Spread spectrum. In telecommunication and radio communication, spread-spectrum techniques are methods by which a signal (e.g., an electrical, electromagnetic, or acoustic signal) generated with a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth.
Lipids are one of the four major groups of organic molecules; the other three being proteins, nucleic acids (DNA), and carbohydrates (sugars). Lipids are made up of the same elements as carbohydrates: carbon, hydrogen, and oxygen.
Lipids. Fats, oils, waxes, and sterols are collectively known as lipids. Like the carbohydrates, the true fats contain only carbon, hydrogen, and oxygen. The molecules of such a lipid are made up of a glycerol molecule with three fatty acid molecules attached to it. This kind of lipid is also called a triglyceride. An important class of lipids is composed of the phospholipids that make up cell membranes. The class of compounds called steroids are also lipids, and cholesterol is one of the steroids.