Agilent Technologies E4438C

636 Chapter 17
W-CDMA Downlink Digital Modulation for Receiver Test
W-CDMA Downlink Concepts
Figure 17-35 Noise Measurement Bandwidths
As shown in Figure 17-35, the noise signal is added to the W-CDMA signal across the entire W-CDMA
signal spectrum. The ESG gives you two ways to control the noise level. You can set the noise using either
E
c
/N
o
(energy per chip to noise power density ratio) or C/N (carrier power to noise power ratio). Any
adjustment to either noise parameter, E
c
/N
o
or C/N, will affect the other; they are not mutually exclusive.
E
c
/N
o
lets you set the noise power relative to the power of a channel, versus setting the noise relative to the
carrier power (C/N). For example, if you select the P-CCPCH (called a reference channel), the power level
of this channel is used in the ratio for E
c
/N
o
. Figure 17-36 shows the downlink channel selections for E
c
/N
o
and the channel reference fields.
AWGN 3.84 MHz Values
Flat Noise Bandwidth
AWGN 7.68 MHz Entries