AD6657 Analog Devices, AD6657 Datasheet - Page 23

• Manufacturer Part Number: AD6657
• Description: Quad IF Receiver
• Manufacturer: Analog Devices

Data Sheet
Figure 48 to Figure 50 show the typical spectrum that can be
expected from the AD6657 in the 33% BW mode for three
different tuning words.
–100
–120
–100
–120
–20
–40
–60
–80
–20
–40
–60
–80
Figure 49. 33% BW Mode, Tuning Word = 17 (f
0
0
0
0
Figure 48. 33% BW Mode, Tuning Word = 5
10
10
20
20
30
30
FREQUENCY (MHz)
FREQUENCY (MHz)
40
40
f
f
NSR 33% BW MODE, TW = 17
SNR = 71.2dB (72.8dBFS) (IN-BAND)
SFDR = 93.7dBc (IN-BAND)
S
I
N
50
50
f
f
NSR 33% BW MODE, TW = 5
SNR = 71dB (72.5dBFS) (IN-BAND)
SFDR = 92.5dBc (IN-BAND)
S
IN
=
=
=
184.32MSPS
=
140MHz @ –1.6dBFS
184.32MSPS
140MHz @ –1.6dBFS
60
60
70
70
S
/4 Tuning)
80
80
90
90
Rev. B | Page 23 of 32
MODE PIN
The MODE pin input allows convenient control of the NSR
feature. A logic low enables NSR mode and a logic high sets the
receiver to straight 11-bit mode with NSR disabled. By default,
the MODE pin is pulled high internally to disable the NSR.
Each channel can be individually configured to ignore the
MODE pin state by writing to Bit 4 of the NSR control register
at Address 0x3C. Use of the NSR control register in conjunction
with the MODE pin allows for very flexible control of the NSR
feature on a per-channel basis.
–100
–120
–20
–40
–60
–80
0
0
Figure 50. 33% BW Mode, Tuning Word = 27
10
20
30
FREQUENCY (MHz)
40
f
f
NSR 33% BW MODE, TW = 27
SNR = 71dB (72.5dBFS) (IN-BAND)
SFDR = 93dBc (IN-BAND)
50
S
IN
=
=
184.32MSPS
140MHz @ –1.6dBFS
60
70
80
AD6657
90