Patent US3781912A successfully refreshed from Google Patents.
US3781912A
Expired / Lapsed
US
⏱️ 0.0 years remaining
N-way analog signal fader
Assignee: Collins Radio Co
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Filing: 1972-12-29
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Granted: 1973-12-25
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Expires: 1992-12-29
Abstract
Abstract A DC analog signal fader employing a single operational amplifier permits fading onto a common output the level of a selected one of a plurality of input signals. A newly selected signal is faded from the level of a next previously selected input and in a manner which does not introduce lag or step level changes at the output.
Inventors
- 👤 J Mccollum
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:58
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
225 words
An analog signal fader for fading any one of a plurality of DC input signals onto a common output line from the level of a next previously selected one of said plurality of input signals comprising; an operational amplifier having a noninverting input, an inverting input, and an output terminal comprising said common output line, a feedback resistor connected between said amplifier output terminal and said inverting input; a plurality of switching means; each of said plurality of input signals being selectively applied through an energized position of an associated one of said switching means to said noninverting input of said operational amplifier; a plurality of capacitors, each of said plurality of input signals being selectively applied through a de-energized position of said associated one of said switching means and through said associated one of said capacitors to said operational amplifier output terminal; each of said capacitors, through an energized position of said associated one of said switching means being connected in parallel with said operational amplifier feedback resistor; and means for selectively energizing a selected one of said switching means to the exclusion of the remaining ones of such switching means in response to which the output of said operational amplifier is faded from an existing level to that defined by the input signal applied to said selectively energized one of said switching means.
Claim 2
Dependent Claim
225 words
An analog signal fader for fading any one of a plurality of DC input signals onto a common output line from the level of a next previously selected one of said plurality of input signals comprising; an operational amplifier having a noninverting input, an inverting input, and an output terminal comprising said common output line, a feedback resistor connected between said amplifier output terminal and said inverting input; a plurality of switching means; each of said plurality of input signals being selectively applied through an energized position of an associated one of said switching means to said noninverting input of said operational amplifier; a plurality of capacitors, each of said plurality of input signals being selectively applied through a de-energized position of said associated one of said switching means and through said associated one of said capacitors to said operational amplifier output terminal; each of said capacitors, through an energized position of said associated one of said switching means being connected in parallel with said operational amplifier feedback resistor; and means for selectively energizing a selected one of said switching means to the exclusion of the remaining ones of such switching means in response to which the output of said operational amplifier is faded from an existing level to that defined by the input signal applied to said selectively energized one of said switching means.
Claim 3
Dependent Claim
57 words
An analog signal fader as defined in claim 1 comprising a further resistor member like that of said operational amplifier feedback resistor connected to said operational amplifier noninverting input, and through which said selected one of said plurality of input signals is applied through energized ones of said associated switching means to said operational amplifier noninverting input.
Claim 4
Dependent Claim
57 words
An analog signal fader as defined in claim 2 comprising a further plurality of resistive members, each of said plurality of input signals being applied through an associated one of said further plurality of resistive members to said associated ones of said capacitors with the associated one of said plurality of switching means in a de-energized position.
Claim 5
Dependent Claim
67 words
An analog signal fader as defined in claim 3 wherein said switching means comprises logic means for energizing the switch associated with a selected input signal to the exclusion of the remaining ones of said switches, said selected switch energization being maintained until a next successively selected one of said switches is energized to fade the associated one of said input signals to said common output line.
References Cited (Backward Citations)
US2937369A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |