SERVVICE MMANUAAL VECTORR VT- 443 R-2 

CIRCUIT DESCRIPTION

RECEIVER The signal from the antenna is passed through a transmission/reception selector circuit and is amplified by T215. The signal after amplified enter to 1845 for processing then output the audio, the audio signal is amplified by LM4871 and output by the speaker at last.

TRANSMITTER

The signal from the microphone passes through 1845 ,after modulation in the carrier modulation, the modulation signal with the carrier promotes by buffer T151,T141,and amplified by T131 then sends to the antenna terminals.

TRANSMISSION/RECEPTION SELECTOR CIRCUIT

The transmission output is passed through the transmission/reception selector circuit and low-pass filter to the antenna. The transmission/reception selector circuit, which consists of diodes D121, D122 D211 and D212 , is turned on during transmission and off during reception to switch the signal.

CONTROL CIRCUIT The control circuit consists of a microprocessor (U511) and its peripheral circuits. U511 mainly functions as follow: 1) Switching between transmission and reception by the PTT signal input.

2) Reading system, group, frequency, and program data from the memory circuit.

1. Reset and backup circuits

When the SB is turned on, a high level pulse is output from the reset circuit consisting of T535,

C537, and R537 to reset microprocessor. If the SB is turned off, the voltage detection MCU

detects a 5 V drop, and outputs a low signal, it outputs data to U821(24C32) and enters backup

mode.

2.Memory Circuit

Memory circuit consists of the MCU(U511) and an EEPROM (U821). An EEPROM has a capacity of

32k bits that contains the transceiver control program for the MCU and data such as transceiver

channels and operating features.

3. Battery save circuit

The squelch is off during receive. The power circuit enters battery save mode if no key has been

pressed for five seconds.

This circuit is controlled by microprocessor directly.

4. Low Battery Warning

The battery voltage is checked using by the microprocessor. The transceiver generates a warning

tone when it falls below the warning voltage.

5. Keys and rotary encoder circuit

The signal from keys and rotary encoder input to microprocessor directly.

6.LCD control circuit The LCD control circuit is turned on or off by directly flowing current to the microprocessor ports.

1845 DESCRIPTION

MAINLY SECTION DESCRIPTION

1.DSP consists of IF amplifier, FM modulation, RSSI calculator, AFC control circuit,

audio/audio mixer filter, CTCSS/DCS filter and so on.

2.Synthesizer mainly functions

The synthesizer produces a local oscillator signal, used to switch the RF input to a

continuous low medium frequency.

Synthesizer provides the base clock to adjust the VCO frequency.

3.BASE CLOCK

1848 ports more base clocks, for example, 12.8 MHz,13MHz and so on.

4.SERIAL CONTROL INTERFACE

A three lines serial control interface is used to read the main IC and 1845 control

record. Serial control is 24 characters in length, 18 bit numeric string and 6 bit

address string.

