Many wireless signals operate in a very crowded environment. Radio designers are very concerned about interfering signals, and intermodulations from these interfering signals. Specifically, radio designers are often concerned with interfering signals at the half-IF frequency. The half-IF frequency, when modulated with the LO, has a 2x2 intermod product that falls right on the IF frequency. For this reason, the 2x2 product is often used as a figure of merit for mixers in down-converting applications.