User`s guide

Chapter 4 169
Functionality/Operation
GSM Measurements Selection
4. Functionality /
Operation
GSM Measurements Selection
It is worthwhile to consider which parts of the block diagram are being tested by
each measurement with the Test Set. The following table lists the relationships
between each test item, test step, or parameter of the Test Set and those related
parts expected, or likely, to be functioning. Depending on the tests, however, some
parts may be involved multiple times with more or less information. Pitfalls are
descriptive examples suggesting where further investigation may be helpful.
Table 4-1 GSM Tests vs. Related Parts
Test Item/Step/Parameter Functioning Parts Pitfalls
TX Camp On & Call Setup Micro-Processor Low TX power?
Battery connection Poor modulation?
Keyboard & Display Channel Synth. not on all channels?
Channel Coder Poor receiver gain or sensitivity?
SIM inserted
TX & RX
Specifying TCH & BCCH Channel Synthesizer Same ARFCN for BCCH & TCH?
Audio Echo Speaker & Microphone Channel Synth. not on all channels?
Audio Circuits
Speech Coder
Power Control Level RF Detector Unstable loop at some amplitudes?
Power Calibration Incorrect power vs. time burst shape?
Power Level Loop Power amplifier compensated?
Power Ramp Ramp Control Incorrect power vs. time burst shape?
PA Switch Timing Power amplifier compensated?
Power Level Loop
Phase & Frequency Errors I/Q Modulator Slight I/Q modulator imbalance?
Pre-mod Gaussian Filter Channel synthesizer spurious?
PA Distortion
Channel Synthesizer
Spectrum Monitor Channel Synthesizer Channel synthesizer spurious?
Pre-mod Gaussian Filter Slight I/Q modulator imbalance?
I/Q Mod. Adjustment