Noise on Analog
Figure 1.1 illustrates discrete data transmission, which is the transmission of one message from a finite set of messages through a communication channel. A message sender at the transmitter communicates with a message receiver. The sender selects one message from the finite set, and the transmitter sends a corresponding signal (or “waveform”) that represents this message through the communication channel.
The receiver decides the message sent by observing the channel output. Successive transmission of discrete data messages is known as digital communication. Based on the noisy received signal at the channel output, the receiver uses a procedure known as detection to decide which message, or sequence of messages, was sent. Optimum detection minimizes the probability of an erroneous receiver decision on which message was transmitted.
This chapter characterizes and analyzes optimum detection for a single message transmission through the channel. Dependencies between message transmissions can be important also, but the study of such inter-message dependency is deferred to later chapters.
The messages are usually digital sequences of bits, which are usually not compatible with transmission of physical analog signals through a communication channel. Thus the messages are converted into analog signals that can be sent through the channel. Section 1.1 introduces both encoding and modulation to characterize such conversion of messages into analog signals by a transmitter. Encoding is the process of converting the messages from their innate form (typically bits) into vectors of real numbers that represent the messages. Modulation is a procedure for converting the encoder-output real-number vectors into analog signals for transmission through a physical channel.
Section 1.2 studies the theory of optimal detection, which depends on a probabilistic model for the communication channel. The channel distorts the transmitted signals both
The receiver decides the message sent by observing the channel output. Successive transmission of discrete data messages is known as digital communication. Based on the noisy received signal at the channel output, the receiver uses a procedure known as detection to decide which message, or sequence of messages, was sent. Optimum detection minimizes the probability of an erroneous receiver decision on which message was transmitted.
This chapter characterizes and analyzes optimum detection for a single message transmission through the channel. Dependencies between message transmissions can be important also, but the study of such inter-message dependency is deferred to later chapters.
The messages are usually digital sequences of bits, which are usually not compatible with transmission of physical analog signals through a communication channel. Thus the messages are converted into analog signals that can be sent through the channel. Section 1.1 introduces both encoding and modulation to characterize such conversion of messages into analog signals by a transmitter. Encoding is the process of converting the messages from their innate form (typically bits) into vectors of real numbers that represent the messages. Modulation is a procedure for converting the encoder-output real-number vectors into analog signals for transmission through a physical channel.
Section 1.2 studies the theory of optimal detection, which depends on a probabilistic model for the communication channel. The channel distorts the transmitted signals both