Chapter 1 Overview
Using the front and rear panels
WCDMA Options Version 6.20
11
Not all of the connectors may be fitted in your 4400. The connectors actually
available depend on your system configuration, in particular the installed system
options.
EXT SYNC — BNC socket. Input for external reference signal. If a high-precision
reference signal of 5 MHz, 10 MHz or 13 MHz is connected here, the internal
10 MHz reference signal of the 4400 will not be used.
Input level: approx. 0 dBm
Frequency tuning range: approx. 1 ppm (10E-6) (equals 10 Hz at 10 MHz)
Input resistance: approx. 50 Ω
10 MHz OUT — BNC socket. Output of the 4400’s internal 10 MHz reference
signal. With the help of this output, the internal time base of the 4400 can be
used to synchronize external equipment.
This output is very useful if the optional oven-controlled oscillator (OCXO) is
installed. More information on the OCXO can be found in section Accessories and
options.
Output power: approx. +5 dBm
Output resistance: approx. 50 Ω
SYNC IN/OUT — BNC socket, providing a CMOS-TTL signal.
The signal on this connector allows the GSM-specific synchronization with
external units. The connector is currently configured as Sync out. The 4400
outputs its internally generated frame synchronization signal. This signal is TTL-
low for (downlink) time slots 0 to 2 and TTL-high for time slots 3 to 7.
TRIG IN — BNC socket, expecting a CMOS-TTL signal.
A trigger signal applied on this connector triggers all GSM-related RF measure-
ments. The 4400 allows you to select between triggering on the rising or falling
edge of the signal connected here.
The main application for this connector will be measurements in non-call mode
at very low power levels, e.g. asynchronous measurements.
TRIG IN 2 — BNC connector for future use.
TRIG OUT — BNC connector for future use.
AUX 1 — Reserved for later use. Please do not connect anything here.
AUX 2 — Reserved for later use. Please do not connect anything here.
NOTE
In GSM, the timing of up- and downlink is shifted by three time slots to avoid
that a mobile has to receive and transmit during the same time slot. The time
difference between the falling and the rising edge of the Sync out signal
reflects exactly that time shift.
NOTE
For GSM the 4400 can internally trigger its asynchronous measurements as
long as the RF power level transmitted by the mobile is above –30 dBm. Only
in case you are working with lower RF power levels, it is necessary to supply
an external trigger signal on this input.
To Next Page
Loading...
