606 Chapter 17
W-CDMA Downlink Digital Modulation for Receiver Test
Configuring for Out-of-Synchronization Testing
6. Set the sweep time for 500 ms.
Press
Sweep > 500 > ms.
7. Select external triggering so the measurement begins when the DPCH DTX period starts.
Press
Trig > Ext Rear.
Configuring the DPCH DTX Gating Trigger Signal
One of the fundamental features within the ESG is the ability to generate trigger signals using the LF Output
function. In this procedure, we will use the LF Output function to create the DPCH DTX gating signal.
1. Press
LF Out > LF Out Source > Function Generator.
2. Press
LF Out Waveform > More (1 of 2) > Pulse.
3. Press
LF Out Period > 500 > msec.
In accordance with the 3GPP specifications, the UE will cease transmission within a certain amount of
time when the base station’s DPCCH power level decreases by a certain amount. Conversely, the UE
will again begin transmission within a certain amount of time once the DPCCH power level attains the
correct power level. With the ESG, this is simulated by creating a DTX period for the DPCH. The pulse
period time entered allows for a complete cycle where the UE should discontinue and then begin
transmission.
4. Press
LF Out Width > 200 > msec.
This is the approximate period of time in which the UE should detect that the ESG’s DPCH has
discontinued transmission, and then turn off its own transmission.
5. Press
LF Out Amplitude > 2.5 > Vp.
6. Press
LF Out Off On to On.
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