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US2559227A
|
|
Shock wave generator
|
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GB633429A
|
|
Frequency determining unit
|
|
US2570485A
|
|
Electrical sorting system
|
|
US2521401A
|
|
Variable frequency vibrator
|
|
US2542944A
|
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Dew point meter
|
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GB622097A
|
|
Improvements in devices for determining the direction of origin of a sound
|
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US2447818A
|
|
Periodic reversing drive
|
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US2466327A
|
|
Damping device
|
|
US2477085A
|
|
Frequency controlled micrometer
|
|
US2424634A
|
|
Theater amplifying and sound distribution system
|
|
US2397579A
|
|
Sound reproducing system
|
|
US2424633A
|
|
Acoustic reservoir for use in a magnetic sound recording and reproducing system
|
|
US2429427A
|
|
Frequency controlled frequency meter
|
|
US2469786A
|
|
Electric motor control device
|
|
US2424773A
|
|
Locating device
|
|
US2513678A
|
|
Frequency controlled weighing device
|
|
US2412536A
|
|
Mechanically tuned oscillator
|
|
US2447817A
|
|
Temperature or pressure responsive variable frequency oscillator
|
|
US2447816A
|
|
Temperature responsive variable frequency oscillator
|
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US2455021A
|
|
Pressure meter
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