AD8340ACPZ-REEL7 Просмотр технического описания (PDF) - Analog Devices

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AD8340ACPZ-REEL7

700 MHz to 1000 MHz RF Vector Modulator

Analog Devices 

Data Sheet

AD8340

BS, 1X, C0 : ADJ CHANNE L

REF –12dBm

OFFSET 0.5 dB

–20

*ATT 5dB

–30

–40

–50

*RBW 30kHz

*VBW 30kHz

*SWT 100ms

MARKER 2 [T1 NOI]

–148.76dBm/Hz

876.009615385MHz

CH PWR –5.17dBm

ACP LOW –60.94dB

ACP UP –60.08dB

ALT1 LOW –86.40dB

ALT1 UP –86.80dB

MARKER 1 [T1 NOI]

–148.89dBm/Hz

884.006410256MHz

LVL

NOR

–60

SWP 50 OF 50

–70

–80

–90

10

–50

0

POUT vs. VIN

–55

–10

–60

–20

ACP – 750kHz OFFSET, 30kHz RBW

–65

–30

–70

–40

–75

ACP – 1.98MHz OFFSET, 30kHz RBW

–50

–80

–60

NOISE – 4MHz OFFSET, 1MHz RBW

–85

–100

2

1

–110

CENTER 880MHz

1MHz/DIV

SPAN 10MHz

Figure 35. Output Spectrum, Single-Carrier CDMA2000 Test Model at −5 dBm

VI = VQ = 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.

–30

–30

–40

–40

–50

–50

–60

–60

ACP – 750kHz OFFSET, 30kHz RBW

–70

–70

–80

ACP – 1.98MHz OFFSET, 30kHz RBW

–80

–90

–90

NOISE – 4MHz OFFSET, 1MHz RBW

–100

–30

–25

–20

–15

–10

–5

0

OUTPUT POWER (dBm)

–100

5

Figure 36. Noise and ACP vs. Output Power,

Single-Carrier CDMA2000 Test Model, VI = VQ = 0.353,

ACP Measured in 30 kHz RBW at ±750 kHz and ±1.98 MHz Carrier Offset,

Noise Measured at ±4 MHz Carrier Offset

–70

0

–90

50 100 150 200 250 300 350 400 450 500

VI = VQ =VIN (mV)

Figure 37. Output Power, Noise, and ACP vs. I and Q Control Voltages,

CDMA2000 Test Model, VI = VQ, 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.

REF –15 dBm

*ATT 5dB

OFFSET 0.5dB

–20

–30

–40

–50

*RBW 30kHz

*VBW 300kHz

*SWT 5s

MARKER 1 [T1 NOI]

–148.83dBm/Hz

885.252403846MHz

CH1

–12.65dBm

CH2

CH3

TOTAL

–12.58dB

–12.87dB

–7.93dB

A

SOL

ACP LOW –61.41dB

ACP UP –61.87dB LVL

ALT1 LOW –82.36dB

ALT1 UP –81.92dB NOR

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. VI and VQ 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.

–60

–70

–80

–90

–100

1

–110

CENTER 880MHz

1.5MHz/

SPAN 15MHz

Figure 38. Output Spectrum, 3-Carrier CDMA2000 Test Model at

−12.5 dBm/Carrier, VI = VQ = 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

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