Motorola Astro Digitalport Saber Detailed 68p81076c10 A Manual

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Notations Used in 
This ManualThroughout the text in this publication, you will notice the use of 
warnings, cautions, and notes. These notations are used to emphasize 
that safety hazards exist, and care must be taken and observed.
NOTE:An operational procedure, practice, or
condition, etc., which is essential to
emphasize.
You will also find in this publication the use of the asterisk symbol (*) 
to indicate a negative or NOT logic true signal.
CAUTION: Indicates a potentially hazardous sit-
uation which, if not avoided, ma
y result in 
equipment damage. To properly word a caution, 
first identify the gravity of the risk, then 
describe the nature of the risk, then tell the user 
how to avoid the risk, and finally communicate 
this risk clearly to the person exposed to the 
risk.
WARNING: Indicates a potentially hazardous 
situation which, if not avoided, could
 result in 
death or injury. To properly word a caution, first 
identify the gravity of the risk, then describe the 
nature of the risk, then tell the user how to avoid 
the risk, and finally communicate this risk 
clearly to the person exposed to the risk.
DANGER: Indicates an imminently hazardous 
situation which, if not avoided, will
 result in 
death or injury. To properly word a caution, first 
identify the gravity of the risk, then describe the 
nature of the risk, then tell the user how to avoid 
the risk, and finally communicate this risk 
clearly to the person exposed to the risk.
!
C a u t i o n
!
W A R N I N G
!
D A N G E R 
						

							3-1
General Overview of an 
ASTRO Digital SABER Radio
3
The ASTRO Digital SABER radio is a dual mode (trunked/
conventional), microcontroller-based transceiver incorporating a 
Digital Signal Processor (DSP). The microcontroller handles the 
general radio control, monitors status, and processes commands input 
from the keypad or other user controls. The DSP processes the typical 
analog signals and generates the standard signaling digitally to 
provide compatibility with existing analog systems. In addition it 
provides for digital modulation techniques utilizing voice encoding 
techniques with error correction schemes to provide the user with 
enhanced range and audio quality all in a reduced bandwidth channel 
requirement. It allows embedded signaling which can mix system 
information and data with digital voice to add the capability of 
supporting a multitude of system features.
The ASTRO Digital SABER radio is available in three models, which are 
available in the following bands; VHF (136-174MHz), UHF (403-
470MHz or 450-512MHz), and 800MHz (806-870MHz).
The ASTRO Digital SABER radio consists of:
•Vocoder/Controller (VOCON) Board
•Band-Dependent Transceiver Board
•Display/Keypad Assembly
•In secure models, a hardware, encryption module is also included.
It is advantageous to think of the vocoder/controller (VOCON) board 
as two separate functional units; a vocoder and a controller. The 
vocoder section consists of a Digital Signal Processor (DSP), Static-RAM 
(SRAM), FLASH program memory, audio power amplifier (audio PA), 
and a custom ABACUS/DSP support integrated circuit (ADSIC). This 
section handles all the analog and signaling functions previously 
accomplished with analog integrated circuits (ICs) by processing the 
signals digitally. In addition, it provides advanced digital signal 
processing functions which include digital modulation and voice 
encoding techniques while still maintaining compatibility with 
today’s analog radio systems. The controller section consists of a 
microcontroller with FLASH program memory, EEPROM, SRAM, and a 
custom IC; the SLIC. This section handles general radio control and 
ergonomics through the various user buttons, and rotary knobs. 
The transceiver is frequency dependent, and one transceiver exists for 
each of the bands; VHF, UHF (range 1 and 2), and 800MHz. The 
distinction with these transceivers is the incorporation of the ABACUS 
IC. The ABACUS is a digital IF/Discriminator which provides a true 
digital interface to the digital circuitry of the vocoder. 
						

