TM 11-6625-214-12
Table 3-1. Operating Controls and Indicators for AN/URM-52(*)
Control, indicator or connector
Function
PULSE RATE control
Determines pulse repetition frequency of internal pulse generating circuits when MOD
SELECTOR switch is set to INT, INT FM or SQ WAVE and SYNC SELECTOR switch
is set to either X1/PPS MUX 1 or X10 PPS/MUX 10. When SYNC SELECTOR
switch is set to X1/PPS MUX 1, pulse repetition rate is indicated directly on calibrated
dial of control when SYNC SELECTOR switch is set X10/PPS MUX 10, reading of
calibrated dial of control must be multiplied by 10 to indicate pulse repetition rate.
SYNCH SLECTOR switch
Determines type of synchronization that is to be employed when MOD SELECTOR switch
is set to INT/INTR, thus placing internal pulse modulation circuits in operation. SYNC
SELECTOR switch has following positions: (sine wave). In this position, and MOD
SELECTOR switch set to INT, signal generator may be synchronized by external sine
wave voltages with an amplitude between 5 and 50 volts rms, applied through SYNC
IN connector on front panel.
EXT -. This position, and MOD. SELECTOR switch set to INT, signal generator may be
synchronized by external negative pulses of an amplitude between 4 and 40 volts
peak, applied through SNCH IN connector on front panel.
EXT+. In this position, and MOD. SELECTOR switch set to INT, signal generator may be
synchronized external positive pulses with an amplitude between 4 and 50 volts,
applied through SYNC IN connector on front panel.
X1/PPS MUX 1. When in this position, and MOD SELECTOR switch is set to INT,
synchronization is by internal time base circuit. Repetition rate of rf output pulses
indicated directly by PULSE RATE control.
X10/PPS MUX 10. When in this position, and MOD SELECTOR switch is set to INT,
repletion rate of rf output pulses is 10 times rate indicated by PULSE RATE control.
POWER INPUT connector
Mates with primary power cable to provide power to signal generator.
FUSE 3 AMP/3.2 AMP LINE-SPARE
Primary power and spare fuses.
RF OUTPUT connector
Rf output signal is available at this connector.
EXT MOD connector
Enables signal generator to externally modulated.
SYNC IN connector
Enables signal generator to be externally synchronized.
SYNC OUT connector
Synchronizing pulses are available at this connector.
DELAYED SYNC OUT connector
Delayed synchronizing pulses are available at this connector.
DBM/POWER SET meter is exactly over ZERO SET
3-2.
Adjusting Output Level of Signal Generator
index line.
AN/URM-52(*)
d. Place MOD SELECTOR switch to CW.
Adjust POWER SET controls so that needle of
a. Allow the AN/URM-52(8) to warm up for 15
DBM/POWER SET meter rests on red line at center of
minutes with the MOD SELECTOR switch in CW
scale, 0 DBM.
position. If the ambient temperature is below about 10
e. Allow the equipment to stand for
C (50 F) , a longer warm-up period is required.
approximately 10 minutes with MOD SELECTOR switch
b. By means of signal frequency control, tune
on CW.
AN/URM-52(*) to desired frequency as indicated on
f.
Repeat c and d above following warm-up
MEGACYCLES dial.
period. When needle of meter remains on 0 DBM with
c. Turn MOD SELECTOR switch to OFF.
little or no deviation, AN/URM-52(*) has reached a
Adjust ZERO SET control so that needle of
stabilized temperature and is ready for use.
Section II. OPERATION UNDER USUAL CONDITIONS
because this adjustment establishes the reference levels
3-3.
Preliminary Starting Procedure
for the output power-monitoring system. This adjustment
For the purpose of the following adjustments, the
is essentially the same as that required to obtain CW
AN/URM-52(*) is assumed to be warmed up, adjusted
output.
for output reference level, and ready for operation at the
desired frequency, as described in paragraph 3-2.
3-5.
Operating Procedure.
External synchronizing and/or modulating equipment
should be turned on and allowed to warm up.
a. Adjusting Rf Section and Obtaining Cu
Output.
(1) Turn MOD SELECTOR switch to CW.
3-4.
Initial Adjustments
(2) Adjust OUTPUT ATTEN. Control to
Operating the signal generator can be divided into two
desired value of attenuation as indicated by output
parts:
Adjusting the rf section and adjusting the
attenuator dial under index window.
modulator section. In general, first adjust the rf section,
3-6
