1## Channels and modems 2 3To be able to emulate the system performance in different environments, with 4different modems and analog components, and with different tradeoffs of 5simulation speed and accuracy, this Phy allows to use exchangable channel 6and modem models. 7How a user selects then is described in 8[this page](https://babblesim.github.io/2G4_select_ch_mo.html) 9 10All a channel needs to do for this Phy to be able to load and use it is to 11implement the interface described in [channel_if.h](../src/channel_if.h) 12 13Similarly modems models would need to implement the interface described in 14[modem_if.h](../src/modem_if.h) 15