							3-2
The display module is a two-line, liquid crystal display with associated 
circuitry. The display module is an integral part of the front cover 
keypad. This module utilizes chip-on-board technology and is not 
considered field repairable.
The available encryption module connects directly to the VOCON 
board and interfaces directly to the vocoder digital circuitry. It 
contains an independent microcontroller, and two custom ICs to 
perform digital, numerical, encryption algorithms.
Analog 
Mode of OperationWhen the radio is receiving, the signal comes from the antenna/
antenna-switch connector to the transceiver board, passes through the 
RX/TX switch and the receiver front end. The signal is then filtered, 
amplified, and mixed with the first local-oscillator signal generated by 
the voltage-controlled oscillator (VCO). The resulting intermediate 
frequency (IF) signal is fed to the IF circuitry, where it is again filtered 
and amplified. This amplified signal is passed to the digital back-end 
IC, where it is mixed with the second local oscillator to create the 
second IF at 450kHz. It is then converted to a digital bit stream and 
mixed a third time to produce a baseband signal. This signal is passed 
to the VOCON board through a current-driven differential output. On 
the VOCON board, the ADSIC (ABACUS DSP Support IC) digitally 
filters and discriminates the signal, and passes it to the digital-signal 
processor (DSP). The DSP decodes the information in the signal and 
identifies the appropriate destination for it. For a voice signal, the DSP 
will route the digital voice data to the ADSIC for conversion to an 
analog signal. The ADSIC will then present the signal to the audio 
power amplifier, which drives the speaker. For signalling information, 
the DSP will decode the message and pass it to the microcontrol unit.
When the radio is transmitting, microphone audio is passed from the 
audio power amplifier (PA) to the ADSIC, where the signal is digitized. 
The ADSIC passes digital data to the DSP, where pre-emphasis and low-
pass (splatter) filtering are done. The DSP returns this signal to the 
ADSIC, where it is reconverted into an analog signal and scaled for 
application to the voltage-controlled oscillator as a modulation signal. 
Transmitted signalling information is accepted by the DSP from the 
microcontrol unit, coded appropriately, and passed to the ADSIC, 
which handles it the same as a voice signal. Analog modulation 
information is passed to the synthesizer along the modulation line. A 
modulated carrier is provided to the RF PA, which transmits the signal 
under dynamic power control.
ASTRO Mode 
(Digital Mode) 
of OperationIn the ASTRO mode (digital mode) of operation, the transmitted or 
received signal is limited to a discrete set of four deviation levels. The 
receiver handles an ASTRO-mode signal identically to an analog-mode 
signal up to the point where the DSP decodes the received data. In the 
ASTRO receive mode, the DSP uses a specifically defined algorithm to 
recover information. In the ASTRO transmit mode, microphone audio 
is processed identically to an analog mode with the exception of the 
algorithm the DSP uses to encode the information. This algorithm will 
result in deviation levels that are limited to four discrete levels. 
						

							3-3
Transceiver Board 
OverviewThe receiver front end consists of a preselector, an RF amplifier, a 
second preselector, and a mixer. Both preselectors in the VHF and UHF 
radios are varactor-tuned, two-pole filters controlled by the 
microcontrol unit through the digital/analog (D/A) IC. On the 
800MHz receiver front end, these filters are fixed-tuned. The RF 
amplifier is a dual-gate, gallium- arsenide based IC. The mixer is a 
double-balanced, active mixer coupled by transformers. Injection is 
provided by the VCO through an injection filter. See Table 14 for local 
oscillator (LO) and first IF information.
The frequency generation function is performed by three ICs and 
associated circuitry. The reference oscillator provides a frequency 
standard to the synthesizer/prescaler IC, which controls the VCO IC. 
The VCO IC actually generates the first LO and transmit-injection 
signals and buffers them to the required power level. The synthesizer/
prescaler circuit module incorporates frequency-division and 
comparison circuitry to keep the VCO signals stable. The synthesizer/
prescaler IC is controlled by the microcontrol unit through a serial bus. 
Most of the synthesizer circuitry is enclosed in rigid metal cans on the 
transceiver board to reduce microphonic effects. 
The receiver back end consists of a two-pole crystal filter, an IF 
amplifier, a second two-pole crystal filter, and the digital back-end IC 
(ABACUS). The two-pole filters are wide enough to accommodate 
5kHz modulation. Final IF filtering is done digitally in the ADSIC.
The digital back-end IC (ABACUS) consists of an amplifier, the second 
mixer, an IF analog-to-digital converter, a baseband down-converter, 
and a 2.4MHz synthesis circuit to provide a clock to the ADSIC on the 
VOCON board. The second LO is generated by discrete components 
external to the IC. The output of the ABACUS IC is a digital bit stream 
that is current driven on a differential pair for a reduction in noise 
generation.
The transmitter consists of an RF PA IC that gets an injection signal 
from the VCO. Transmit power is controlled by two custom ICs that 
monitor the output of a directional coupler and adjust PA control 
voltages correspondingly. The signal passes through a RX/TX switch 
that uses PIN diodes to automatically provide an appropriate interface 
to transmit or receive signals. Antenna selection is done mechanically 
in the control top.
VOCON Board 
OverviewThe VOCON board contains the radio’s microcontrol unit with its 
memory and support circuits, voltage regulators, audio, DSP, ADSIC, 
and power control circuits. Connected to the VOCON board are the 
display board, transceiver board, and control top.
The microcontrol unit (MCU) controls receive/transmit frequencies, 
power levels, display, and other radio functions, using either direct 
logic control or serial communications paths to the devices.The 
microcontrol unit executes a stored program located in the FLASH 
ROM. Data is transferred to and from memory by the microcontrol 
unit data bus. The memory location from which data is read, or to 
which data is written, is selected by the address lines. 
						

