TM-9-1290-365-24-P
PALADIN MUZZLE VELOCITY SYSTEM M93 UPGRADED
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST
OCTOBER 2000
TM-9-1290-365-24-P - Page 286 of 334
ARMY TM 9-1290-365-24&P
D.9.2.5 DETAILED DESCRIPTION.
D.9.2.5.1 Transmitted Frequency and Power Tests. The transmitted frequency and power tests are per-
formed using a directional coupler and a variable attenuator. Those two components are connected
together during the tests because they are waveguide components and must be hardware connected.
This setup has waveguide-to-SMA adapters to provide easy connection to the unit under test (UUT) and
to other test equipment.
When the frequency counter is connected to the coupling output of the directional coupler, the trans-
mitted frequency is measured.
When the power meter is connected to the coupling output, the transmitted power is measured. The
power which enters the power meter is attenuated by the coupling attenuation of the directional coupler.
To get the real transmitting power, the coupling attenuation is added to the power measured by the power
meter. The equation for the transmitted power calculation is:
PT = Pt + Kp
where:
PT = transmitted power in dBm
Pt = measured power in dBm
Kp = coupling attenuation factor in dB
D.9.2.5.2 Receiver Sensitivity. The microwave section (including all adapters and SMA cables) is
installed permanently and is calibrated for its overall insertion loss. The overall insertion loss is due to
insertion losses of the components and reflection losses between components.
The receiver sensitivity is defined as the received (reflected) power required to achieve a signal at the
output of the transceiver which is 3dB greater than the noise level at the output when no signal is
received. The equation for the receiver sensitivity calculation is:
S = PT - Ks- 2A
where:
S = receiver sensitivity in dBm
PT = transmitted power in dBm
Ks = overall insertion loss factor in dB
A = attenuation of the variable attenuator in dB
The receiver sensitivity test is performed in 5 steps:
a. The output signal is adjusted to maximum reflected signal by the phase shifter.
b. The transmitted power is measured on the power meter.
c. The output noise level is measured on the RMS voltmeter.
d. The reflected signal is adjusted, using the variable attenuator, to get an output signal which is 3dB
greater than the noise level.
e. The receiver sensitivity is calculated using the above equation.
NOTE
The attenuation of the variable attenuator is multiplied by 2 because the signal is
attenuated twice, once when it is transmitted forwards and once again when it is reflected
backwards.
The transceiver is connected to the directional coupler. The transmitted power is measured through the
coupling output as described in paragraph D.9.2.5.l. The transmitted signal passes towards the modu-
lated PIN switch where it is reflected or absorbed by the dummy load (see paragraph D.9.2.4). The PIN
D-116
Back to Top
