ISL5217KI Intersil, ISL5217KI Datasheet - Page 14

• Manufacturer Part Number: ISL5217KI
• Description: Up/Down Conv Mixer 2.5V 196-Pin BGA
• Manufacturer: Intersil

Specifications of ISL5217KI

• Package: 196BGA
• Maximum Power Dissipation: 1970 mW
• Operating Supply Voltage: 2.5 V

Carrier NCO
Following the interpolating filter section, the samples are
modulated onto a carrier signal via a complex multiply
operation. The Carrier NCO provides the quadrature local
oscillator references to the complex mixer.
The NCO has provisions for programming the frequency and
phase offset. The NCO has a 32 bit frequency control
providing sub-hertz resolution at the maximum clock rate.
The carrier NCO phase accumulator feedback can be preset
to synchronize multiple channels. The carrier NCO has a
32-bit 2’s complement programmable frequency increment
value which can range from -2
range of -f
frequency will range from -52MHz to +52MHz.
The maximum error is 104MHz/(2
carrier frequency can be calculated from the value loaded
into Control Address 0x8 and 0x9 by:
F
FIGURE 13B. INTERPOLATION FILTER IMPULSE RESPONSE
FIGURE 13C. INTERPOLATION FILTER IMPULSE RESPONSE
CARRIER
-100
-120
-0.05
-0.15
-0.25
-0.35
-0.45
-0.55
-0.65
-20
-40
-60
-80
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
0
0
INTERPOLATION FILTER RESPONSE
CLK
=
64
CR 31:0
L = 16; FOUT = 4096
L = 16; FOUT = 4096
/2 to
8
(
128
~
16
f
CLK
)
×
INTERPOLATION FILTER RESPONSE
192
f
/2. For f
CLK
SAMPLE TIMES
24
SAMPLE TIMES
14
×
31
256
2
–
to ~2
CLK
32
32
32
) = 0.0242Hz. The
320
= 104MHz, the
31
40
for a NCO output
384
48
448
56
(EQ. 5)
512
64
ISL5217
where CR(31:0) is the 32-bit frequency control word which
can range from -2
-f
This NCO frequency range allows for spectral inversion.
Given a desired carrier frequency, the value for CR(31:0)
loaded into the part can be calculated by:
where INT[X] is the integer part of the real number X.
The vector rotation can also be controlled by the sign of the
CF value. When CF is a positive value a counterclockwise
vector rotation is produced. When CF is a negative value a
clockwise vector rotation is produced.
The carrier frequency is loaded 16 bits at a time into Control
Words 8 and 9.
0x8, bits 15:0 = CF (31:16)
0x9, bits 15:0 = CF (15:0)
The 16-bit carrier phase offset initializes the most-significant
16-bits of the phase accumulator. The least significant 16
bits of the phase accumulator are cleared. Given a desired
carrier phase offset, the value CO(31:0) can be calculated by
the following equation.
The carrier phase offset is loaded into Control Word 0x7.
Control Word 7 (15:0) = CO (31:16).
Complex Mixer
The complex mixer multiplies the sin/cos terms generated by
the carrier NCO sin/cos generator with the I and Q
interpolated sample data. The mixers can be bypassed by
programming the carrier frequency to zero. This action sets
the sin/cos terms generated by the carrier NCO to 0 and 1
respectively. The block diagram of the Carrier NCO/Complex
Mixer is shown in Figure 14.
CR 31:0
CO 31:0
FIGURE 14. VECTOR MODULATOR/MIXER BLOCK DIAGRAM
CLK
(
EN OUT
EN OUT
(
Q(20:0)
Q(20:0)
I(20:0)
I(20:0)
/2 to
COS
COS
SIN
SIN
)
)
=
=
~
INT F
f
INT
CLK
19
19
19
19
[
(
-------------------------------------------- - *2
/2. f
C
PhaseOffset
31
⁄
f
CLK
CLK
to ~2
360°
*2
is the CLK frequency.
31
∑
∑
32
+
+
+
]
for a NCO output range of
-
)°
32
]
Im (20:0)
Re (20:0)
July 8, 2005
(EQ. 7)
FN6004.3
(EQ. 6)