Programming software main functions

1 English Chinese programming software

2 Receiving frequency and transmitting frequency

3 Receiving tone and Transmitting tone

4 Time Out Timer

5 Squelch level(1 9) selectable

6 Power save

7 frequency step

8 Store channels

9 VOX sensitivity

10 SCAN TYPE TO/CO/SE

R-201-02

R-201-02

R-201-02

R-201-02

1 2 3 4 5 6

654321

E

D

C

B

A

C557104P

R557

10KR556150K

R555150K

C541103P

D551GREEN

BATTI

BATTI

3V

3VBATTI

R561470R

R5671K

C567102P

D561LED

D562LED

T567DTC114EE

D552RED

R551560R

R552560R

T551DTC114EE

T552DTC114EE

CO

M1

1C

OM

22

CO

M3

3C

OM

44

SE

G0

5S

EG

16

SE

G2

7S

EG

38

SE

G4

9S

EG

510

SE

G6

11S

EG

712

SE

G8

13S

EG

914

SE

G10

15S

EG

1116

SE

G12

17S

EG

1318

SE

G14

19S

EG

1520

SE

G16

21S

EG

1722

SE

G18

23S

EG

1924

SE

G20

25S

EG

2126

SE

G22

27S

EG

2328

SE

G24

29S

EG

2530

SE

G26

31S

EG

2732

SE

G28

33S

EG

2934

SE

G30

35S

EG

3136

LCD

CS1

RD2

WR

3D

ATA

4V

SS

5O

SC

O6

OS

CI

7V

LCD

8V

DD

9IR

Q10

BZ

11B

Z12

COM0 13COM1 14COM2 15COM3 16S31 17S30 18S29 19S28 20S27 21S26 22S25 23S24 24S23

25S

2226

S21

27S

2028

S19

29S

1830

S17

31S

1632

S15

33S

1434

S13

35S

1236

S1137S1038S939S840S741S642

S444S345S246S147S048

S543U525

HT1621

R526100R

R527NC

R327

4K7

C324104PC323

10uF/16V

R3253K9

R326

3K9

C326104P

C325104P

NC1CTS_IN2SQ/GPO33AVDD4IN15IN26AVSS7XTAL28XTAL19NC10

NC

11A

VD

D12

AFO

UT

13A

VD

D14

AV

DD

15A

VS

S16

AV

SS

17V

OX

/GP

O2

34P

DN

35IN

T/G

PO

136

SE

N37

SC

LK38

SD

IO39

NC

40

U251RDA18

C14718P

L1421R0

L143101T

C

47C141NC

R14NC

R14547K

C14470

C145470P

3T

C162470P

C163104P

C24312P

C24115P

C236102P

C235104P

C254103P

C251104P

R251NC

R25222K

R25310K

C253104P

C252103P

C264683P

C271104P

R2711K

GND 1LNAN 2RF GND 3LNAP 4GND 5XTAL 6

RS

T7

SE

N8

SC

LK9

SD

IO10

RC

LK11

VIO

12

AVDD13GND14ROUT15L OUT16GND17DVDD18

GP

IO3

19G

PIO

220

GP

IO1

21N

C22

NC

23G

ND

24

U331RDA5802E

R323NC

R324NC

R54210K

R54110K

R545100R

A0 1A1 2

GND 4DA5 CK6 A2 3WP7 Vcc8

U54124C32

R544100R

C526104P

C52710uF/16V

L526

101T

CHG_DETTXD

AFOP-AMP

KEY_IN1

P-FM

KEY_IN3

LCD_DATALCD_WRLCD_CS

FM_D

ATA

FM_C

LK

RDA1845_PDNRDA1845_ENRDA1845_CLKRDA1845_SDA

CTC/CDS _DETVOX_DET

TX_RF

3VBATTI

T2782SK1824

R279470P

R2781K

R570100K

C570104P

C161104P

R16110K

R16210K

T1612SA1362

C512470P

C513NC

C52222P

C52122P

L5120R

C511104P

L5110R

CR5214.0MHz

3V 3VKE

Y_O

UT2

KE

Y_I

N2

KE

Y_I

N1

KE

Y_O

UT1

KE

Y_I

N3

LCD_CSLCD_WRLCD_DATA

BA

CK

LIG

HT

RLEDGLED

CTC/CDS OUTSQ

AF_MUTE

Out 1

VDD 2NC3

GND4

U531NC C532

104PD531NC

R5320R

R53147K

C531NC

PTT

/RX

D

CH

G_D

ET

PTT/RXD

R57210K

R57310K

R57410K

C32

P-A

MP

P-F

M

RESET

J2RESET

J4TXD

R512

10K

R513

10K

J5VDD

J6GND

J7PTT/RXD

CTC/CDS _DET

R562470R

T1512SC3356

L15118nH

R15222R

L148

0R

C14918P

C152103P

C151470P

C15533P

R151NC

R153

22K

C144NC

R14447R

T1412SK3078

3T

R146120K

C148NC

R53747K

T535

KTC4082(HF)

