Nokia 7270 Service Manual
Issue 2 03/2005
COMPANY CONFIDENTIAL
13
Copyright © 2005 Nokia. All Rights Reserved.
Issue 2 03/2005
Nokia Customer Care
Figure 12: Measured Level Differencer
Rx band filter response GSM 900, GSM 1800 and GSM 1900
The Rx Band Filter Response Calibration is identical for the other GSM 900, GSM 1800, GSM
1900 bands. So the instructions of chapter Rx Band Filter Response GSM850 can be applied
correspondingly. Frequency and channel designations vary correspondingly to the band select-
ed according to the displayed windows in Phoenix.
1900 bands. So the instructions of chapter Rx Band Filter Response GSM850 can be applied
correspondingly. Frequency and channel designations vary correspondingly to the band select-
ed according to the displayed windows in Phoenix.
The limits are valid for all GSM bands.
■
RX channel select filter calibration
In the following the calibration of the Rx Channel Select Filter (BB-filter) inside the RF-ASIC is
described. It is performed by internal measuring of a proto-type filter. For this reason the cali-
bration has to be done only once. No RF signal generator is needed.
described. It is performed by internal measuring of a proto-type filter. For this reason the cali-
bration has to be done only once. No RF signal generator is needed.
- Set operating mode to local mode.
-
Select
→ Tuning (Alt-U)
- Select
→ Rx Channel Select Filter Calibration (Alt-H)
The setup should now look like this: