TM 11-6625-2575-14
to 1200 MHz in two bands. The low band covers
a. Transfer characteristic measurements.
500 kHz to 300 MHz, and the high band 300
MHz to1200 MHz. The output may be continu-
c. System flatness.
ously adjusted over an 80 dB range to 0.5 volt
rms into a 50-ohm load. Provision is made for
d. Insertion loss measurements.
the use of both internal and external frequency
e. Return loss measurements.
are provided at 1.0-, 10.0-, and 50.0-MHz inter-
f. Small signal analysis.
vals. The AN/USM-203A is used in the field test
g. Open and closed loop response.
video frequency equipment. It can be used as a
chirp radar simulator and for wideband testing.
and transmission characteristics.
The stability is sufficient for narrow band circuit
testing. A broad choice of sweep rates permits
j. High Q swept frequency cavity measure-
ternal graphic recorder. Provision is made for
ments.
external detection of rf signals, or an internal de-
k. Bandpass measurement-typical test set-up.
tector can be used. Front panel connectors are
available to permit external control of sweep
NOTE
rate, rf level, and frequency identification.
A typical test setup using the AN/
1-9. Description
A front view of the AN/USM-203A is shown in
are possible which use external leveling,
an external detector, a graphic re-
ceptacles are indicated by the front panel mark-
corder, or a combination of these op-
tions. BNC connectors and -50 ohm
for the power cord entrys, fuse, and external
coaxial cable are used in the external
drive connector. The AN/USM-203A is con-
circuit.
structed of an aluminum alloy frame consisting
of two side rails, a rear panel, and a backing
panel. The frame is assembled with threaded
fasteners and inserts. The aluminum front panel
is mounted to the frame and covers the backing
panel. Printed circuit assemblies are mounted
to the aluminum frame. Aluminum slide panels
(dust covers) protect the sides, the top, and the
bottom of the AN/USM-203A. Aluminum sur-
faces are anodized.
Sweep frequency measurement techniques are
used to measure the characteristics of devices
which operate at high frequencies, and whose
response must be determined over a broad range
of frequencies. If a device or system contains
sweep frequency range of the AN/USM-203A, a
1-11. Technical Characteristics
display can be obtained which shows the reso-
nance peaks or depressions in the passband of in-
Center frequency range Continuously variable from 500
kHz to 1200 MHz in two
ranges.
passive. or active devices can be tested. The fol-
Range:
lowing list of potential applications will suggest
vhf . . . . . . . . . . . . . . . Continuously variable from 500
the range of utility of the AN/USM-203A.
kHz to 300 MHz.