							3-4
The SLIC acts as an extension of the microcontrol unit by providing 
logic functions such as lower address latch, reset, memory address 
decoding, and additional control lines for the radio. The microcontrol 
unit controls the crystal-pull circuit to adjust the crystal oscillator’s 
frequency on the microcontrol unit, so that the E-clock’ s harmonics 
do not cause interference with the radio’s receive channel.
Switched +5V is used for all circuits on the VOCON board except the 
audio PA, which is sourced from 7.5V. The regulator automatically 
provides 5V when the radio is turned on. The regulator’s power-down 
mode is controlled by the microcontrol unit, which senses the 
position of the on/off/volume control knob.
The DSP performs all signalling and voice encoding and decoding as 
well as audio filtering and volume control. This includes Private-
Line®/Digital Private Line™ (PL/DPL) encode and alert-tone 
generation. The IC transmits pre-emphasis on analog signals and 
applies a low-pass (splatter) filter to all transmitted signals. It is 
programmed using parallel programming from the microcontrol unit 
and the ADSIC.
The ADSIC performs analog-to-digital and digital-to-analog 
conversions on audio signals. It contains attenuators for volume, 
squelch, deviation, and compensation, and it executes receiver 
filtering and discrimination. The IC requires a 2.4MHz clock to 
function (generated by the ABACUS IC) and is programmed by the 
microcontrol unit SPI bus. 
						

							4-1
Radio Power
4
IntroductionThis section of the manual provides a detailed circuit description of 
the power distribution for an ASTRO Digital SABER radio. 
GeneralIn the ASTRO radio, power is distributed to three boards: 
•transceiver 
•VOCON 
•display 
In the case of a secure model radio, the encryption module is supplied 
also. 
Power for the radio is provided through a battery supplying a nominal 
7.5Vdc directly to the transceiver. The battery is available in the 
following forms: 
•Nickel-Cadmium, High-Capacity (1100mAh), 
Medium-Size Housing
•Nickel-Cadmium, High-Capacity (1100mAh), 
Medium-Size Housing (FM Approved, Submersible)
•Nickel-Cadmium, Ultra-High Capacity (1800mAh), 
Large-Size Housing
•Nickel-Cadmium, Ultra-High Capacity (1800mAh), 
Large-Size Housing (FM Approved)
•Nickel-Cadmium, Ultra-High Capacity (1800mAh), 
Large-Size Housing (FM Approved, Submersible)
•Nickel-Metal-Hydride, Medium-Capacity (950mAh), 
Small-Size Housing
•Nickel-Metal-Hydride, Ultra-High Capacity (1650mAh), 
Medium-Size Housing (FM Approved, Submersible)
B+ from the battery is electrically switched to most of the radio, rather 
than routed through the on/off/volume control knob, S901/R901. The 
electrical switching of B+ supports a “keep-alive” mode. Under 
software control, even when the on/off/volume control knob has been 
turned to the “off” position, power remains on until the MCU 
completes its power-down, at which time the radio is physically 
powered-down. 
						

