TMC Radio SRP 9100, Руководство по обслуживанию

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Page 4.8
3 ~ TECHNICAL DESCRIPTION
Analogue voltages to be monitored such as PLL Loop Voltage (LOOP_VOLTS), key detect (KEY_DET), battery
voltage (BAT_SENSE), transmitter current (TC_CURRENT), volume level (VOLUME) and external sense
(EXT_SENSE) are connected to the inverting inputs. The analogue voltages are compared with the ramp
voltage as they increase and the comparator switches at the point where the input voltage exceeds the ramp.
The PLA compares the time that this occurs with the PWM signal and converts it to a binary value.
4.5 M
EMORY
Memory consists of the internal DSP memory and an external 8MB non-volatile Flash Memory U202. When
power is off, all program SW and data are retained in Flash Memory. At power-on, a boot program downloads
the DSP and PLA SW from Flash Memory to their internal RAM’s for faster program execution and access to
data. PLA SW is loaded by the factory into the Flash Memory and can be updated via the Alignment Tool. DSP
SW comprises Start-up code that is also loaded by the factory. High-level SW comprising Operational Code
and Customer Configuration are loaded at distribution centres and are loaded via the FPP Programmer.
DSP
U201
Synthesiser
U701
PLA
U300
Reset
U200
Clock
X200
Flash
Memory
U202
CODEC
U800
Serial port
Serial port
TX_DATA
RX_DATA
XTAL_SHIFT
AGC
TX_Power
1. BACKLIGHT
2. SPKR_ON
3. PA_ON
4. TX_MODE
5. LEDS
6. PWR_OFF
7. CHG_INH
8. SYNTH_FAST
9. ANALOG GATE CONTROLS
Tune 1 - 4
BAT_SENSE
Rx
Audio
Tx
Audio
AFC
FUNCTION_EN
LOOP_VOLTS
EXT_SENSE
1. PWR_ON
2. PTT
3. PWR_SENSE
Bit
Outputs
TX_CURRENT
VOLUME
POWER_SENSE
MOD BAL
Bit
Inputs
LOCK
PWM
Outputs
Sampled Analog Inputs
KEY_DET
BAT_SENSE
Figure 4-4 Controller Block Diagram
4.6 P
OWER
S
UPPLIES
4.6.1
Power On Function
The unregulated battery input (6.4V ~ 9.6V DC) is routed directly to all high current devices after the battery
fuse and is then switched via FET Q900 to provide BAT_SW supply for all other circuits. The output from Q900
feeds three low dropout series regulators, switched battery voltage and a switch-mode 3.3V DC supply. These
regulated supplies power auxiliary supplies as well as the negative voltage generator. The radio ON/OFF
function is achieved through Q908 and Q909. The On-Off switch is connected between unswitched fused
battery and PWR_ON. When the switch is turned on, a DC pulse is applied to Q908 that turns on the main
FET switch Q900 for approximately 1 sec. In this time, the radio DSP samples the PWR_SENSE line and
determines the state of the on-off switch. If the on-off switch is on, the DSP raises the PWR_OFF line and
latches the main FET on, which then maintains power to the radio circuitry.