RF Receiver Overload test | Receiver maximum tolerable power test

This page covers RF receiver overload measurement basics. It mentions test setup used for receiver maximum tolerable power measurement verification and testing.

Often is is specified as following in test requirement of DUT (Device Under Test).

"The receiver should be capable of decoding a maximum on channel signal of -30dBm." OR

"The receiver should tolerate a maximum signal of 0dBm without damage."

This test will verify ability of the RF receiver to withstand maximum input power without affecting the normal functioning in the system.

Test setup used for receiver maximum power measurement

maximum tolerable signal test setup

The figure-1 depicts test setup used to determine maximum tolerable signal of the DUT. The equipments such as RF Signal generator or Sweep Oscillator,VSA(Vector Signal Analyzer) or RF Power Meter, Directional Coupler, Variable RF Attenuator are used for the measurement.

Following test procedure is followed:
➨Make the test setup as shown in the figure.
➨Set the nominal RF frequency and power output in the RF signal generator or sweep oscillator.
➨Verify that device under test(DUT) is functioning properly.
➨Increase the power level in signal generator or decrease the attenuation setting in the variable RF attenuator slowly and reach the maximum limit specified in the specification/standard.
➨After reaching the maximum limit (say 0 dBm), verify the normal functioning of the DUT. If the DUT is working fine at this maximum power level, it concludes that test has been passed.
➨In some DUTs, it is difficult to verify normal working functions as it requires DUT to have initial handshake to be completed. For example, mobile subscriber in GSM or WiMAX or Station(i.e. client) in WLAN. In GSM or WIMAX, subscriber need to synchronized with respective base station to verify proper system operation of it. Similarly in WLAN, client station need to be synchronized with the AP (Access Point) before we conclude that it is working properly. In order to have this testing, Base Station Emulator or Access point is used in place of signal generator/sweep oscillator.

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