请高手用英语翻译这段通信相关内容，非常感谢

Modulation methods primarily through changes in the rate of sine wave, phase and frequency to transmit information. The basic principle is that the data signal carrier of the parasite in a parameter: magnitude, frequency and phase, which uses data signals for amplitude modulation, frequency modulation and phase modulation. Digital signal only a few discrete values, like using digital signal to control the choice of switching with different parameters of the oscillation, the digital signal for the modulation known as keying. Modulation into digital AM, FM and Phase three, the simplest way is to switch keying, "1" appears connected to the amplitude of the carrier A, "0" appears off-carrier, which is equivalent to primordium Signal (pulse out) spectrum moved to the carrier on both sides. If the carrier frequency by changing the method to send binary symbols, is the frequency shift keying (FSK) method, when the "1" when there is low frequency, "0"