Negative frequency

Negative frequency is a concept that arises in signal processing and communications, particularly in the analysis of signals in the frequency domain through techniques such as the Fourier transform. 1. **Signal Representation**: When a real-valued signal is transformed into the frequency domain using the Fourier transform, it can be represented by complex exponentials of the form \( e^{j \omega t} \), where \( \omega \) is the angular frequency. In this context, both positive and negative frequencies are present.