							4-2
B+ Routing for 
VHF/UHF 
Transceiver BoardsRefer to Figure 1 and your specific schematic diagram.
Raw B+ (7.5V) from the battery (Batt B+) enters the radio on the 
transceiver board through a 3-contact spring pin arrangement (J3) as 
B+, where it is routed through two ferrite beads on the VHF (E1, E101) 
and three ferrite beads on the UHF (E1, E101, E106) to the RF power 
amplifier module (U105) and ALC IC (U101, pin 13). Battery B+ is 
fused, and then routed through the connector J1, pins 19 and 20 to the 
VOCON board (J401, pins 19 and 20). The B+ supply is routed through 
the VOCON board to the on/off/volume control knob (S901/R901) on 
the control top/PTT flex at jack J901, pin 1. With the mechanical on/
off switch (S901) placed in the “on” position, switched B+ (B+ SENSE) 
is routed from the control top flex at connector plug P901, pin 10 and 
applied to the VOCON board at connector jack J901, pin 10. This 
signal is also fed to a resistive divider R222, R223 on the VOCON board 
so that the microcontrol unit (U204) can monitor the battery voltage. 
The switched B+ voltage supplies power to circuits on the transceiver 
board. The 5-volt regulator (U202), is applied this voltage through 
decoupling component C125 to produce a stable 5.0 volt output. Raw 
B+ (7.5V), which is connected to the ALC IC (U101), is switched 
through the output (CATH1) to another 5-volt regulator (U106).
Regulator U202 supplies those circuits which need to remain on at all 
times, such as the reference oscillator (U203), fractional-N-synthesizer 
(U204), D/A IC (U102), and the ABACUS IC (U401). The D/A IC 
controls dc switching of the transceiver board. The SC1 signal at U102 
pin 12 controls transistors Q107, Q111, and the transmit 5 volts (T5).  Figure 1  . B+ Routing for VHF/UHF Transceiver Boards
Battery
7.5V +
RF PA Module
U105
5V Regulator
U202 VCOB IC
U201 ALC  U101T5 L105
CR108
RX
L122
L121 Vcc
RF Amp
U1
Mixer
U2
Q107
R5
5V Regulator
U106 SB+
VHF/UHF Transceiver Board
MAEPF-24700-O
CR109
5V
S
Out
Fuse To/From VOCON Board
SW B+
UNSW B+Raw B+
T5
RX/TX
Ref Osc
U203ABACUS
U401D/A IC
U102 Synth
U204IF Amp
Q601 
						

							4-3
The SC3 signal at U102 pin 14 controls the Rx 5V switch U106, and 
the receive 5 volts (R5). A voltage on the synthesizer SOUT line at 
U204 pin 19 supplies power (Vcc) to the VCO buffer at U201 pin 3.
During the receive mode, regulator U106 supplies regulated 5V (R5) to 
the receiver front end. In the battery-saver mode, R5 can be switched 
on and off by controlling pin 3 of U106. Module U106 is not used 
during the transmit mode. During the transmit mode, transmit 5 volts 
(T5) for the ALC IC and other TX circuitry is obtained from U202 via 
switching transistor Q111.
B+ Routing for 
800MHz 
Transceiver BoardsRefer to Figure 2 and your specific schematic diagram.
Raw B+ (7.5V) from the battery (Batt B+) enters the radio on the 
transceiver board through a 3-contact spring pin arrangement (J3) as 
B+, where it is routed through four ferrite beads (E1, E2, E3, E4) and 
applied to the RF power amplifier (U502) and the ALC IC (U504 pin 
13). Battery B+ is fused and then routed to the VOCON board, where 
it enters on connector J1 pins 19 and 20. On secure radios, Raw B+ is 
also routed to the encryption board so that it can perform key 
management and other functions independently of SW B+.
The SW B+ is applied to the 5V regulator (U505) to produce a stable 
5.0 volt output. Regulator U505 supplies those circuits which need to 
remain on at all times, such as the reference oscillator (U304), 
fractional-n-synthesizer (U302), D/A IC (U503), and the ABACUS IC 
(U401). The D/A IC controls dc switching of the transceiver board. The 
SCI signal at U503 pin 12 controls Q503 and transmit 5 volts (T5). The 
SC3 signal at U503 pin 14 controls the RX 5V switch in Q503 and the  Figure 2 . B+ Routing for 800MHz Transceiver Boards
Ref Osc
U304ABACUS
U401D/A IC
U503 Synth
U302
VCOB IC
U303VCO
U307
5V Regulator
U505 RF PA
Module
U502
RF Amp
U202Mixer
U205Q503ALC
U504
Rx800MHz Transceiver Board
5V SW B+ Raw B+
UNSW B+
IF Amp
Q601
MAEPF-24336-O
CR104
L101
CR102Fuse
Battery
7.5V
+
To/From VOCON Board 
						

