THEORY OF OPERATION
The block diagram of the I-Q Vector Modulator is shown in Figure 1. An RF signal incident on a 3 dB quadrature hybrid is divided into two equal outputs, with a 90° phase difference between them. The in-phase, or 0°, channel is designated the I channel and the Quadrature, or 90°, channel is designated the Q channel. Each signal passes through a biphase modulator which sets the 0° or 180° state and the attenuation level for both the I and Q paths. The outputs of the I and Q path are combined to yield the resultant vector which may fall anywhere within the bounded area shown in Figure 2. Any signal applied to the I/Q Vector Modulator can be shifted in phase and adjusted in amplitude by applying the following relationships:
- Let the desired attenuation level = X dB and the desired phase shift
- The normalized output voltage magnitude is given by:
- The values of the I and Q attenuator control inputs are then expressed as:
I = V cos θ
and
Q = V sin θ
Figure 3 shows the nominal value of I and Q vs. either digital word (Series 71) or analog voltage (Series 72). Thus, to achieve an attenuation level of 3 dB with a phase offset of 112.5° (with respect to 0 dB and 0° reference states) the values of I and Q can be calculated as follows:
V = 10–(3/20) = 0.707
I = 0.707 cos (112.5°) =–0.027
Q = 0.707 sin (112.5°) = +0.65
From Figure 3, the control inputs to yield the desired amplitude and phase are approximately:
Analog Units (72 Series) |
Digital Units (71 Series) |
I = 5.78 volts |
100101000000 |
Q = 2.84 volts |
010010001011 |
While these values for I and Q will yield an output signal whose amplitude and phase are close to the nominal values over the entire operating frequency range of the vector modulator, the use of an iterative measurement procedure will determine the I and Q inputs which exactly define the desired parameter at any selected frequency.
PERFORMANCE CHARACTERISTICS
MODEL |
7120/7220 |
7122/7222 |
7124/7224 |
7128/7228 |
FREQUENCY |
0.5-2.0 GHz |
2.0-6.0 GHz |
4.0-12.0 GHz |
6.0-18.0 GHz |
INSERTION LOSS |
13 dB |
11 dB |
12 dB |
12 dB |
VSWR (MAX) |
1.6:1 |
1.8:1 |
1.8:1 |
2.0:1 |
POWER HANDLING Without PERFORMANCE DEGRADATION |
+7 dBm |
+20 dBm |
+20 dBm |
+20 dBm |
SURVIVAL POWER (MAX) |
1W |
ABSOLUTE INSERTION PHASE ACCURACY VS. FREQUENCY (MAX) |
±15o |
VARIATION OF PHASE VS. TEMPERATURE (MAX) |
±0.1 deg./ oC |
ATTENUATION RANGE (MIN) |
20 dB |
VARIATION OF AMPLITUDE VS. TEMPERATURE (MAX) |
0.02 dB/ oC |
RESPONSE TIME (MAX) |
0.5 µsec |
POWER SUPPLY |
-12 to -15V @ 70 mA
+12 to +15V @ 70 mA
|
CONTROL INPUT |
|
71 SERIES |
12 bit TTL for both I and Q inputs |
72 SERIES |
0 to +10V DC for both I and Q inputs |
CONTROL INPUT IMPEDANCE |
|
71 SERIES |
40 µA max |
72 SERIES |
10 kohm |
ENVIRONMENTAL RATINGS - OPTION G09
Operating Temperature
Range .........................
|
-54°C to + 100°C |
Non-Operating
Temperature Range ...
|
-65°C to + 125°C |
Humidity ........................
|
MIL-STD-202F, Method 103B, Cond. B (96 hrs. at 95%) |
Shock .............................
|
MIL-STD-202F, Method 213B, Cond. B (75G, 6 msec) |
Vibration ........................
|
MIL-STD-202F, Method 204D,Cond.B (.06" double amplitude or 15G, whichever is less) |
Altitude ..........................
|
MIL-STD-202F, Method 105C, Cond. B (50,000 ft.) |
Temp. Cycling ...............
