ADL5375ACPZ-R7 datasheet(27/36 Pages) AD

27 / 36 page

Data Sheet

ADL5375

Rev. C | Page 27 of 36

Using the AD9122 DAC For Carrier Feedthrough and

Unwanted Sideband Nulling

The AD9122 features an auxiliary DACs (Register 0x42,

dc offset adjustments (Register 0x3C through Register 0x3F)

that can be used to null the carrier feedthrough by applying the

dc offset voltage at each main DAC channels. Unwanted

sideband suppression can be done by adjusting the I/Q phase

(Register 0x38 through Register 0x3B) and DAC FS (Register

0x40 and Register 0x44) registers.

GSM/EDGE OPERATION

The performance of the ADL5375-05 in a Multi-Carriers

GSM/EDGE environment is shown in Figure 68 and Figure 69.

Figure 68 illustrates the 6 MHz offset noise floor of the

ADL5375-05 at the six carriers MCGSM/EDGE(8-PSK) operating

condition vs. output power, and Figure 69 demonstrates IMD

performance of the same six carriers MCGSM/EDGE(8-PSK)

for the ADL5375-05 at 950 MHz. It is configured, as shown at

Figure 65, for this measurement. The AD9122 is set at −3 dB

digital FS back off, FDATA = 368.64 MSPS, 2× interpolation, and

PLL and inverse sync off. Complex IF at 174.32 MHz is generated

at NCO of the AD9122 and fed into the ADL5375-05 through a

fifth order Butterworth filter. Special care must be taken not to

be affected by the noise power of images through proper DAC

setup at the selection of IF Frequency, FDATA, FDAC, and so on for

such a low IMD and noise level measurement. Be sure to load

clean LO signals and use equipment that allows enough

dynamic range capability and noise correction feature to

compensated the noise originated by equipment itself.

–73

–74

–75

–76

–77

–78

–79

–80

–81

–82

–83

–84

–22

–30

–28

–26

–24

OUTPUT POWER (1 CARRIER/100kHz) (dBm)

–104.0

–104.5

–105.0

–105.5

–106.0

–106.5

–107.0

–107.5

Figure 68. ADL5375-05 GSM/EDGE(8-PSK) 6 Carriers 6 MHz Offset Noise Floor

at 950 MHz vs Output Power(1 Carrier/100 KHz), LO Drive = 0 dBm

Figure 69. ADL5375-05 GSM/EDGE(8-PSK) 6 Carriers Adjacent and Alternate

Channel Power Performance at 950 MHz; Output Power(1 Carrier/100 KHz) =

−24.4 dBm LO Drive = 0 dBm

The performance of the ADL5375 in a GSM/EDGE environ-

ment is shown in Figure 70 and Figure 71.

Figure 70 illustrates the 6 MHz offset noise of the ADL5375-05

and ADL5375-15 vs. output power at 940 MHz. Figure 71

demonstrates how the 6 MHz offset noise is affected by variations

in LO drive level for both version of the ADL5375 at 940 MHz.

–99

–107

–106

–105

–104

–103

–102

–101

–100

–5

–4

–3

–2

–1

OUTPUT POWER (dBm)

ADL5375-15

ADL5375-05

Figure 70. GSM/Edge (8-PSK) 6 MHz Offset Noise at 940 MHz vs. Output

Power, LO Drive = 0 dBm

ADL5375ACPZ-R7 数据表(PDF) 27 Page - Analog Devices

ADL5375ACPZ-R7 数据表(HTML) 27 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

数据表下载