Adjacent channel

As adjacent channel in telecommunications closest transmission channel is referred to the used transmission channel.

Example with UMTS

With UMTS z. B. for the FDD downlink the usable frequency of 2110 to 2170  MHz and a channel bandwidth of 5 MHz with a chip rate of 3.84 Mcps is specified. This results in a total of 12 downlink channels:

${\displaystyle {\frac {2170\,\mathrm {MHz} -2110\,\mathrm {MHz} }{5\,\mathrm {MHz} }}=12}$,

each channel has a bandwidth of 3.84 MHz and the center frequencies of the adjacent channels are 5 MHz apart.

In the ACP measurement, this specification is used to measure the power in the adjacent channels.