请帮忙翻一下这一段
To facilitate the automatic tuning process in a receiver, a number of AFs shall be transmitted. Ideally the AF list
shall only comprise frequencies of neighbouring transmitters or repeaters. Two methods of transmitting AFs are possible.
AF method A is used for lists up to 25 in number and AF method B is used for larger lists. AF method B is also used where
it is required to indicate frequencies of generically related services
不要用GOOGLE 翻译。。。。