AD8349 datasheet(22/28 Pages) AD

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AD8349

Rev. 0 | Page 22 of 28

–140

–120

–110

–100

–90

–80

–70

–60

–50

–40

CH PWR = –23.2dBm

ADJ CPR = –60.7dBm

ALT CPR = –62.3dBm

–130

CENTER 1.96GHz

SPAN 50MHz

Figure 60. 4-Carrier WCDMA Spectral Plot at 2140 MHz,

Including ACPR and Alternate Channel Power Ratio

–67

–65

–63

–61

–59

–57

–55

–53

–36

–34

–32

–30

–28

–26

–24

–22

–20

–18

–16

CHANNEL POWER (dBm)

–152

–150

–148

–146

–144

–142

–140

–138

2140 ADJ CPR

2140 ALT CPR

2140 NOISE

1960 ALT CPR

1960 NOISE

1960 ADJ CPR

Figure 61. 4-Carrier WCDMA Adjacent and Alternate Channel Power Ratio

and 30 MHz Noise Floor (dBm/Hz) vs. BB Drive Level at 1960 MHz

and 2140 MHz

GSM/EDGE APPLICATION

Figure 62 and Figure 64 show plots of GMSK error vector

magnitude (EVM), spectral performance, and noise floor

(dBc/100 kHz at 6 MHz carrier offset) at 885 MHz and

1960 MHz. Based on spectral performance, a maximum output

power level of around 2 dBm is appropriate. Note, however, that

as the output power decreases below this level, there is only a

very slight increase in the dBc noise floor. This indicates that

baseband drive variation can be used to control or correct the

gain of the signal chain over a range of at least 5 dB, with little

or no SNR penalty.

Figure 63 and Figure 65 show plots of 8-PSK EVM, spectral

performance, and noise floor at 885 MHz and 1960 MHz.

An LO drive level of approximately –6 dBm is recommended

for GMSK and 8-PSK. A higher LO drive power will improve

the noise floor slightly; however, it also tends to degrade EVM.

–110

–90

–80

–85

–100

–70

–75

–60

–65

–50

–55

–95

–105

1.0

1.5

2.0

2.5

3.0

3.5

4.0

–2

–4

–8

–6

–10

CHANNEL POWER (dBm)

PEAK NOISE FLOOR

400kHz

600kHz

AVERAGE NOISE FLOOR

EVM

Figure 62.GMSK EVM, Spectral Performance, and Noise Floor

vs. Channel Power ( Frequency = 885 MHz)

–110

–90

–80

–85

–100

–70

–75

–60

–65

–50

–55

–95

–105

1.0

1.5

2.0

2.5

3.0

3.5

4.0

–6

–8

–12

–10

–14

–4

–2

CHANNEL POWER (dBm)

PEAK NOISE FLOOR

400kHz

600kHz

AVERAGE NOISE FLOOR

EVM

Figure 63. 8-PSK EVM, Spectral Performance, and Noise Floor

vs. Channel Power (Frequency = 885 MHz)

–110

–90

–80

–85

–100

–70

–75

–60

–65

–50

–55

–95

–105

1.0

1.5

2.0

2.5

3.0

3.5

4.0

–5

–7

–11

–9

–13

–3

–1

CHANNEL POWER (dBm)

PEAK NOISE FLOOR

400kHz

600kHz

AVERAGE NOISE FLOOR

EVM

Figure 64. GMSK EVM, Spectral Performance, and Noise Floor

vs. Channel Power (Frequency = 1960 MHz)

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