Abstract
Adjacent Channel Power Ratio (ACPR) is one of the many ways to measure distortion in active circuits. It is often used with spread spectrum signals. It is a measurement of the amount of signal, or power, in the frequencies adjacent to the primary signal. ACPR is usually defined as the ratio of the RMS power in the adjacent frequency channel (or offset) to the RMS power in the transmitted frequency channel.
ACPR is measured by measuring the amplitude of the carrier over its channel bandwidth, then measuring the amplitude of the power in the adjacent channel, and calculating the ratio of the two measurements. Several considerations are presented using WCDMA as our example. A measurement technique is provided.
ACPR on Cassini, Measurement Based, for Spread Spectrum Signals.pdf