Definition of "duplexer"

At first, making a duplexer seemed impossible, of all the filters in the cell phone, the specifications for the duplexer were by far the most stringent.

2009, Ken-ya Hashimoto, RF Bulk Acoustic Wave Filters for Communications‎, page 119

The HE11 mode emits a Gaussian beam into free space as is required for input to the quasi-optical duplexer attached to the antenna.

2011, Alastair D. McAulay, Military Laser Technology for Defense‎, page 272

A drawback in the dual duplexer design is that six channels are lost because three band gaps are required.

2012, TV White Space Spectrum Technologies‎