1
When GSM’s high and low bands come out from U1101, after a resistor attenuator
network, enter the U1207 from PIN3 and PIN4，then they come out again from U1207’s
PIN20 after they be amplified in it.
Figure 4 GSM high and low bands signals arrive J1203 after be amplified in U1207
GSM high and low bands signals after through the J1203, then through the RF cable and
arrive the J1203 which is on antenna subboard, then after through the antenna match
network，were radiated by the antenna.
Figure 5 GSM high and low bands signals arrive antenna subboard through the RF cable
2.
Rx path
GSM’s signal was received by antenna，and reach the J1203 on main board after through
the path on Figure 5 and the RF cable .Then the signal enter the U1207 from PIN20（path
on the figure 4 ‘s left part）。 GSM high and low bands signals were divided in U1207 and
came out from U1207’ PIN15 and PIN14 respectively , and then they arrived the saw
filter .The high band signal entered in U1206，The low band signal entered in U5605。
When they came out from the saw filter, they have become the differential signals .These
differential signals enter in the U1101 after they through the match network. The path
