Register 6-If Fine Calibration Setup Register - Analog Devices ADF7021-V Manual

REGISTER 6—IF FINE CALIBRATION SETUP REGISTER
IRD1 IR_CAL_SOURCE ÷2
0 SOURCE ÷2 OFF
1 SOURCE ÷2 ON
IR_CAL_SOURCE_
IRC2 IRC1 DRIVE_LEVEL
0 0 OFF
0 1 LOW
1 0 MED
1 1 HIGH
CD7
0
0
0
.
.
1
•
A fine IF filter calibration is set by enabling the IF_FINE_
CAL bit (Bit DB4). A fine calibration is performed only
when Register 5 is written to and Register 5, Bit DB4 is set.
•
Lower Tone Frequency (kHz) =
XTAL
IF_CAL_LOW ER_TONE_DI
Upper Tone Frequency (kHz) =
XTAL
IF_CAL_UPP ER_TONE_DI
It is recommended that the lower tone and the upper tone
be set as shown in Table 24.
Table 24. IF Filter Fine Calibration Tone Frequencies
IF Filter Lower Tone
Bandwidth (kHz) Frequency (kHz)
9 78.1
13.5 79.4
18.5 78.1
IF_CAL_DWELL_TIME IF_CAL_UPPER_TONE_DIVIDE
UT8
UT7
0
0
0
0
0 0
. .
. .
0 1
IF_CAL_
... CD3 CD2 CD1 DWELL_TIME
0 0 1
... 1
... 0 1 0 2
... 0 1 1 3
. . .
... .
. . .
... .
1 1 1
... 127
Figure 68. Register 6—IF Fine Calibration Setup Register Map
×
VIDE 2
×
VIDE 2
Upper Tone
Frequency (kHz)
116.3
116.3
119
IF_CAL_UPPER_
UT3 UT2 UT1
... TONE_DIVIDE
0 0 1
... 1
0 1 0
... 2
... 0 1 1 3
... . . . .
... . . .
.
... 1 1 1
127
LT8
0
0
0
.
.
1
•
The IF tone calibration time is the amount of time that
is spent at an IF calibration tone. It is dependent on the
sequencer clock. It is recommended that the IF tone
calibration time be at least 800 μs.
IF Tone
The total time for a fine IF filter calibration is
IF Tone Calibration Time × 10
•
Bits[DB30:DB28] control the internal source for the image
rejection (IR) calibration. The IR_CAL_SOURCE_DRIVE_
LEVEL bits (Bits[DB29:DB28]) set the drive strength of the
source, whereas the IR_CAL_SOURCE ÷2 bit (Bit DB30)
allows the frequency of the internal signal source to be
divided by 2.
Rev. 0 | Page 51 of 60
IF_CAL_LOWER_TONE_DIVIDE
FC1
0
1
IF_CAL_LOWER_
LT3 LT2 LT1
LT7 ... TONE_DIVIDE
0 0 1
0 ... 1
0 1 0
0 ... 2
0 ... 0 1 1 3
. ... . . . .
. ... . . .
.
1 1 1 1
... 255
IF_CAL_DWE
=
Calibratio n Time
ADF7021-V
ADDRESS
BITS
IF_FINE_CAL
DISABLED
ENABLED
LL_TIME
SEQ CLK