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Reference interference level

Purpose of measurements—what it proves

Reference interference level tests the receiver’s ability to demodulate and decode

a GSM signal in the presence of an interfering signal. This ETSI specification

covers both co-channel and adjacent channel interference. For co-channel testing,

two GSM modulated signals are applied to the receiver. The wanted signal level is

9 dB above the interfering signal level.

For adjacent channel testing, two GSM modulated signals are applied to the

receiver. This time the interfering signal will be 200 kHz offset and 9 dB above

the wanted signal. The adjacent channel test is repeated at 400 kHz offset and

41 dB above the wanted signal.

Theory in pictures

Graphical view of limits and specifications

Channel Type Error Parameter Limit Value %

RACH FER 16

TCH/F9.6 BER 0.8

TCH/FS FER 6α

Class Ib RBER 0.4/α

Class II RBER 8

Co-channel rejection

Wanted signal –84 dBm

Interfering signal –95 dBm

Adjacent channel rejection

Wanted signal –84 dBm

Interfering signal –75 dBm + 200 kHz

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Agilent Technologies Switch/Measure Manual do Utilizador Página 31