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Both signal and noise in communication can be regarded as random processes that vary with time. The random process has the characteristics of a random variable and a time function, and can be described from two different but closely related perspectives: ① the random process is a collection of in...

The communication method is the way that the two people talking to each other work together or send messages.  1. Simplex, half-duplex and full-duplex communication For point-to-point communication, according to the direction and time relationship of message transmission, the communication mode c...

In the digital communication system, the receiver receives sum of the transmitted signal and channel noise. The optimal reception of digital signals based on the “best” criterion with the smallest error probability. The errors considered in this chapter are mainly due to band-limited ...

Fig. 6-6 is a block diagram of a typical digital baseband signal transmission system. It is mainly composed of a transmission filter (channel signal generator), a channel, a reception filter, and a sampling decider. In order to ensure the reliable and orderly operation o...

A digital baseband signal is an electrical waveform that represents digital information, which can be represented by different levels or pulses. There are many types of digital baseband signals (hereinafter referred to as baseband signals). Figure 6-1 shows a few basic baseband signal waveforms, ...

Acknowledgment signals can be divided into energy signals and power signals according to their strengths. Power signals can be divided into periodic signals and aperiodic signals according to whether they are periodic or not. The energy signal is finite in amplitude and duration, its energy is fi...