 |
|||
|
|
|||
|
|
|||
| ||||||||||
|
|  (deenergized on transmit) to the control
Set Control C-1439/U is routed through
grids of V804 (fig. 14).
contacts 7 and 8 of switch S801A, capaci-
b. Resistors R815 and R807 form a volt-
tor C801, and terminal Z of plug P801 to
age divider that attenuates the input signal
the broadband encoding equipment. The en-
to the proper level. Capacitor C818 blocks
coding equipment returns coded audio sig-
the flow of dc current between the encoding
nal through terminal c of P801, resistor
equipment and the audio amplifier and mod-
R815, contacts 5 and 15 of tr relay K802
ulator subunit. The transmitted broadband
(energized on transmit), capacitor C818
signals are amplified and used to modulate
(loaded by R807) contacts 2 and 1 of S801B,
transmitter driver V105 and transmitter
contacts 13 and 3, and 1 and 20 of K802,
power amplifier V106 (para 55 and 56).
contacts 9 and 14 of squelch relay K801
Section Il. METERING CIRCUITS
b. The voltage drop across R1307 causes
a current to flow through M701 through the
following path:
Meter M701, together with S704, permits
(1) From R1307 through calibrating
measurements of all critical current and
resistor R1308.
voltage levels throughout the rt unit and the
(2) Terminal S of J7 and P701.
power supplies associated with Radio Set
(3) Contacts 11 and 12 of S704A.
AN/VRC-24 or Radio Set AN/TRC-68. The
(4) Meter M701 and current-limiting
various switch positions and the associated
resistor R701.
circuit components are covered in para-
(5) Contacts 12 and 11 of S704B to
graphs 67 through 76.
ground.
a. When METER switch S704 is in the
a. When METER switch S704 is in the
SWR position, Meter M701 indicates re-
PWR position, meter M701 indicates inci-
flected power on the transmission line from
dent power delivered to the antenna. Under
the antenna. The rectified voltage drop
normal operating conditions, the meter
across resistor R1307 is proportional to
will read upscale on the PWR position and
the reflected power on the antenna. Refer
nearly zero on the SWR position. When a
to paragraph 10 for a detailed discussion
mismatch is introduced, such as an open-
of the directional coupler.
circuited or short-circuited coaxial cable,
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals