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US2360719A
|
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Telegraph system
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US2332469A
|
|
Television and telephotographic system
|
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GB498435A
|
|
Electrostatic microphone system
|
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GB508103A
|
|
Improvements in or relating to means for the transmission of telegrams over telephone wires
|
|
US2009520A
|
|
Electroacoustic device
|
|
GB307794A
|
|
Improvements in or relating to processes for the manufacture of membranes for electrostatic loud speakers
|
|
US1748901A
|
|
Membrane for electrostatic loud-speakers
|
|
US1747952A
|
|
Electrostatic loud-speaker
|
|
GB318876A
|
|
Improvements in or relating to electrostatic loud speakers and the like
|
|
GB300252A
|
|
Improvements in or relating to circuit arrangements suitable for biassing electrostatic loud speakers
|
|
US1859170A
|
|
Electrostatic telephone and microphone
|
|
GB258542A
|
|
Improvements in or relating to diaphragmless microphones
|
|
GB258476A
|
|
Improvements relating to non-resonant diaphragms for telephonic, microphonic and like apparatus
|
|
US1634210A
|
|
Diaphragmless microphone
|
|
GB250430A
|
|
Improvements in or relating to microphones
|
|
US1445412A
|
|
Process for producing sound waves
|
|
US1500037A
|
|
Method and apparatus for producing moving pictures and sound waves at the same time
|
|
US1523898A
|
|
Electrical circuit for thermionic discharge devices
|
|
GB169425A
|
|
A process for simultaneously recording and simultaneously reproducing optical images and sound waves
|
|
GB169424A
|
|
An improved process for producing combined records of optical images and sound vibrations
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