Communications Engineering Portal

1Introduction

This portal introduces the foundations for transmitting information as physical signals and estimating that information at a receiver. The preceding software-engineering lecture addressed systems that can span multiple devices. Here, we explain the constraints imposed by channels, bandwidth, and noise when signals are transmitted between those devices.

2Learning Path

1. Relate time-domain signals to their frequency-domain spectra.
2. Analyze the effects of channels and filters through the frequency response of a linear time-invariant system.
3. Understand spectral translation by modulation and the meanings of signal-to-noise ratio and bandwidth.
4. Analyze spectral repetition and aliasing caused by sampling, and derive a reconstruction condition.

3Mathematical References

The Fourier transform connects time and frequency domains, while complex exponentials simplify calculations involving sinusoids and phase. Probability distributions describe noise probabilistically.