What are the characteristics of each of analog and digital transmission used in data communication?

Digital signal: a sequence of voltage pulses transmitted over a medium. A signal is a representation of the electrical signals in which data is transmitted. The electrical signal transmitted over a telephone line that varies continuously according to the strength and amplitude of the sound is called an analog signal, and the level of the analog signal varies continuously. The electrical signal generated in a computer is a voltage pulse signal that uses two different levels to represent a sequence of 0 and 1 bits, and this electrical signal is called a digital signal. Analog transmission, the system is relatively simple, sometimes may be directly mixed and loaded with high-frequency up to transmit on the line, weak anti-jamming ability, transmission speed is relatively slow. Digital transmission is loaded into the high-frequency signal to transmit, receive is the reverse process. The system is relatively more complex, strong anti-jamming ability is now widely used with cell phones and wireless communication systems, transmission speed is also relatively fast.