|
GB518815A
|
|
Improvements in throat microphones and methods of adjusting the same
|
|
GB518814A
|
|
Improvements in telephone systems
|
|
GB518816A
|
|
Improvements in throat microphones
|
|
US2165123A
|
|
Contact microphone
|
|
US2121781A
|
|
Sound translating device
|
|
US2122191A
|
|
Sound translation apparatus
|
|
US2120882A
|
|
Modulator
|
|
US2121780A
|
|
Sound translating system
|
|
US2121779A
|
|
Sound translating apparatus
|
|
US2121778A
|
|
Sound translating apparatus
|
|
US1834443A
|
|
Cathode system for vacuum tubes
|
