Series 71, 12 Bit Digital and Series 72 Analog I-Q Vector Modulators

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Application Notes for Microwave Phase Shifter

Both Series comprise a family of four solid-state PIN diode I-Q Vector Modulators covering the frequency range from 0.5 to 18 GHz in four bands: 0.5 to 2 GHz, 2 to 6 GHz, 4 to 12 GHz and 6 to 18 GHz. See Fig. 1.

All models provide a full 360° range of phase shift and a minimum of 20 dB attenuation range at any frequency.

  • Simultaneous control of amplitude and phase
  • 0.5 to 18 GHz in four bands: 0.5 to 2 GHz; 2 to 6 GHz; 4 to 12 GHz; 6 to 18GHz
  • 12 Bit digitally programmable (Series 71)
  • Analog control (Series 72)
  • High speed
  • Guaranteed monotonicity

 


Series 71, 12 Bit Digital and Series 72 Analog I-Q Vector Modulators, rf iq vector modulator

Series 71 and 72 IQ vector modulator block diagram

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:


1. Let the desired attenuation level = X dB and the desired phase shift
     = θ° (with respect to 0 dB and 0° reference states).
2. The normalized output voltage magnitude is given by:
     ? V ? = 10?(x/20).
3. 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. 

 

I-Q phase relationship for series 71 and 72

 IQ Control characteristics 71 and 72 series vector modulators

 

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
72 SERIES

 


12 bit TTL for both I and Q inputs
0 to +10V DC for both I and Q inputs 

Control INPUT IMPEDANCE
71 SERIES
72 SERIES

 


40  µA max
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
G16 RoHS Plus REACH Compliant

 

DIMENSIONS AND WEIGHT Series 71 

Series 71 IQ vector modulator dimensions and weight

 

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)

 

 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)