T546NC

BATTO

R546NC

R547NC

R548NC

C5460R

C273NC

C272103P

C537103P

R5111K

J3RXD

P-RX P-RX

RT22222K C222

20P

RV22150K

R22247K

SEG24 1SEG23/R77 2SEG22/R76 3SEG21/R75 4SEG20/R74 5SEG19/R73 6SEG18/R72 7SEG17/R71 8SEG16/R70 9SEG15/R67 10

SEG12/R64 13SEG13/R65 12SEG14/R66 11

SEG11/R63 14SEG10/R62 15SEG09/R61 16

SE

G08

/R60

17S

EG

07/R

5718

SE

G06

/R56

19S

EG

05/R

5520

SE

G04

/R54

21S

EG

03/R

5322

SE

G02

/R52

23S

EG

01/R

5124

SE

G00

/R50

25R

00/P

EM

0/T0

O26

R04

/BU

ZO27

R05

/INT0

/EC

128

R06

/INT1

29R

07/IN

T230

R10

/PW

M1/

T2O

31R

11/A

CK

/SC

K32

R1233R1334R1435R1536R16/SDA37R17/SCL38R20/AN039R21/AN140R22/AN241R23/AN342R24/AN443AVREF44R4245PLLC46VDD47R4348

R44

49V

SS

50R4

5/X

IN51

R46

/XO

UT

52R

47/R

ES

ETB

53C

OM

054

CO

M1

55C

OM

256

CO

M3

57S

EG

39/C

OM

458

SE

G38

/CO

M5

59S

EG

37/C

OM

660

SE

G36

/CO

M7

61S

EG

2762

SE

G26

63S

EG

2564

U511MC81F8616L

C501NC

XI

XO

RE

SE

T

GND_D

VD

D

ROM_SDAROM_SCKBATT TESTKEY_OUT1KEY_OUT2P-RXKEY_IN1KEY_IN2KEY_IN3PTT/RXDTXD

3V

AP

C

CT

C/C

DS

_DE

T

P-AMPC

TC/C

DS

OU

TB

AC

KLI

GH

TV

OX

_DE

T

AF_MUTEFM_DATAFM_CLK

DTM

F

DT

MF

BE

EP

R569100K

C569

104P

LCD

_CS

LCD

_WR

LCD

_DA

TA

RLE

DG

LED

P-A

MP

VT

X_C

TR P-FM

P-F

MS

Q

CHG_DETRDA1845_SDARDA1845_CLKRDA1845_ENRDA1845_PDN

BEEPB

EE

PBACKLIGHT

MENUVFO

MR ENT

D566LED

R566100R

XOUT 3

VC15C4

GND 2

CR222

13MHz

C322104P

C320102P

R322150R

AP

C

APC

R2911K

C291104P

R29215K

C292224P

C293224P

R25410K

R164NC

R163NC

T165NC

C165NC

7 8 9 10 11 12

121110987

C124102P

C21210P

L121220nH

R123120R

C122470P

C1216P8

L21104/12/4T

C118470P

C1174P

L116

04/15/4T

L114

04/15/4T

L112

04/15/4TCC115

6PC1133P5

C1141P5

C1122P4

C1161P

C2112P

C262104P

R263

1K8

R262

470R

SW586PTT

R5861K

C586102P

D212HSC277

D122HVC131

C2634.7uF/16V

BATTI

MIC

AFO

P-A

MP

3V

3V

L921

68T

SW587MONI

R587

1KC587102P

SW588CALL

R588

1KC588102P

R5921K

TXD

AFO

P-A

MP

D121HVC131

D211HSC277

C92110uF/16V

BATTO

1

2

3

4

JP921JP4

C2150R

C213NC

L212NC

L21304/12/4T

C312103P

C311470P

L317100nH

C31547P

T3152SC4226

R314

100K

R312330R

L313100nH

C314103P

C31852P

NC1CTS_IN2SQ/GPO33AVDD4IN15IN26AVSS7XTAL28XTAL19NC10

NC

11A

VD

D12

AFO

UT

13A

VD

D14

AV

DD

15A

VS

S16

AV

SS

17A

VD

D18

NC

19N

C20

NC 21NC 22RFIN 23NC 24AVDD 25RFOUT 26NC 27AVDD 28PABIAS 29NC 30

NC

31A

VS

S32

CTS

_OU

T33

VO

X/G

PO

234

PD

N35

INT/

GP

O1

36S

EN

37S

CLK

38S

DIO

39N

C40

U251RDA1845

L1421R0

L143101T

L141

2.2nH

C140

470PC141NC

C13939P

T131RFM03U3CT

C13030P

C12930P

C12812P

R137100RR142

NCC142470P

C137470P L129

04/15/8T

L132101T

C131104P

C132103P

