comprising: a common-emitter diffential amplifier; means for applying a carrier signal to said differential amplifier; and means for applying a modulation signal to said common emitters of said differential amplifier so that an amplitude modulated signal is provided at the output of said differential amplifier, said means for applying said modulation signal comprising an operational amplifier having one input coupled to receive a modulation input signal and the other input coupled to its output so as to form a feedback path for said operational amplifier, a transistor having its base-emitter junction connected in said feedback path and its collector coupled to said common-emitters for applying said modulation signal to said common emitters; wherein the amplitude transfer function between said one input of said operational amplifier and said collector of said transistor is substantially linear.
Claim 10
Dependent Claim
137 words
An amplitude modulator comprising: a common-emitter diffential amplifier; means for applying a carrier signal to said differential amplifier; and means for applying a modulation signal to said common emitters of said differential amplifier so that an amplitude modulated signal is provided at the output of said differential amplifier, said means for applying said modulation signal comprising an operational amplifier having one input coupled to receive a modulation input signal and the other input coupled to its output so as to form a feedback path for said operational amplifier, a transistor having its base-emitter junction connected in said feedback path and its collector coupled to said common-emitters for applying said modulation signal to said common emitters; wherein the amplitude transfer function between said one input of said operational amplifier and said collector of said transistor is substantially linear.
Claim 11
Dependent Claim
30 words
A modulator according to claim 8, wherein said one input of said operational amplifier is the non-inverting input and said other input of said operational amplifier is the inverting input.
Claim 12
Dependent Claim
18 words
A modulator according to claim 9, further including means for stabilizing said feedback path of said operational amplifier.
Claim 13
Dependent Claim
24 words
A modulator according to claim 10, further including a resistor coupled between the output of said operational amplifier and the base of said transistor.
Claim 14
Dependent Claim
47 words
A modulator according to claim 11, wherein said means for stabilizing said feedback path includes a second resistor coupled between the emitter of said transistor and said inverting input of said operational amplifier, and a capacitor coupled between the output and inverting input of said operational amplifier.
References Cited (Backward Citations)
US3866148A
Cited
US3974460A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-27 | 1988-05-28 | 1988-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-27 | 1992-05-28 | 1992-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-27 | 1996-05-28 | 1996-11-27 | $7700.00 | Window Closed / Lapsed |