Ericsson MDX LBI-39015, Руководство по обслуживанию

Страница: 8 / 16

6. Priority 1 Channel Programming:
•
Method 1 - Front programmable (default)
P1 is added to the scan list using the front control
panel.
•
Method 2 - Fixed P1 Option
P1 channel is PC programmed into the radio
personality.
•
Method 3 - SELECTED channel option:
The P1 channel follows the SELECTED channel.
Each time the scan function is turned on by
pushing the SCAN switch, the P1 channel will then
follow any changes in the SELECTED channel
assignment when the channel switches are pushed.
DETAILED SCAN OPERATION
The scan operation is controlled by the Audio /Logic Board
and provides for scanning any or all of up to 16 channels. The
scanned channels may be located anywhere within the fre-
quency band of the radio and can include two priority channels
(P1 and P2).
If desired, all 16 channels can be scanned with or without
priority level. When SCAN is enabled, scanning of the selected
channels starts immediately. Scan time is approximately 15 to
160 milliseconds per channel, depending upon whether Chan-
nel Guard has been programmed for a particular scan channel.
If a carrier is not detected, the scan time is 15 milliseconds. If a
carrier is detected and Channel Guard is programmed for the
channel, the scan time is 75-175 milliseconds, depending upon
how close the Channel Guard tone is to the desired tone. Typi-
cal value is less than 175 milliseconds.
Priority 1 (P1) and Priority 2 (P2) channels, if present, are
not part of the non-priority channel scan list (S1, S2, S3,...) and
are treated separately. If there is no activity on any of the
scanned channels, then the scan sequence is as shown in the
following example.
Example 1: (More than four Non-priority channels, i.e., six channels)
P1-P2-S6-S5-S4-S3-P1-P2-S2-S1-S6-S5-P1-P2-S4-S3-S2-S1-P1-P2-...
Example 2: (Four or less Non-Priority channels, i.e., three channels)
P1-P2-S3-S2-S1-P1-P2-S3-S2-S1-P1-P2-S3-S2-S1-P1-P2-S3-S2-S1-...
Therefore, the scan sequence is: Scan P1 and P2 pro-
grammed. Then scan up to four non-priority channels before
scanning P1 and P2 again. If more than four (4) non-priority
channels exist, then scan will wrap around, continuously scan-
ning four channels of the non-priority list between each P1, P2
scan sequence. If the number of non-priority channels is less
than or equal to four, then all non-priority channels will be
scanned between each P1, P2 scan.
As an added example, consider channels 1-8 to be scanned
channels, with P1 being channel 1 and P2 being channel 8. The
scanning order then would be:
Since it takes approximately 15 to 160 milliseconds to scan
each channel, then each Priority channel is sampled every 0.09
to 0.96 seconds and the non-priority channels are sampled at
least once every 0.12 to 1.28 seconds. If Channel Guard is pro-
grammed for a channel, but no carrier is detected, the scan time
for that channel is 15 milliseconds.
SCANNING (Stopped On A Valid SCAN Channel):
Once a carrier is detected, the channel display will indicate
that channel. If the channel is a non-priority channel and there
are no priority channels, then scanning is halted. If only a Pri-
ority 2 (P2) channel is present, then it is scanned every 5 sec-
onds if it has Channel Guard programmed and carrier is
detected and every second otherwise. If there is only a Priority
1 (P1) channel, then it is sampled every 2.5 seconds if it has
Channel Guard and carrier is detected and every 500 millisec-
onds otherwise. If there are P1 and P2 Priority channels, the
sample rate will vary.
