Ericsson DUAL FORMAT MDX LBI-38848B, Руководство по обслуживанию

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AUDIO/LOGIC BOARD
The Audio/Logic Board provides all audio and digital
processing of the receive and transmit audio for digital
processing by the Logic Board. The board also contains
audio filtering, conventional analog tone processing, and the
receiver squelch. The Audio/Logic Board controls the opera-
tion of the radio and digitally processes the receive and
transmit audio. The board contains a microprocessor and
associated memory circuits including an EPROM for con-
trolling the processor and a programmable "personality"
memory (an Electrically Erasable PROM - EEPROM) to
store customer frequencies, tones and options. The micro-
processor provides control data to the Audio Signal Proces-
sor (ASP), conventional tone generation and detection,
frequency data for the synthesizer, and sends and receives
data to another microprocessor on the Display Board for the
LCD.
SYSTEM BOARD
The system board controls the main input power to the
radio. IGNITION SENSE input lead provides the necessary
signals to the MOSFET switching circuit. The board also
interfaces all option connections from the internal boards in
the radio with the optional items outside of the radio. All
external options for the radio, interconnect to the System
Board through the back of the radio using an optional cable.
FRONT CAP ASSEMBLY
The Front Cap Assembly contains the Audio Amplifier
Board. The Audio Amplifier Board provides compression of
the microphone audio. It also provides audio compression
for the received audio in the discriminator and internal/ex-
ternal speaker audio paths. A 10-watt power amplifier is
provided on the board to drive a 4-ohm internal/external
speaker.
ACCESSORIES AND OPTIONS
PC PROGRAMMER OPTIONS
The radio is programmed using an IBM compatible
personal computer equipped with a RS-232 port. Option
TQ3370 provides the RS-232 serial interface unit and the
cable between the PC and the unit. An auxiliary power
supply for the unit is also included but is not needed to
program the radio.
Option TQ3372 provides the radio programming cable
between the PC interface unit and the radio microphone jack.
MDX PC programming software Option TQ3346 (GE-
MARC only) or TQ3373 (EDACS) is provided in both 3.5
and 5.25 inch diskettes.
PC PROGRAMMED OPTIONS
Carrier Control Timer (CCT)
The Carrier Control Timer turns off the transmitter after
the microphone push-to-talk (PTT) switch has been keyed
for a pre-programmed time period. A pulsing alert tone
warns the operator to unkey and then rekey the PTT to
continue the transmission. The timer can be programmed,
using the PC programmer. Any time periods between 30
seconds and 7.5 minutes can be programmed in 30 second
increments. The timer can be enabled or disabled for each
channel.
Channel Guard
Channel Guard provides a means of restricting calls to
specific radios through the use of a Continuous Tone Coded
Squelch System (CTCSS), or a Continuous Digital Coded
Squelch System (CDCSS). Tone frequencies range from
67.0 Hz to 210.7 Hz in 0.1 Hz steps. There are 83 standard
PC programmable digital codes. The Channel Guard tone
frequencies and codes are software programmable. Both
tone frequencies and digital codes may be used. These codes
and frequencies are listed in Table 1 - Channel Guard Tone
Frequencies and Table 2 - Digital Channel Guard Codes.
Squelch Tail Elimination (STE)
STE is used with tone and digital Channel Guard to
eliminate squelch tails. The STE burst is transmitted when
the microphone PTT is released. The receiving radio decodes
the burst and mutes the receiver audio for 250ms. This mute
time allows the transmission to end and to mute the squelch
tail. The radio looks for STE on the received signal when the
microphone is either on or off-hook. The STE is enabled for
transmit and/or receive by PC programming the radio’s per-
sonality.
Retry Option
If no channel is free, the radio can be programmed to
activate the Call Retry state and display ’RETRYING’ in the
display. Retrying causes the radio to revert to Idle mode and
scan for an incoming call while trying to acquire a free
repeater approximately every 5 seconds for a 2 minute pe-
riod.
To reverse the polarity of the digital Channel Guard
codes in the PC programmer, type I ("inverted") before
the code number, i.e. I023.
NOTE
PRIMARY
CODE EQUIVALENT
CODE PRIMARY
CODE EQUIVALENT
CODE PRIMARY
CODE EQUIVALENT
CODE
023
025
026
031
032
043
047
051
054
065
071
072
073
074
114
115
116
125
131
132
134
143
152
155
156
162
165
172
174
205
223
226
243
244
245 340 766
566
374 643
355
375 707
520 771
405 675
301
603 717 746
470 701
640
360 721
327 615
534 674
060 737
173
572 702
605 634 714
273
333
366 415
233 660
517 741
416 553
354
057
142 270
135 610
350 475 750
104 557
267 342
176 417
370 554
251
261
263
265
271
306
311
315
331
343
346
351
364
365
371
411
412
413
423
431
432
445
464
465
466
503
506
516
532
546
606
612
624
627
631
236 704 742
227 567
213 736
171 426
427 510 762
147 303 761
330 456 561
321 673
372 507
324 570
616 635 724
353 435
130 641
107
217 453 530
117 756
127 441 711
133 620
234 563 621 713
262 316 730
276 326
222 457 575
237 642 772
056 656
144 666
157 322
224 313 574
067 720
161 345
317 614 751
153 630
254 314 706
075 501
037 560
231 504 636 745 632
565
654
662
664
703
712
723
731
732
734
743
754
036
053
122
145
212
225
246
252
255
266
274
325
332
356
446
452
454
455
462
523
526 123 657
307 362
163 460 607
363 436 443 444
344 471 715
150 256
136 502
235 611 671
447 473 474 744
164 207
066
312 515 663
076 203
137
535
525
253
536
542 653
661
425
655
652
550 626
433 552
521
467 511 672
524 765
513 545 564
533 551
472 623 725
647 726
562 645
NOTE:
Primary codes in bold are unique Ericsson codes.
Table 2 - Digital Channel Guard Codes
LBI-38848
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