Data Sheet AD8340
L
V
L
NOR
S
P
AN 10MHz
1MHz/DIVCENTER 880MHz
–20
–40
–50
–60
–70
–80
–90
–100
–
110
MARKER 2 [T1 NOI]
–148.76dBm/Hz
876.009615385MHz
*RBW 30kHz
*VBW 30kHz
*SWT 100ms
*A
TT 5dB
BS, 1X, C0 : ADJ CHANNEL
REF –12dBm
04699-035
–30
CH PWR
AC
P LOW
ACP
U
P
ALT1 LOW
A
LT1 UP
–5.17dBm
–60.94dB
–60.08dB
–86.40dB
–86.80dB
MARKER 1 [T1 NOI]
–148.89dBm/Hz
884.006410256MHz
SWP 50 OF 50
2
OFFSET 0.5 dB
1
Figure 35. Output Spectrum, Single-Carrier CDMA2000 Test Model at −5 dBm
V
I
= V
Q
= 0.353 V, ACP Measured at 750 kHz and 1.98 MHz Carrier Offset,
Noise Measured at ±4 MHz Carrier Offset, Input Signal Filtered Using a
Cavity Tuned Filter (Pass Band = 4.6 MHz)
Holding the I and Q control voltages steady at 0.353 V, input
power was swept. Figure 36 shows the resulting output power,
noise floor, and adjacent channel power ratio. Noise floor is
presented as noise in a 1 MHz bandwidth as defined by the
3GPP2 specification.
04699-036
–30
–40
–50
–60
–70
–80
–90
–100
ACP – dBc (30kHz RBW)
–30 50–5–10–15–20–25
OUTPUT POWER (dBm)
–30
–90
–70
–60
–80
–50
–40
–100
NOISE – dBm @ 4MHz CARRIER OFFSET (1MHz RBW)
ACP – 750kHz OFFSET, 30kHz RBW
ACP – 1.98MHz OFFSET, 30kHz RBW
NOISE – 4MHz OFFSET, 1MHz RBW
Figure 36. Noise and ACP vs. Output Power,
Single-Carrier CDMA2000 Test Model, V
I
= V
Q
= 0.353,
ACP Measured in 30 kHz RBW at ±750 kHz and ±1.98 MHz Carrier Offset,
Noise Measured at ±4 MHz Carrier Offset
The results show that at an output power of 3 dBm, ACP is still
in compliance with the standard (<−45 dBc at 750 MHz and
<−60 dBc at 1.98 MHz). At low output power levels, ACP at
1.98 MHz, carrier offset degrades as the noise floor of the
AD8340 becomes the dominant contributor to measured ACP.
Measured noise at 4 MHz carrier offset begins to increase
sharply above 0 dBm output power. This increase is not due to noise.
but results from increased carrier-induced distortion. As output
power drops below 0 dBm, the noise floor drops towards −90 dBm.
With a fixed input power of 2.4 dBm, the output power was
again swept by exercising the I and Q inputs. V
I
and V
Q
were
kept equal and were swept from 10 mV to 500 mV. The
resulting output power, ACP, and noise floor are shown in
Figure 37.
04699-037
10
0
–10
–20
–30
–40
–50
–60
–70
OUTPUT POWER (dBm)
0 50 100 150 200 250 300
350 400 450 500
V
I
= V
Q
=V
IN
(mV)
–50
–55
–60
–65
–70
–75
–80
–85
–90
ACP – dBc (30kHz RBW)
NOISE – 4MHz CARRIER OFFSET – dBm (1MHz RBW)
P
OUT
vs. V
IN
ACP – 750kHz OFFSET, 30kHz RBW
NOISE – 4MHz OFFSET, 1MHz RBW
ACP – 1.98MHz OFFSET, 30kHz RBW
Figure 37. Output Power, Noise, and ACP vs. I and Q Control Voltages,
CDMA2000 Test Model, V
I
= V
Q
, ACP Measured in 30 kHz RBW at ±750 kHz
and ±1.98 MHz Carrier Offset, Noise Measured at ±4 MHz Carrier Offset
In contrast to Figure 36, Figure 37 shows that for a fixed input
power, ACP remains fairly constant as gain and phase are
changed (this is not true for very high input powers). The noise
floor still drops with decreasing gain, but it never reaches the
−90 dBm level shown in Figure 37.
Figure 38 shows the output spectrum for a 3-carrier CDMA2000
spectrum. Again, the signal being applied to the AD8340 is
filtered by a cavity-tuned filter with a −3 dB bandwidth of
4.6 MHz. To reduce distortion, the total output carrier power
was reduced to approximately −8 dBm (per-carrier power =
−12.6 dBm). Adjacent channel power ratios of −61 dBc (2 MHz
from center of spectrum) and −82 dBc (3.23 MHz from center
of spectrum) were measured. The noise floor, measured at
5.25 MHz carrier offset, is approximately −149 dBm/Hz (−89 dBm
in a 1 MHz bandwidth). While some dynamic range is lost due
to output power back-off, ACP stays approximately equal and
noise floor improves slightly.
SOL
LVL
NOR
SPAN 15MHz1.5MHz/CENTER 880MHz
–20
–40
–50
–60
–70
–80
–90
–100
–110
*RBW 30kHz
*VBW 300kHz
*SWT 5s*ATT 5dB
REF –15 dBm
MARKER 1 [T1 NOI]
–148.83dBm/Hz
885.252403846MHz
OFFSET 0.5dB
1
04699-038
–30
CH1
CH2
CH3
TO
TAL
ACP LOW
ACP UP
ALT1 LOW
ALT1 UP
–12.65dBm
–12.58dB
–12.87dB
–7.93dB
–61.41dB
–61.87dB
–82.36dB
–81.92dB
A
Figure 38. Output Spectrum, 3-Carrier CDMA2000 Test Model at
−12.5 dBm/Carrier, V
I
= V
Q
= 0.353 V, ACP Measured at 2 MHz and 3.23 kHz
Offset from Center of Spectrum, Noise Measured at 5.25 MHz Carrier Offset,
Input Signal Filtered Using a Cavity-Tuned Filter (Pass Band = 4.6 MHz)
Rev. C | Page 15 of 20
