General Instructions For Tx Troubleshooting - Nokia RH-6 Series Rf Description & Troubleshooting

Hide thumbs Also See for RH-6 Series:

Disassembly instructions manual (12 pages)

Baseband description & troubleshooting (72 pages)

Table Of Contents

Table of Contents

RH-6

7 - RF Description & Troubleshooting

The EGSM900 output is controlled by the power control loop. From the EGSM900 output

of the PA the RF signal is fed through the directional coupler (one of the power control

loop components) to the antenna switch.

GSM1800 and GSM 1900 TX path

The balanced TX signal from baseband is coming to the Mjoelner RF ASIC. The GSM1800

path of Mjoelner RF ASIC includes an common RF modulator for GSM1800 and

GSM1900. The BB signal is up-converted with the LO signal corresponding to the wanted

TX channel. The GSM1800/GSM1900 TX output of Mjoelner RF ASIC is a balanced signal.

From the balanced output of Mjoelner RF ASIC the signal is fed through the TX balun

(T701) (balanced to single ended) and a 3dB pad to the GSM1800/1900 input of the

power amplifier (PA).

The GSM1800/GSM1900 part of the PA has a maximum output of app. 33dBm. The sup-

ply is coming directly from the battery terminals.

The output is controlled by the power control loop. From the output of the PA the signal

goes through the directional coupler (one of the power control loop components) to the

antenna switch.

Antenna switch (TX/RX switch)

The antenna Switch works as a diplexer for the RX and TX signals. Moreover, it sup-

presses the TX harmonics generated by the PA. The antenna switch is controlled by the

Mjoelner RF ASIC using the control signals CONT1, CONT2 and CONT3.

The following table shows the possible different states.

CONT1

CONT2

[Volt]

2.7