Selecting The Lo Source - Agilent Technologies 85301B Configuration Manual

In Figure 7, the range uses a single-reflector CATR
to collimate the transmit beam to a plane wave.
In this case, the transmit source, LO source, the
85309A LO/IF unit and GPIB extender are located
in the positioner/feed pit. The 8530A, positioner
controller and computer system are located in the
control room.
Antenna
Under Test
85320A
Test
Mixer
Module
85320B
Reference
Mixer Module
37204A
GPIB
Positioner
Extender
Pit
Figure 7. Indoor range using single-reflector CATR
A dual-reflector CATR range is configured slightly
differently (Figure 8). The transmit source is located
in the control room with the 8530A. If the reference
mixer module will not reach the transmit source
due to cable length restrictions, the coupled refer-
ence signal can be routed to the reference mixer
module using coaxial cable.
Antenna
Under
Test
85320A
Test Mixer
Module
37404A
GPIB
Extender
Positioner
Pit
LO Source
Figure 8. Indoor range using dual-reflector CATR
12
Reflector
Transmit
Feed
RF Source
85309A
LO/IF Unit
Reference and
Test IF Signals
To Control
LO Source
Room
GPIB Extender
Cable
Subreflector
Reflector
Transmit
Feed
85320B
Reference
Mixer
RF Source
37204A
GPIB
Extender
8530A
85309A
LO/IF Unit
In all configurations, the cable lengths between the
85309A LO/IF distribution unit and the reference
and test mixers should be the same length. Mixer
power level is adjusted and leveled at the reference
mixer; using the same cable lengths for the test
mixer insures proper LO drive power to the test
mixer.

Selecting the LO Source

The 85301B antenna measurement system uses
synthesized RF and LO sources. Since the RF and
LO signals are synthesized, phase lock for the
receiver is unnecessary. Microwave mixers used
with the 85301B antenna measurement system use
fundamental mixing from 100 MHz to 18 GHz, and
harmonic mixing for frequencies above 18 GHz.
Thus, an LO source that operates over the frequency
range of 0.1 to 18 GHz will be adequate for all fre-
quencies of operation of the 85301B. A large selec-
tion of synthesized sources is available for LO
sources (refer to Table 1). However, because the
LO source only needs to operate over the frequency
range of 0.1 to 18 GHz, LO source selection can be
limited to the synthesizers shown in Table 5.
Table 5. Agilent 85301B LO sources
Model
Number Description
83620B 10 MHz to 20 GHz synthesized sweeper with
front panel controls.
Recommended Options: Option 004, rear-panel
RF output; Option 008, 1 Hz frequency resolution.
83622B 2 GHz to 20 GHz synthesized sweeper with
front panel controls.
Recommended Options: Option 004, rear-panel
RF output; Option 008, 1 Hz frequency resolution.
Control
83623B 10 MHz to 20 GHz synthesized sweeper with
Room
high output power, and front panel controls
Recommended Options: Option 004, rear-panel
RF output; Option 008, 1 Hz frequency resolution.
83624B 2 GHz to 20 GHz synthesized sweeper with
high output power, and front panel controls.
Recommended Options: Option 004, rear-panel
RF output; Option 008, 1 Hz frequency resolution.
Output
Power (dBm)
+ 13 dBm
+13 dBm
+17 dBm
+20 dBm