C133470P

C134470P

C143470P

C1351uF

3T

SD1Bypass2+in3- in4 Vo1 5VDD 6Vss 7Vo2 8

U351LM4871

R355

100KR356

2K2

C353105P C351

10uF/16VC352103P

C356

105P

E93110uF/16V

C932103P

E93210uF/16V

Out5Gnd 2

Vin 1

CE 3NC4

U931RP103N331D-TR-F

5P

C264683P

C271104P

R237

4R7

R264

560R

C23110uF/16V

C232100P

C238100P

C237104P

C234100P

C233104P

L231101T

GND 1LNAN 2RF GND 3LNAP 4GND 5XTAL 6

RS

T7

SE

N8

SC

LK9

SD

ION

CN

C23

GN

D24

E

T311DTA114YE

P-F

M

P-FM

P-A

MP

J1BATT

RX

D

CR33132.768KHz

CHG_DETTXD

AFOP-AMP

KEY_IN1

P-FM

KEY_IN3

PTT/RXD

R35410K

C21427P

C922102P

C230104P

C12012P

T918DTC114EE

R91810K

R9194K7

178

R138

47KC138470P

3T 3T

R139100K

L21747nH

L31647nHC316

68P

C31752P

C31310P

L13727nH

C136103P

C1574P

C1585P

C923103P

C47

TXD

RX

D

TXDRXD

MIC

BATTI

BATTI3V

L130HL04/12/2T

T351DTC114EE

D931NC

C216103P

T2152SC4226

R215100K

R216330R

C21715P

T216DTA114YE

P-RX

C265683P

C9N

KEY_IN3KEY_IN1

CH

G_D

ET

MIC

R1040.39R1050.39R1060.39

R170150K

R171150K

R172150K

R173150K

R174150KR175

150K

R17710K

R181220K

R18247K

R1831M

R184

330R

R185120K

R186

10K

C173470P

C172NC

C174103P

C175100P

C180470P

C181103P

C187104P

C183102P

2

31

84

U170ALM2904V

76

5

U170BLM2904V

T171DTC114EE

T181DTA114YE

R188

10KC186470P

T1822SK1824

BATTI BATTI

BATTI

BA

TTI

AFO

APC

AP

CA

PC

3T

3T

BATTI3V

3V

R187

10K

C218NC

C219470P

C1644.7uF/16V

10 11 12 13 14 15

A

B

C

D

E

151413121110

SW921ARD810S

32

5

4

1

67

JK351ST-303

L121220nH

R123120R

C1216P8

L21104/12/4T

C118470P

C1174P

L116

04/15/4T

L114

04/15/4T

L112

04/15/4TL1111uHC111

NCC115

6PC1133P5

C1141P5

C1122P4

C1161P

ANT111ANT-2

C2112P

SW586PTT

R5861K

C586102P

D212HSC277

D122HVC131

SP351SP

AFO

P-A

MP

MIC261MIC

L921

68T

SW587MONI

R587

1KC587102P

SW588CALL

R588

1KC588102P

R35710R

C357470P

R5921K

TXD

AFO

P-A

MP

D121HVC131

D211HSC277

12

JK911DC00960-B

C92110uF/16V

BATTO

1

2

3

4

JP921JP4

SD1Bypass2+in3- in4 Vo1 5VDD 6Vss 7Vo2 8

U351LM4871

R355

100KR356

2K2

C353105P C351

10uF/16VC352103P

C356

105P

E93110uF/16V

C932103P

E93210uF/16V

Out5Gnd 2

Vin 1

CE 3NC4

U931RP103N331D-TR-F

20100505

VT- 43 R-2SCHEMATIC DIAGRAM

P-A

MP

J1BATT

RX

D

R35410K

C922102P

T918DTC114EE

R91810K

R9194K7

C923103P

C924470P

TXD

RX

D

TXDRXD

MIC

BATTI

BATTI3V

C2613K3

T351DTC114EE

D931NC

C911NC

KEY_IN3KEY_IN1

CH

G_D

ET

MIC

R1040.39R1050.39R1060.39

R170150K

R171150K

R172150K

R173150K

R174150KR175

150K

R17710K

R181220K

R18247K

83M

R185120K

R186

10K

C173470P

C172NC

C174103P

C175100P

C180470P

C181103P

C183102P

2

31

84

U170ALM2904V

6

5

170B904V

T171DTC114EE

860P

BATTI BATTI

BATTI

BA

TTI

AFO

3T

3T

BATTI3V

3V

R-201-02