If the right specifications are chosen, the duplexer has a narrow-enough filter to prevent the repeater's receiver from being overloaded by its own transmitter.
32.
An important subsequent development by Page was the duplexer, a device that allowed the transmitter and receiver to use the same antenna without overwhelming or destroying the sensitive receiver circuitry.
33.
Standard repeaters require either the use of two antennas ( one each for transmitter and receiver ) or a duplexer to isolate the transmit and receive signals over a single antenna.
34.
In addition to the duplexer, another major invention was the ring oscillator, an arrangement that allowed multiple power tubes to function as one in a transmitter and greatly increasing the power.
35.
On shared antenna sites, the bandpass duplexer variety is greatly preferred because this virtually eliminates interference between transmitters and receivers by removing out of band transmit emissions and considerably improving the selectivity of receivers.
36.
A duplexer must provide adequate rejection of transmitter noise occurring at the receive frequency, and must be designed to operate at, or less than, the frequency separation between the transmitter and receiver.
37.
Almost the same isolation as a low-grade duplexer ( about-60 decibels ) can be accomplished by installing the transmit antenna below, and along the centerline of, the receive antenna.
38.
This new system operated at 106 MHz ( 2.83 m ) and had simplifications of the antenna, elimination of lobe-switching, and the addition of a duplexer developed by Zahl.
39.
The duplexer is a device which prevents the repeater's high-power transmitter ( on the output frequency ) from drowning out the users'signal on the repeater receiver ( on the input frequency ).
40.
Europe s " second " digital dividend matches the second duplexer of the APT band plan which implies that the user equipment, as well as network elements will be compatible with those of the APT band plan.
