AD8345
MODULATED WAVEFORM SETUP
WCDMA 3GPP
To evaluate the AD8345 with modulated waveforms, the setup
shown in Figure 38 is used. A Rohde & Schwarz AMIQ signal
generator with differential outputs is used to generate the
baseband signals. For all measurements, the input level on each
baseband input pin is 0.7 V 0.3 V peak. The output is
measured with a Rohde & Schwarz FSIQ spectrum/vector
analyzer.
To evaluate the AD8345 for WCDMA, the 3GPP standard is
used with a chip rate of 3.84 MHz. The plot in Figure 40 is an
ACPR plot of the AD8345 using Test Model 1 from the 3GPP
specification with 64 channels active.
–10
CH PWR = –10.95dBm
–20
–30
–40
–50
–60
–70
–80
–90
ACP UP = –52.51dB
ACP LOW = –52.41dB
PC CONTROL
AMIQ
IN
IP
QP
QN
IEEE
PC CONTROLLER
IP
QP
QN
CHARACTERIZATION
AD8345
IN
HP8648C
FSIQ
RFOUT
IEEE
LO
BOARD
–100
–110
ENBL
RF I/P
VOUT
IEEE
P1
CENTER = 380MHz
SPAN = 14.7MHz
SPECTRUM
ANALYZER
Figure 40. Typical AD8345 WCDMA 3GPP Output Spectrum
+15V MAX
COM
GSM
IEEE
+25V MAX
–25V MAX
To compare the AD8345 output to the GSM transmit mask, I
and Q signals are generated using MSK modulation, GSM
differential coding, a Gaussian filter, and a symbol rate of
270.833 kHz. The transmit mask is manually generated on the
FSIQ using the GSM BTS specification for reference. The plot in
Figure 41 shows that the AD8345 meets the GSM transmit
mask requirements.
HP3631
Figure 38. Test Setup for Evaluating AD8345 with Modulated Waveforms
CDMA IS95
To measure ACPR, the I and Q input signals used are generated
with Pilot channel (Walsh Code 00), Sync channel (WC 32), Paging
channel (WC 01), and six Traffic (WC 08, 09, 10, 11, 12, 13)
channels active. Figure 39 shows the typical output spectrum for
this configuration.
0
–10
–20
–30
–40
–50
–60
–70
–80
To perform EVM, Rho, phase, and amplitude balance
measurements, the I and Q input signals used are generated
with only the Pilot channel (Walsh Code 00) active.
–10
CH PWR = –12.41dBm
ACP UP = –72.9dB
ACP LOW = –72.9dB
–20
–30
–40
–50
–60
–70
–80
–90
–90
–100
CENTER = 900MHz
SPAN = 1MHz
Figure 41. Typical AD8345 GSM Output Spectrum
–100
–110
CENTER = 880MHz
SPAN = 7.5MHz
Figure 39. Typical IS95 Output Spectrum
Rev. B | Page 18 of 20
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