Maintenance; Scheduled Maintenance; Tcxo Adjustment; Fig. 5.1 Test Connection Of Tcxo Adjustment - R&S 4200 Series Operating Manual

Scheduled Maintenance

5

Maintenance

This chapter
Further
information
5.1 Scheduled Maintenance
Scheduled maintenance\Scheduled maintenance "Radio".doc
5.1.1

TCXO Adjustment

TCXO adjustment
This chapter provides information concerning scheduled maintenance and
cleaning.
Chapter 3.1 contains an overview of transceiver control elements,
indicators, etc.
Chapter 3 describes how to put the radio into operation.
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
D.U.T.
Fig. 5.1
Test procedure
DUT is controlled via the R&S ZS 4200 (see chapter 3.3).

 The minimum warm-up time is 1 minute for the TCXO.
 Test frequency:
Power level set:

 Mode:
 Radio is keyed ON, e.g. via function Test PTT, which delivers an
unmodulated CW signal (see chapter 3.4.7.4.1).
 Measure frequency at antenna X3 and adjust TCXO value using
the Service & Maintenance Tool R&S ZS 4200 (see chapter 3.3).
The step width (1 bit) for the 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 Δf ≤ ±0.2 ppm (corresponds to ± 24 Hz at 120 MHz)
ATT
X3
30 dB
Test connection of TCXO adjustment.
120 MHz (see chapter 3.4.7.2)
Low (see chapter 3.4.7.2)
AM (see chapter 3.4.7.2)
5.1
R&S XU 4200
Spectrum
analyzer/
frequency
counter
6166.5368.02.01