116Measuring Digital Communications SignalsMaking Adjacent Channel Power (ACP) MeasurementsMaking Adjacent Channel Power (ACP) MeasurementsThe adjacent channel power (ACP) measurement is also referred to as the adjacentchannel power ratio (ACPR) and adjacent channel leakage ratio (ACLR). We use theterm ACP to refer to this measurement.ACP measures the total power (rms voltage) in the specified channel and up to sixpairs of offset frequencies. The measurement result reports the ratios of the offsetpowers to the main channel power.The following example shows how to make an ACP measurement on a W-CDMAbase station signal broadcasting at 1.96 GHz. (A signal generator is used to simulatea base station.)Step Action Notes1 Set up the signalgenerator.a. Set the mode to W-CDMA.b. Set the frequency to 1.920GHz.c. Set the amplitude to−10 dBm.2 Connect the source RFOUTPUT to the analyzerRF INPUT as shown.3 Select the mode. • Press Mode, SpectrumAnalyzer.4 Preset the analyzer. • Press Mode Preset.5 Set the analyzer radiomode to W-CDMA as abase station device.a. Press Mode Setup, RadioStd, 3GPP W-CDMA,3GPP W-CDMA,b. Press Mode Setup, RadioStd Setup, Device (BTS).
