In broadcasting, a transposer is a device in or beyond the service area of a radio or television station transmitter that rebroadcasts signals to receivers which can’t properly receive the signals of the transmitter because of a physical obstruction (like a hill). A transposer receives the signals of the transmitter and rebroadcasts the signals to the area of poor reception.

Guitar transposer pedal
The Use of the Transposer for the Management of the Deaf Child
A low-power matrix transposer using MSB-controlled inversion coding
Modelling and identification of the CFT-transposer robot
Genotype transposer: automated genotype manipulation for linkage disequilibrium analysis.
Some suggestions on how to evaluate a transposer hearing aid
Passive Microwave Transposer, Frequency Doubler for Detecting the Avalanche Victims
Selective Phoneme Spotting for Realization of an /s, z, C, t/ Transposer
Speech Discrimination by Sensorineural Hearing-Impaired Persons Using a Transposer Hearing Aid
Environnement urbain et obésité : peut-on transposer en Europe les approches nord-américaines ?