|
MIL-STD-202F, Method 107D, Cond. A, 5 cycles |
|
ACCESSORY FURNISHED
Mating power/control connector (Series 71 only) |
AVAILABLE OPTIONS
Option No. |
Description |
7
|
Two type K male RF connectors |
10
|
One type K male (J2) and one SMA female (J1) RF connector |
G09 |
Guaranteed to meet Environmental Ratings |
G12 |
RoHS Compliant |
G18 |
REACH Compliant
|
|
DIMENSIONS AND WEIGHT Series 71
SERIES 71 |
MODEL |
A |
B |
C |
D |
E |
F |
G |
H |
J |
7120 |
4.95±.03
(125,7) |
3.38±.03
(85,9) |
1.02
(25,9) |
4.75±.01
(120,7) |
3.12±.01
(79,2) |
2.62
(66,5) |
1.69
(42,9) |
2.47
(62,9) |
.73
(18,5) |
7122 |
3.25±.03
(82,6) |
3.25±.03
(82,6) |
.85
(21,6) |
3.05±.01
(77,5) |
3.00±.01
(76,2) |
1.63
(41,4) |
1.99
(50,5) |
1.63
(41,4) |
.64
(16,3) |
7124 |
1.83
(46,5) |
7128 |
3.00±.03
(76,2) |
3.00±.03
(76,2) |
.96
(24,4) |
2.80±.01
(71,1) |
2.75±.01
(69,9) |
1.50
(38,1) |
1.63
(41,4) |
1.50
(38,1) |
.76
(19,3) |
J3 PIN FUNCTION |
PIN |
FUNCTION |
PIN |
FUNCTION |
1 |
I-5 |
20 |
I-4 |
2 |
I-6 |
21 |
I-7 |
3 |
I-8 |
22 |
I-3 |
4 |
I-9 |
23 |
I-2 |
5 |
I-10 |
24 |
I-1 (LSB) |
6 |
I-11 |
25 |
I-12 (MSB) |
7 |
N/C |
26 |
N/C |
8 |
+12 to +15V |
27 |
N/C |
9 |
GND |
28 |
GND |
10 |
GND |
29 |
N/C |
11 |
-12 to -15V |
30 |
N/C |
12 |
Q-3 |
31 |
N/C |
13 |
Q-2 |
32 |
Q-4 |
14 |
Q-1 (LSB) |
33 |
N/C |
15 |
Q-5 |
34 |
N/C |
16 |
Q-6 |
35 |
Q-12 (MSB) |
17 |
Q-7 |
36 |
Q-11 |
18 |
Q-8 |
37 |
Q-10 |
19 |
Q-9 |
|
|
MODEL |
WEIGHT (APPROX) |
7120
7122
7124
7128 |
13 oz. (369 gm)
10 oz. (284 gm)
10 oz. (284 gm)
9 oz. (255 gm) |
|
DIMENSIONS AND WEIGHT Series 72
SERIES 72 |
MODEL
|
A |
B |
C |
D |
E |
F |
G |
H |
J |
7220 |
4.95±.03
(125,7) |
3.38±.03
(85,9) |
1.02
(25,9) |
4.75±.01
(120,6 |
3.12±.01
(79,2) |
1.68
(42,7) |
0.75
(19,1) |
1.75
(44,5) |
73
(18,5) |
7222 |
3.25±.03
(82,6) |
3.25±.03
(82,6) |
.85
(21,6) |
3.05±.01
(77,5) |
3.00±.01
(76,2) |
1.63
(41,4) |
1.99
(50,5) |
0.90
(22,9) |
.64
(16,3) |
7224 |
1.83
(46,5) |
7228 |
3.00±.03
(76,2) |
3.00±.03
(76,2) |
.96
(24,4) |
2.80±.01
(71,1) |
2.75±.01
(69,9) |
1.50
(38,1) |
1.63
(41,4) |
0.78
(19,8) |
.76
(19,3) |
MODEL |
WEIGHT (APPROX) |
7220
7222
7224
7228 |
13 oz. (369 gm)
10 oz. (284 gm)
10 oz. (284 gm)
9 oz. (255 gm) |