Patent US3718987A successfully refreshed from Google Patents.
US3718987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aircraft sound simulation system
Assignee: CAE Link Corp
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Filing: 1970-09-10
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Granted: 1973-03-06
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Expires: 1990-09-10
Abstract
Abstract Sound generation apparatus to simulate the sounds made by a jet engine. By adding the outputs of two nominally identical oscillators constructed using non-precision components which cause them to have slightly different output frequencies a sound closely simulating whine is obtained. Amplitude of sound is controlled by the use of field effect transistor shunts which have applied to their gates signals representing the parameters which affect the level of sound heard by a listener.
Inventors
- 👤 F Carver
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:56
CPC Classifications
H; H03; H03B; H03B29/00; G; G10; G10H; G10H5/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
149 words
Apparatus to simulate the whine of a jet engine comprising: a. a pair of nominally identical voltage controlled sawtooth oscillators constructed using non-precision components, said oscillators having a common voltage control input and a common output, said common control input of said oscillators having as a first input a voltage proportional to the RPM of the engine being simulated; b. means to provide as a second input to said common control input a voltage dependent on the engine being fired, said voltage being of a first polarity when said engine is not fired and of a second polarity when said engine is fired; c. an amplifier having an input connected to the output of said pair of oscillators; and d. a speaker connected to the output of said amplifier whereby a basic frequency and harmonics sounding like the whine of a jet engine will be produced, amplified, and broadcast.
Claim 2
Dependent Claim
149 words
Apparatus to simulate the whine of a jet engine comprising: a. a pair of nominally identical voltage controlled sawtooth oscillators constructed using non-precision components, said oscillators having a common voltage control input and a common output, said common control input of said oscillators having as a first input a voltage proportional to the RPM of the engine being simulated; b. means to provide as a second input to said common control input a voltage dependent on the engine being fired, said voltage being of a first polarity when said engine is not fired and of a second polarity when said engine is fired; c. an amplifier having an input connected to the output of said pair of oscillators; and d. a speaker connected to the output of said amplifier whereby a basic frequency and harmonics sounding like the whine of a jet engine will be produced, amplified, and broadcast.
Claim 3
Dependent Claim
149 words
Apparatus to simulate the whine of a jet engine comprising: a. a pair of nominally identical voltage controlled sawtooth oscillators constructed using non-precision components, said oscillators having a common voltage control input and a common output, said common control input of said oscillators having as a first input a voltage proportional to the RPM of the engine being simulated; b. means to provide as a second input to said common control input a voltage dependent on the engine being fired, said voltage being of a first polarity when said engine is not fired and of a second polarity when said engine is fired; c. an amplifier having an input connected to the output of said pair of oscillators; and d. a speaker connected to the output of said amplifier whereby a basic frequency and harmonics sounding like the whine of a jet engine will be produced, amplified, and broadcast.
Claim 4
Dependent Claim
149 words
Apparatus to simulate the whine of a jet engine comprising: a. a pair of nominally identical voltage controlled sawtooth oscillators constructed using non-precision components, said oscillators having a common voltage control input and a common output, said common control input of said oscillators having as a first input a voltage proportional to the RPM of the engine being simulated; b. means to provide as a second input to said common control input a voltage dependent on the engine being fired, said voltage being of a first polarity when said engine is not fired and of a second polarity when said engine is fired; c. an amplifier having an input connected to the output of said pair of oscillators; and d. a speaker connected to the output of said amplifier whereby a basic frequency and harmonics sounding like the whine of a jet engine will be produced, amplified, and broadcast.
Claim 5
Dependent Claim
14 words
Apparatus according to claim 1 further including a roar generator connected to said amplifier.
Claim 6
Dependent Claim
72 words
Apparatus according to claim 2 wherein said roar generator comprises: a. a white noise generator; b. filter means connected to said white noise generator to cause the output of said roar generator to contain only frequencies found in the roar noise of a jet engine; c. voltage attenuator means having as attenuating inputs a voltage of first polarity proportional to engine RPM and a voltage of opposite polarity proportional to mach number.
Claim 7
Dependent Claim
64 words
Apparatus according to claim 3 wherein said attenuator means comprises a field effect transistor having its source connected to said roar generator output, its drain to ground and having on its gate the summation of voltages representing RPM and mach number and wherein the RPM voltage will tend to keep said transistor off and the mach number will tend to turn said transistor on.
Claim 8
Dependent Claim
26 words
Apparatus according to claim 2 and further including voltage controlled attenuation means having said amplifier output as an input and providing its output to said speakers.
Claim 9
Dependent Claim
60 words
Apparatus according to claim 5 wherein said attenuator means comprise field effect transistors having their sources connected to said amplifier output, their drains connected to ground and their gates to signals representing parameters effecting the sound heard by a listener whereby when the audible sound decreases said signals will cause increasing portions of the sound to be shunted to ground.
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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) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |