Applied Signal Technology designs, develops, and manufactures signal processing equipment to collect and process a wide range of telecommunications signals for reconnaissance, certain industrial applications, and defense communications systems.

Since its inception in January 1984, the company has focused its efforts on signal processing equipment, but also provides specialized collection equipment, as well as complete signal processing systems.

The company completed its initial public offering of common stock in March 1993. The stock is traded on Nasdaq under the symbol "APSG".