Download AD60100B QUADRATURE DEMODULATOR 6

AD60100B
QUADRATURE DEMODULATOR
6 - 10 GHz
FEATURES
LO/RF Frequency:
I/Q Bandwidth:
Input IP3:
Input P1dB:
Amplitude Imbalance:
Phase Error:
LO Power:
DC Supplies:
6 – 10 GHz
275 MHz
+22 dBm
+12 dBm
±0.1 dB
- 2 Degrees
+5 dBm
+5V @ 110 mA, -5V @ 40 mA
DESCRIPTION
Q
When a LO signal is applied, the AD60100B converts the
Q
I
I
RF input signal centered at the LO frequency directly to
baseband I and Q outputs. Integral low pass filters provide
I and Q anti-alias filtering. The AD60100B’s differential I
and Q outputs can be directly connected to 50  digitizers
or instrumentation.
The AD60100B can be easily interfaced with differential
high-speed analog-to-digital converters (ADCs). For more
LO
I/Q MIXER
information, please refer to the APPLICATIONS section of
this datasheet.
T Y P ICA L A P PL ICA TI ON: D IR ECT C ON VER S ION R EC E I VER
2-CHANNEL
DIGITIZER
(50 )
Q
I
I/Q MIXER
RF
LO
Pol yphase Microwave Inc.
1983 S Liberty Drive
Bloomington, IN 47403
USA
LNA
BPF
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2014 Polyphase Microwave Inc.
Tel: +1 (812) 323-8708
Fax: +1 (812) 323-8709
Web: www.polyphasemicrowave.com
RF
AD60100B
ELEC TR ICAL SPEC IFICATION S
T e s t C o n d i t i o n s : + 2 5  C , L O = + 5 d B m , R F i n p u t = + 0 d B m @ L O + 1 0 0 k H z u n l e s s o t h e r wi s e n o t e d .
PARAMETER
LO/RF Frequency Range
TEST CONDITIONS
1
MIN
TYP
6.0
MAX
UNITS
10.0
GHz
V
+5V DC Supply Range
+4.9
+5.0
+5.2
-5V DC Supply Range
-5.2
-5.0
-4.9
V
+5V DC Supply Current
110
mA
-5V DC Supply Current
40
mA
LO Power
+3
+5
LO VSWR
RF VSWR
+7
dBm
1.5:1
Ratio
2.5:1
Ratio
I/Q Baseband Filter Bandwidth
2
<1 dB Flatness
DC
275
MHz
I/Q Baseband Filter Stop Band
2
>25 dB Rejection
450
7000
MHz
±4
+8
mV
7
10
dB
I/Q Differential Output Impedance
100
I/Q DC Offset
-8
Conversion Loss
Noise Figure

7.5
dB
2-Tone, f = 1 MHz
+22
dBm
+12
dBm
LO-RF Isolation
No RF input drive
45
dB
LO-I/Q Isolation
No RF input drive
60
dB
Input IP3
Input P1dB
Amplitude Imbalance
-0.3
±0.1
+0.3
dB
Quadrature Phase Error
-6.0
-2.0
+2.5
Degree
Operating Temperature Range
-40
+85
ºC
+15
dBm
LO/RF Input Power w/o Damage
Notes:
1.
2.
W h e n R F > L O f r e q u e n c y: I  cos(), Q  sin()
Standard low pass filters. Contact factory for other options.
D IMEN SION DRAW ING
Pol yphase Microwave Inc.
1983 S Liberty Drive
Bloomington, IN 47403
USA



2014 Polyphase Microwave Inc.
Tel: +1 (812) 323-8708
Fax: +1 (812) 323-8709
Web: www.polyphasemicrowave.com
AD60100B
TYPICA L PERFORMANC E CHARAC TER ISTIC S
S t a n d a r d T e s t C o n d i t i o n s : + 2 5 C , L O = + 5 d B m , R F = + 0 d B m @ L O + 1 0 0 k H z .
LO-RF Isolation
12
60
10
50
8
40
Isolation (dB)
Conversion Loss (dB)
C o n ve r s i o n L o s s
6
4
30
20
10
2
0
0
6
7
8
9
6
10
7
8
Am p l i t u d e I m b a l a n c e
Quadrature Phase Error
0.6
6
0.4
4
9
10
LO Frequency (GHz)
LO Frequency (GHz)
DC Offsets
8
I
0.2
0.0
-0.2
-0.4
Q
4
2
DC Offset (mV)
Phase Error (Degrees)
Imbalance (dB)
6
0
-2
7
8
9
LO Frequency (GHz)
Pol yphase Microwave Inc.
1983 S Liberty Drive
Bloomington, IN 47403
USA
10
-2
-6
-8
-6
6
0
-4
-4
-0.6
2
6
7
8
9
LO Frequency (GHz)
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2014 Polyphase Microwave Inc.
10
6
7
8
9
LO Frequency (GHz)
Tel: +1 (812) 323-8708
Fax: +1 (812) 323-8709
Web: www.polyphasemicrowave.com
10
AD60100B
I/Q DEMODULATION
APPLICATIONS
The AD60100B converts an RF signal centered at
L O In put D r i ve R equ ir e me nt s
the LO frequency into I and Q baseband outputs. To
The AD60100B requires an LO signal be applied at
understand the process of I/Q demodulation, first
+5 dBm nominal to demodulate the RF input. If the
consider the case of an ideal demodulator. The
LO is pulsed, the I and Q outputs will be valid
original RF signal is defined using the complex
approximately 15 ns after the LO pulse is applied.
envelope representation:

