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E-Gsm / Dcs Measurements; Transmitter Power And Ramp Profile; Phase / Frequency / Time Relationship; Receiver Bit Error Rate (Rx Sensitivity) - Mitsubishi Electric trium aria Service Manual

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E-GSM / DCS measurements

4.b.1 Transmitter Power and Ramp profile
These two are interrelated, since the power ramp shape and its final peak value is stored in EEPROM as
adjustment values.
The peak power output must lie within 3 dB of specification and be flat to within 0.5 dB over the active period.
The ramp profile is designed to give minimum harmonics, and hence it is important to ensure it is adhered to.
Power ramp profile must be checked on all frequencies (in practice channels 975, 37 and 124 for the 900 MHz
band and channels 512, 698 and 885 for the 1800 MHz band). In conclusion, the ramp must fit the mask at all
frequencies and all power levels. The mask is usually stored in the radiocommunication tester. The test will
also be available to cover the frequency and power range automatically.
4.b.2 Phase / Frequency / Time relationship
This is a test of the quality of the modulation including the IQ balance and the Gaussian filters. The phase of
the carrier changes according to the arrival of 1s and 0s. Phase error must not be more than 20° peak and 5°
4.b.3 Receiver Bit Error Rate (RX sensitivity)
The specification is a Bit Error Rate (BER) of better than 2.44% for an input signal : -102 dBm for the E-GSM
900 band, and –100 dBm for the DCS 1800 band. There should be no error for -90 dBm to -20 dBm input
signal. The maximum workable error rate is 13%.
It is important that BER and RX sensitivity is good since measures of RXLEV (from -103 to -41 dBm) and
RXQUAL (from 0 to 7) are reported back to the base station on the SACCH to assist in handovers and power
level control. Errors in reporting will lead to sub optimum uses of channel space, or interference to others.
4.b.4 Handover between E-GSM 900 AND DCS 1800 standards
The M4 dual band may handover from the E-GSM 900 band to the DCS 1800 band automatically. If the
subscribed network has frequencies in both bands, the M4 dual band will work either in 900 MHz or 1800 MHz
band depending on the availability of frequencies.
Version C
Date: 05/00
Level 2 Service Manual
Mitsubishi Electric Telecom Europe
ZA le Piquet, 35370 Etrelles
Phone: +33 2 99 75 71 00
Fax: +33 2 99 75 71 47