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Line 1 displays the mode, function, and current oper-
ating frequency.
•
GENERATE MODE
Figure 3-12 defines a generate mode metering display.
To operate, place FUNCTION switch in Generate posi-
tion. Press a FUNCTION arrow key to select a signal,
--PM for example. From the keypad, enter the desired
frequency. The Gen/Mon Mtr and FM LED's il-
luminate and the CRT displays GENERATE FM and
the carrier frequency. Use RF Scan control to tune up or
down. Adjust deviation using the 1 KHz Level control.
The CRT displays a complete summary of all
parameters including carrier frequency, selected code,
RF level in volts and dBm (analog and digital), devia-
tion or percent modulation. The display is explained
here line-by-line.
I) GENERATE FM
•• ) 154.1250 MHZ
2) PL) 150.0
DPL) •••
FIGURE 3-13. RF SCAN CONTROL
Line 5 displays RF output level in volts rms and in dBm.
The voltage reading autoranges in three digits with the
symbols uV for microvolts and MV for millivolts. The
dBm reading appears in four digits with 0.1 dB resolu-
tion.
Line 2 displays the PL or DPL code associated with the
generate frequency. The system does not allow simul-
taneous PL and DPL.
If
the operator enters the PL
code, the DPL display changes to dashes. If he enters
the DPL code, the PL display changes to dashes. The
programmed PL or DPL applies to the carrier auto-
matically. Control its level with the Code Synthesizer
Level knob.
.
4)
5)
0.61 uV
RF LEVEL
-111.4 DBM
•
ANALOG SYNTHESIZER TUNING (AST)
Figure 3-13 shows RF Scan control for Analog Syn-
thesizer Tuning (AST). Manually scan through any fre-
quency
by rotating
the control
clockwise or
counterclockwise at the rate of 32 frequency steps per
revolution. The position of the display cursor in the fre-
quency reading determines the size of the step. If the
cursor is over the 100 Hz position, the step size is 100
Hz. If the cursor is over the 1 KHz position, the step size
is 1 KHz. All seven possible cursor positions provide a
scan range from 0.01 MHz to 999.9999 MHz. Use the
RF Scan control to perform a linear sweep to scan the
center frequency up or down. Switch to AM or FM
Monitor FUNCTION to aid in positive identification
and analysis of an input signal. Listen to the
demodulated output via the built-in audio amplifier and
speaker.
• RF SWEEP GENERATOR
Use the SWEEP FUNCTION modes to continuously
sweep the RF generator output, display bandpass filter
and cavity response, and to identify defective filter net-
works. In SWP FUNCTION, select sweep width in the
0.01-1 MHz or 1-10 MHz range. The Dispr/Sweep
vernier controls the sweep width within either range. At-
tach a demodulator probe (RTL-4075A) to the Vert!
Sinad/Dist general purpose input port and select Scope
mode. The scope's horizontal sweep tracks the sweep of
the output frequency, thus allowing a frequency domain
analysis of filters, RF front ends, and duplexers, etc.
o
+100
+4.74
-18.1 DB
o
DEV KHZ
DIST/SINAD
8)
12.4 PCT
9)
10)
-60
12)
-4.74
13)
_
14) -100
The distortion of an input signal applied to the multi-
purpose input jack displays in percent with 0.1 % resolu-
tion. SINAD displays in dB with 0.1 dB resolution. The
bargraph responds linearly to the SINAD reading,
originating at the left side at -60 dB SINAD and exten-
ding to the right side for SINAD values to 0 dB.
Lines 12, 13,
&
14 display the level of frequency modu-
lation applied to the system RF output. Positive and
negative readings autorange in
3
digits. The zero-
centered bargraph extends to the right and left of center
corresponding to the modulation level. The graph
responds in a modified logarithmic manner that pro-
vides a smooth nonranging analog display with a full
scale of
±
100 KHz FM.
15) The w'ord ANT appears only when the antenna in-
put on the front panel is enabled.
3-5
•
MONITOR MODE
The Analyzer monitors RF input energy from an an-
tenna or a transmitter to accurately determine the fre-
quency, power level, and modulation characteristics.
It
monitors signals from 0.01 MHz to 999.9999 MHz with
a center frequency settable in 100 Hz increments.
CAUTION
Even when it is not selected, the antenna port is coupled
to the transceiver port with
a
nominal 30 dB isolation.
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