z(t )  R A(t )e j ( 2f c t  ( t ))
Interfacing w ith D if ferent ial ADCs

(1)
is the real time-domain signal present at the
The AD60100B’s differential I and Q outputs can be
z(t )
interfaced with differential high-speed analog-to-
RF port of the demodulator centered at frequency
digital converters (ADCs). The AD60100B’s I and Q
outputs
are
DC-coupled
with
a
f c . z(t )
common-mode
 (t )
voltage of 0 V (ground). Most ADCs have a positive
has amplitude
in radians. Both
R
dependent.
0.8 V and 2.5 V.
of the expression.
signals,
voltage. Figure 1 shows the AD60100B interfaced to
0.1 uF
 (t )
are time-
taking only the real part
I (t )
and
Q (t ) :
(2)
where
ADC
A(t )  I 2 (t )  Q 2 (t )
INBN
Q
and
z(t )  I (t ) cos(2f ct )  Q (t ) sin(2f ct )
a dual ADC with differential inputs.
AD60100B
in volts and phase
can be written in terms of two orthogonal
z(t )
the I and Q signals to the ADC’s common-mode
A(t )
 denotes
input common-mode voltage requirement between
Series DC blocking capacitors can be used to float
A(t )
(3)
and
 (t )  arctan(Q (t ), I (t ))
0.1 uF
An ideal quadrature demodulator extracts the
INBP
Q
and
Q (t )
introduces
I (t )
signals defined in (2). A real demodulator
several
linear
distortions
including
conversion loss, amplitude imbalance, quadrature
0.1 uF
I
(4)
INAN
phase error, I-axis phase rotation, and I/Q DC
offsets. After applying these linear distortions, the
real measured I and Q output signals are obtained:
0.1 uF
I
Iˆ(t )  C I (cos  R I (t )  sin  RQ (t ))  BI
INAP
(5)
Qˆ (t )  CQ (cos  R cos  E Q (t )  sin  E I (t )  sin  R I (t ))  BQ
(6)
Figure 1. Differential ADC Interface
Pol yphase Microwave Inc.
1983 S Liberty Drive
Bloomington, IN 47403
USA



2014 Polyphase Microwave Inc.
Tel: +1 (812) 323-8708
Fax: +1 (812) 323-8709
Web: www.polyphasemicrowave.com
AD60100B
CI
is the I channel conversion loss factor,
the Q channel conversion loss factor,
I-axis phase rotation in radians,
DC offset in volts,
E
volts, and
radians.
BQ
BI
R
CQ
Quadrature phase error and DC offsets are also
is
obtained from the typical performance plots at 6
is the
GHz:
is the I channel
 E  0.5Deg .  0.0087 Radians
is the Q channel DC offset in
is the quadrature phase error in
When the LO and RF frequencies are not equal,
BQ  0.002V
BI  0.0025V
The next step in estimating
R
calculate the ideal
can be set to 0 to simplify (5) and (6):
(13)
I (t )
Iˆ(t )
and
(14), (15)
and
Qˆ (t )
is to
from the RF
Q (t )
input signal. Given that the RF signal frequency is 1
Iˆ(t )  C I I (t )  BI
(7)
kHz greater than the LO frequency,
I (t )
and
Q (t )
define an upper sideband tone of 1 kHz having a
Qˆ (t )  CQ (cos  E Q (t )  sin  E I (t ))  BQ
R
constant amplitude of:
(8)
is only important in applications when the phase
difference between the RF and LO signals must be
known (i.e. phase detector).
A2
(  2.0 )
 10 10
0.1
(16)
A  0.2512V
(17)
Example: Apply a 6 GHz CW LO signal at +5 dBm
From (3) and (17) we know:
and a 6.001 GHz CW RF signal at -2 dBm. To
estimate the AD60100B’s
Iˆ(t )
and
Qˆ (t ) signals,
I (t )  0.1776 cos(2 1000t )
start by determining all the parameters in (7) and
and
(8).
CI
and
CQ are
Q (t )  0.1776 sin(2 1000t )
determined by the conversion loss
and amplitude imbalance of the AD60100B. From
The final step in estimating
the datasheet’s typical performance plots at 6 GHz,
C I  CQ
2
20 log(
 10
CQ
CI
CI
( 7.5
20
)
and
CQ
C I  0.429
CQ  0.434
Pol yphase Microwave Inc.
1983 S Liberty Drive
Bloomington, IN 47403
USA
Qˆ (t ) , the
(7) and (8) giving the final result:
(9)
Iˆ(t )  0.0762 cos(2 1000t )  0.0025
(10)
)  0.1
and
insert (11), (12), (13), (14), (15), (18), and (19) into
:
 0.4315
Iˆ(t )
(19)
demodulator’s real I and Q outputs signals, is to
use 7.3 dB conversion loss and 0.1 dB amplitude
imbalance to find
(18)
Qˆ (t )  0.077 sin(2 1000t  0.0087)  0.002
(11), (12)



2014 Polyphase Microwave Inc.
Tel: +1 (812) 323-8708
Fax: +1 (812) 323-8709
Web: www.polyphasemicrowave.com