|
US2516271A
|
|
Supporting frame for food grinders and the like
|
|
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|
|
Oscilloscope sweep circuit
|
|
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|
|
Electrical delay device
|
|
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|
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Wavemeter
|
|
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|
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Keying radio transmitter
|
|
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|
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Crystal oscillator
|
|
US1998469A
|
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Crystal oscillator circuit for tetrodes
|
|
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|
|
System for detecting objects by radio
|
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US1979297A
|
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Aircraft altitude determination system
|
|
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|
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Receiving system for high-frequency electrical oscillations
|
|
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|
|
Apparatus for recording electrical signals
|
|
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|
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Receiver of high-frequency electrical signals
|
|
US658051A
|
|
Ribbon-holder.
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