In order to show the various scan conditions, the following
conditions are used:
CONDITION 1: P1 and P2 have Channel Guard Programmed
a. No carriers detected on P1 or P2
P1-P1-P2-P1-P1-P2-P1-P1-P2...
tb (time between samples) =500 msec
ts (time of sample) =32 msec
b. Carrier on P1 detected/wrong Channel Guard
P1-P2-P2-P2-P2-P2-P1-P2-P2-P2-P2-P2-P1...
tb=1 second
ts=32 msec for P2
75-175 msec for P2
c. Carrier on P2 detected/wrong Channel Guard
P1-P2-P1-P1-P1-P1-P1-P1-P1-P1-P1-P2-P1...
tb=500 msec
ts=32 msec for P1
75-175 msec for P2
d. Carrier on P1 and P2 detected/both wrong Channel
Guard
P1-P1-P2-P1-P1-P2-P1-P1-P2...
tb=2.5 seconds
ts=75-175 msec
e. Carrier on P1 and right Channel Guard
Stop scan, display P1
f. Carrier on P2 and right Channel Guard
Display P2, scan P1
P1-P1-P1-P1-P1-P1...
tb=500 msec
ts=32 msec
g. Carrier on P2 with right Channel Guard, car-
rier/wrong Channel Guard on P1
P1-P1-P1-P1-P1-...
tb=2.5 seconds
ts=75-175 msec
CONDITION 2: Priority 1 has Channel Guard
Programmed, Priority 2 does not.
a. No carriers detected on P1 or P2
P1-P1-P2-P1-P1-P2-P1-P1-P2-...
tb (time between samples) =500 msec
ts (time of samples) =32 msec
b. Carrier on P1 detected/wrong Channel Guard
P1-P2-P2-P2-P2-P2-P1-P2-P2-P2-P2-P2-P1-P2-...
tb=1 second
ts=32 msec for P2
75 -175 msec for P1
c. Carrier on P1 detected/right Channel Guard
Stop on P1, stop scan
d. Carrier on P2
Stop on P2, scan P1
P1-P1-P1-P1-...
tb=500 msec
ts= 32 msec
e. Carrier on P2 and P1 with wrong Channel Guard on
P1
Stop on P2, scan P1
P1-P1-P1-P1-P1-P1-...
tb=2.5 seconds
ts=75-175 msec
CONDITION 3: P2 has Channel Guard, P1 does not
a. No carriers detected on P1 or P2
P1-P1-P2-P1-P1-P2-P1-P1-P2-...
tb (time between samples) =500 msec
ts (time of samples =32 msec
b. Carrier on P2 detected/wrong Channel Guard
P1-P2-P1-P1-P1-P1-P1-P1-P1-P1-P1-P2-P1-...
tb=500 msec
ts=32 msec for P1
ts=32 msec
75-175 msec for P2
c. Carrier on P2 detected/right Channel Guard
Stop on P2, scan P1
P1-P1-P1-P1-P1-P1-...
tb=500 msec
ts=32 msec
d. Carrier on P1 detected
Stop on P1, stop scan
CONDITION 4: P1 and P2 with no Channel Guard
a. No carriers detected on P1 or P2
P1-P1-P2-P1-P1-P2-P1-P1-P2-...
tb (time between samples) =500 msec
ts (time of sample) =32 msec
b. Carrier on P2
P1-P1-P1-P1-P1-P1-...
tb=500 msec
ts=32 msec
c. Carrier on P1
Stop on P1, stop scan
PUBLIC ADDRESS OPTION
OPERATION
If the Public Address Option is present, the radio may be
used as public address amplifier. Press the programmed flex
key or scroll through the menu to select the PA option (Scan
must be off). The LED display will show "Pub Addr".
When the microphone is keyed, the radio no longer trans-
mits, but allows the microphone audio to feed the speaker.
Adjust the VOLUME for the desired level. Press the pro-
grammed flex key or scroll through the menu a second time
to disable the PA option. The display will return to normal
channel display. Changing channels or turning on Scan will
also turn the operation off.
The following conditions are shown while listening to
a Non-Priority channel. The "ts" is the "hole" or audio
blanking time in the signal being heard while the radio
is checking the priority channels for activity.
NOTE
LBI-39015 LBI-39015
7