R&S 4200 Series - Maintenance; Scheduled Maintenance

Scheduled Maintenance R&S XU 4200
5.1 6166.5368.02.01
5 Maintenance
This chapter
This chapter provides information concerning scheduled maintenance and
cleaning.
Further
information
Chapter 3.1 contains an overview of transceiver control element
s,
indicators, etc.
Chapter 3 describes how to put the radio into operation.
5.1 Scheduled Maintenance
Scheduled mai ntenance\Sc heduled mai ntenance "Radio ".doc
5.1.1 TCXO Adjustment
TCXO adjustment
Due to the natural aging of the crystal oscillator (TCXO), it is advisable to
check the frequency offset after the first year of operation and readjust it if
necessary. We recommend a further adjustment interval of 3 years in order
to ensure the specified frequency accuracy.
Test connection
Fig. 5.1 Test connection of TCXO adjustment.
Test procedure
 DUT is controlled via the R&S ZS 4200 (see chapter 3.3).

The minimum warm-up tim
e is 1 minute for the TCXO.
 Test frequency: 120 MHz (see chapter 3.4.7.2)

Power level set: Low (see chapter 3.4.7.2)

Mode:
AM (see chapter 3.4.7.2)

Radi
o is keyed ON, e.g. via function Test PTT, whi
ch delivers an
unmodulated CW signal (see chapter 3.4.7.4.1).
 Measure frequency at an
tenna X3 and adjust TCXO value using
the Service & Maintenance Tool R&S ZS 4200 (see chapter 3.3).
The step width (1 bit) for th
e adjustment is approximately 11 Hz. Adjust
it only in small steps and do not detune the TCXO to the extreme
positions, because the internal reference on the RF module could
unlock here. (CBIT error 0315, see chapter 4.2.1).
Nominal value
TCXO f 
±0.2 ppm (corresponds to ± 24 Hz at 120 MHz)
D.U.T.
X3
ATT
30 dB
Spectrum
analyzer/
frequency
counter