Chapter 3 79
Making EDGE (with GSM) Measurements
Making the Output RF Spectrum Measurement
• Ofs Freq List - accesses a menu to choose the offset frequency list.
Select a
Standard, Short, or Custom list as shown in the table below.
•
Offset Freq - Only available when Measure is set to Single Offset
(Examine). Offset frequencies can be entered using the RPG knob or
the Data Entry keys.
• Trig Source - in this measurement, trigger source and burst sync are
linked. Refer to the explanation under
Burst Sync.
•
Burst Sync - Synchronization is different on ORFS compared to other
measurements. Since offsets may be very low power and acquired
using very narrow filters, the burst edges are not well defined and
there certainly is not enough information to perform a
demodulation. Therefore all synchronization is performed on the
carrier. The timing reference (“T0”) is then re-used on the offsets.
Since “T0” on the carrier is determined with respect to the trigger
point, the trigger point on the offsets is very important. Once “T0” is
determined, the 50% and 90% points can be found.
List Modulation Offsets
(kHz)
Switching
Transients
Offsets
(kHz)
Standard 100, 200, 250, 400, 600,
800, 1000, 1200, 1400,
1600, 1800, 3000, 6000
400, 600,
1200, 1800
Short 200, 250, 400,
600 1200, 1800
400, 600,
1200, 1800
Custom User-defined list that specifies:
Offset Freq, RES BW, Limit Offsets,
Meas Type,
Initialized to be the same as the standard
list
(currently settable only by remote
commands)
400, 600,
1200, 1800
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