W3013 Indirect Quadrature Modulator
with Gain Control
Preliminary Data Sheet
November 1998
Error Vector Magnitude (EVM) Testing
Error vector magnitude (EVM) is estimated by feeding signals to the W3013 as described at the top of the
Electrical Characteristics table. A narrowband, sine-wave modulation output spectrum is shown in Figure 3.
0
–10
RELATIVE MAGNITUDE (dBm)
–20
–30
–40
–50
–60
–70
–80
–90
1441.60 1441.68 1441.76 1441.84 1441.92
1442
1442.08 1442.16 1442.24 1442.32
1442.40
L5
–82 dBm
L4
–81 dBm
L3
–61 dBm
L2
–72 dBm
CARRIER
LSB –50 dBm
–53 dBm
USB
–10 dBm
f
BB
= 80 kHz
f
LO1
= 178 MHz
f
LO2
= 1620 MHz
RF
OUT
= 1442.08 MHz
U2
–63 dBm
U3
–71 dBm
U5
U4
–77 dBm
–84 dBm
FREQUENCY (MHz)
Figure 3. W3013 Sine-Wave Modulation Output Spectrum
Data from this spectrum are used to estimate EVM by the formula:
EVM (%) = 100
•
[10
10
P(L5)/20
+ 10
P(L4)/20
+ 10
P(L3)/20
+ 10
P(L2)/20
+
+ 10
P(U5)/20
P(LSB)/20
+ 10
P(U2)/20
+ 10
P(U3)/20
+ 10
P(U4)/20
]/10
P(USB)/20
The data presented in the spectrum above would yield:
EVM (%) = 100
Ÿ
[79e–6 + 89e–6 + 891e–6 + 251e–6 + 2239e–6 + 708e–6 + 282e–6 + 63e–6 +
141e–6]/0.316e
= 1.5%
This approximates worst-case digital modulation results because the sine-wave modulation estimate assumes all
spurious outputs are in phase and adds their magnitudes as scalars. In addition, this estimate includes full-
amplitude measurements of spurious peaks that would appear in adjacent and alternate channels, where a
receiver would otherwise provide attenuation. The L3 third-order intermodulation peak and LSB (lower sideband)
are normally the unwanted output frequencies that dominate the EVM estimate.
6
Lucent Technologies Inc.
AGERE [ AGERE SYSTEMS ]
