voice amplifier造句

• By 1928, DuMont was searching for new opportunities and was wooed by Dr . Lee De Forest, a radio pioneer who developed the audion tube, the original voice amplifier for radio reception.
• As ALS progresses, speech-language pathologists can recommend the use of augmentative and alternative communication such as voice amplifiers, speech-generating devices ( or voice output communication devices ) and / or low tech communication techniques such as head mounted laser pointers, alphabet boards or yes / no signals.