An Introduction to HD Radio Technology
1.1 What is HD Radio?
HD Radio is the trademark for iBiquity Digital Corporation’s in-band on-channel (IBOC) digital radio system. While there are differences between amplitude modulation (AM) and frequency modulation (FM) band HD Radio systems, an HD Radio signal can be generally described as a digitally modulated RF signal that is transmitted around, under and along side the present-day analog AM and FM signals. It should be noted that, strictly speaking, a hybrid HD Radio signal actually has two components – an analog modulated component (the legacy AM or FM signal) and the digitally modulated component referred to here. These digital signals are composed of multiple orthogonal frequency division ...