For 3 MHZ radio frequency signal, said there were 3000000 every second wave, according to the amplitude modulation (am), you can say 3000000 information, whether can be understood as can transmit 3000000 bits of information, thus understood as the communication rate can be sent to 3 m, in consideration of factors such as error correction coding situation, should also can reach hundreds of k rate, and, in fact, only to a few k rate,
The above understanding is where there is a problem, to solve