							4-4
receive 5 volts (R5). During the receive mode, switch Q503 supplies 
regulated 5volts (R5) to the receiver front end. 
B+ Routing for 
VOCON Boards and 
Display ModulesRefer to Figure 3 and your specific schematic diagram.
Power for the radio is derived from a 7.5 volt battery, which is applied 
to the transceiver board through J3. This Raw B+, or unswitched B+ 
(UNSW B+), is routed to J1 on the transceiver board and then on to 
J401 on the VOCON board. Here the UNSW B+ is forwarded to the 
radio’s control top on/off/volume knob through J901 and a flex 
circuit. The on/off/volume knob controls B+_SENSE to Q206, which in 
turn controls Q207. Transistor Q207 is a solid-state power switch, 
which provides SW B+ to the VOCON board’s analog and transceiver 
5V regulators, the audio PA, the display module, and back to the 
transceiver board. In addition, UNSW B+ is routed to the main digital 
5V regulator (U409); B+ SENSE provides for enabling or disabling this 
regulator. 
In the case of a secure radio model, SW B+ and UNSW B+ are also 
supplied to the encryption module through J801.
Q207 is also under the control of the microcontrol unit (MCU - U204]) 
through a port on the SLIC IC (U206). This allows the MCU to follow 
an orderly power-down sequence when it senses the SW B+ is off. This 
sense is provided through the resistor network of R222 and R223, 
which provides an input to the A/D port on the MCU.
The VOCON board contains two 5V regulators partitioned between 
the digital logic circuitry and the analog circuitry. The 5V regulator for 
the digital circuitry is comprised of U409, CR403, L402, C470, and 
associated components. This circuit is a switched mode regulator. 
Switched mode regulators use a switched storage device (L402) to 
supply just enough energy to the output to maintain regulation. This 
allows for much greater efficiency and lower power dissipation.
The analog circuitry of the ADSIC (U406) and the audio PA (U401) is 
powered through a separate 5V linear regulator (U410).
It should also be noted that a system reset is provided by U407. This 
device brings the system out of reset on power-up. It provides a system 
reset to the microcomputer on power-down or if the digital 5V 
regulator falls out of regulation. 
						

							4-5
Figure 3 .  B+ Routing for Vocoder/Controller (VOCON) Boards
5V Regulator
U410 ADSIC
U406 DSP56001
U405
256Kx8
FLASH
U404 8Kx24
SRAM
U402
Audio
PA
U401
SRAM
U202
EEPROM
U201
SLIC IV
U206Switch
Q207
On
Off
Controls
Flex
SW_B+
5V Analog
5V Digital
B+_CNTLB+_Sense
Vocoder/Controller
UNSW_B+ SW_B+
J401 J201 Universal ConnectorOpt_B+
Display Module
8Kx24
SRAM
U403
8Kx24
SRAM
U414
256Kx8
FLASH
U205
256Kx8
FLASH
U210
5V Regulator
U409
MAEPF-24335-O
HC11F1
MCU
U204