Table of Contents
Advertisement
On
011
Oulput
DUPLEX GEN
The MONITOR Image/Duplex switch controls th
positive or negative signal of the offset. As the offset
changes, the generate frequency changes to reflect the
new offseL On line I, enter the channel number to select
a frequency from the RF memory table. In DUPLEX
GEN mode, the Image/Duplex two-position toggle
switch controls the duplex frequency output for above
(High) or below (Low) the receive programmed frequen-
cy. In monitor mode, this switch selects the frequency of
the local oscillator injection above or below the pro-
grammed monitor frequency
to
remove image in-
terference. Enter either the PL or DPL code of the
duplex generate frequency. If an entry is made into the
PL location, the DPL display changes to a dash. If an
entry is made into the DPL location, the PL display
changes to a dash. Line
I I indicates the position of the
FUNCTION switch. Generate or Monitor mode deter-
mines the source of modulation available for system
analysis. It is either applied to the duplex generator or
recovered from the monitor receiver. Both positive and
negative readings autorange in three digits with full
scale from 10KHz to 100 KHz. The bargraph represents
modulation levels and provides a smooth nonranging
analog display on a full scale of 20 KHz FM.
also changes to maintain the displayed offset value
whenever a new monitor frequency is entered. The pro-
grammable duplex offset equals the generate frequency
+ / - the monitor frequency.
+ 100
ATTEN) 0
+2.06
+45.00 MHz
074.7750 MHz
DPL) 137
06) 029.7750
MHz
CAUTION
10.0'
l.rUI
'0
L:.
Antenna
o
DUPLEX GEN
DEV KHz
DPLX Monitor
DPLX Offset
DPLX Generate
PL) - - -
-2.06
-100
ANT
FIGURE 3-19.· DUPLEX GENERATOR
DISPLAY
FIGURE 3-18.
DUPLEX GENERATOR SECTION
CAUTION
80.01
"PUT
'OWl'
FIGURE 3-20.
RF MEMORY DISPLAY
RF(MHz)
PL (Hz)
DPL
09)
150.5200
- ' -
131
11)
823.7320
- ' -
226
12)
154.0000
063.0
13)
164.0000 TX
075.0
145.0000 TX
14)
164.5500 TX
003.2
174.5500 TX
• RF MEMORY
An internal nonvolatile memory stores and displays pro-
grammable RF frequencies and their corresponding PL
or DPL codes. Use the keypad and display cursor to
enter or ,change a frequency in the memory table. A fre-
quency remains in the table until it is changed. Once
programmed, the memory provides one button recall to
set the operating frequency and code for the preset fre-
quency. Figure 3-20 shows a typical RF Memory table
page. The display allows page numbers from 1 to 4.
When the page number is changed, the display changes
to reflect the information stored on the new page. Enter
all numeric values, except preset channel numbers, up to
a total of 32 entries .. Preset channels
are either simplex
or duplex. Select 0 to 16 duplex channels through special
function control code 77XY (table 3-3). Duplex chan-
• DUPLEX GENERATOR
The Analyzer provides an RF output that is offset in fre-
quency from the Monitor center frequency and en-
hances capability to service duplex radio equipment
such as repeaters, car telephones, and emergency
medical telemetry portables. The DUPLEX GEN Out-
put becomes the generate port for this mode while the
transceiver or antenna port becomes the monitor port.
Figure 3-18 shows the DUPLEX GENERATOR
On/Off toggle switch, Antenna and Output connectors,
located in the lower left-hand corner of the front panel.
The duplex generator operates over the full monitor fre-
quency range and provides frequency offsets from 0
MHz to
±
10 MHz programmable in 5 KHz steps and
the single fixed offset of ± 45 MHz. The duplex
generator has full internal and external FM modulation
capability, including voice simultaneous with audible
and subaudible tones. This modulation appears on the
RF coming off the DUPLEX GEN Output port which is
a separate -35 dBm (4 m V) RF output.
Figure 3-19 shows the DUPLEX (Monitor, Offset, Gen-
erate) display, channel number, and system monitor fre-
quency. Enter the channel number. The CRT displays
the appropriate frequency from the RF Memory table.
The system operating frequency changes as required. If
the channel number defines a duplex frequency pair, the
generate frequency of that pair displays on line 5. Line 3
shows the corresponding calculated offset. If the offset
exceeds
±
45 MHz or 0
±
10 MHz, the generate fre-
quency changes to reflect the offset that was displayed
before channel selection. For a new entry, the channel
number changes to a dash and the system operating fre-
quency changes as required. The generate frequency
RF MEMORY
PL) - - -
- -) 267.5673 MHz
DPL) 132
PAGE SEL) 2
"----./
3-10
Hide quick links:
Advertisement
Table of Contents
