Level 2 Service Manual
GALAXY ASTRAL GEO-GEO WAP
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 are stored in
EEPROM as adjustment values.
The peak power output must lie within 3 dB of specification and be flat to within 0.5dB 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
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 or 5° RMS.
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 -100dBm 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 are good since measures of RXLEV (from -103 to -41 dBm)
and RXQUAL (from 0 to 10%) 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 use of channel space,
or interference to others.
4.b.4 Handover between E-GSM 900 and DCS 1800 stantards.
The M4 dual band may handover from the E-GSM 900 band to the DCS 1800 band automatically. If
the subscrided network has frequencies in both bands, the M4 dual band will work either in 900 MHz
or 1800 MHz band depending on the avaibility of frequencies.
Mitsubishi Electric Telecom Europe SA
ZA le Piquet 35370 Etrelles
Phone: +33 2 99 75 71 00
Fax: + 33 2 99 75 71 47