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Theory of Operation

11

MT-3 FM Transmitter Mainboard Instruction Manual 

IM20-MT3TXMN

time-out-timer Circuitry

The MT-3 FM Transmitter also has an 

associated programmable push-to-talk 

(PTT) time-out-timer (TOT) circuitry on the 

transmitter mainboard. The TOT circuitry 

is powered via J34 from the continuous 

+9.5 VDC supply and is programmable for 

various time-out periods.

The TOT input trigger (enabled by J33) is 

normally high and in this state the timer is 

disabled. When the input trigger level falls 

below +2.0 VDC, the timer is activated, the 

TOT output trigger (enabled by J35) is pulled 

low and the transmitter is keyed. If the input 

trigger rises above +2.4 VDC or if the time-

out period is exceeded, the output trigger will 

go high, disabling the transmitter. If the time-

out period is exceeded, the TOT input trigger 

must go high and then low again in order to 

re-key the transmitter.

The time-out duration is jumper selectable 

from 1 second to 8 hours (see Table 1). 

The positions of the jumpers are on the 

top (through-hole component) side of the 

transmitter mainboard.

 

J32  J31  J29  J28    J26  J27 

Minutes

  I 

0.01

  I 

n/I 

0.01

  I 

n/I 

0.01

  I 

n/I 

0.01

  I 

n/I 

n/I 

0.02

  I 

n/I 

0.02

  I 

n/I 

n/I 

0.03

  I 

n/I 

n/I 

0.04

  I 

n/I 

n/I 

0.05

  I 

n/I 

n/I 

0.06

  I 

n/I 

n/I 

n/I 

0.08

  I 

n/I 

0.10

  I 

n/I 

n/I 

n/I 

0.12

  I 

n/I 

n/I 

0.15

  I 

n/I 

n/I 

0.19

  I 

n/I 

n/I 

0.23

  I 

n/I 

n/I 

n/I 

0.31

  I 

n/I 

n/I 

0.38

  I 

n/I 

n/I 

n/I 

0.47

  I 

n/I 

n/I 

n/I 

0.62

  I 

n/I 

n/I 

n/I 

0.75

  I 

n/I 

n/I 

n/I 

0.94

  I 

n/I 

n/I 

n/I 

n/I 

1.25

 n/I 

1.5

  I 

n/I 

n/I 

n/I 

n/I 

1.88

 n/I 

n/I 

2.5

 n/I 

n/I 

3.0

 n/I 

n/I 

3.75

 

N/I 

N/I 

N/I 

5.0

 n/I 

n/I 

6.0

 n/I 

n/I 

n/I 

7.5

 n/I 

n/I 

n/I 

10

 n/I 

n/I 

n/I 

12

 n/I 

n/I 

n/I 

15

 n/I 

n/I 

n/I 

n/I 

20

 n/I 

n/I 

24

 n/I 

n/I 

n/I 

n/I 

30

 n/I 

n/I 

n/I 

40

 n/I 

n/I 

n/I 

48

 n/I 

n/I 

n/I 

60

 n/I 

n/I 

n/I 

n/I 

80

 n/I 

n/I 

n/I 

96

 n/I 

n/I 

n/I 

n/I 

120

 n/I 

n/I 

n/I 

n/I 

160

 n/I 

n/I 

n/I 

n/I 

192

 n/I 

n/I 

n/I 

n/I 

240

 n/I 

n/I 

n/I 

n/I 

n/I 

320

 n/I 

n/I 

n/I 

n/I 

n/I 

480

N/I = Not Installed

I = Installed

Bold

 text represents default settings.

TABLE 1: Time-out Jumper Settings and Duration

Содержание MT-3 Series

Страница 1: ...means electronic mechanical photocopying recording or otherwise without the prior written consent of Daniels Electronics Ltd The stylized Daniels Electronics Ltd and DE logo are registered Canadian a...

Страница 2: ...identify the significance of a revision Each element of the revision number signifies the scope of change as described in the diagram below DOCUMENT REVISION DEFINITION Major Revisions The result of...

Страница 3: ...ard Interconnection Pin Definitions 26 FM Audio Processor Alignment 27 Troubleshooting 31 Temperature Compensation 32 FM Audio Processor Jumper Configurations 32 Illustrations and Schematics 35 MT 3 F...

Страница 4: ...iv MT 3 FM Transmitter Mainboard Instruction Manual IM20 MT3TXMN This Page Intentionally Left Blank...

Страница 5: ...the amplifier and the synthesizer modules are frequency band sensitive plug in modules Circuitry and jumpers on the transmitter mainboard control the operation of the modules as well as the overall o...

Страница 6: ...2 MT 3 FM Transmitter Mainboard Instruction Manual IM20 MT3TXMN This Page Intentionally Left Blank...

Страница 7: ...Emissions Conducted Spurious 90 dBc 80 dBc VSWR Protection 20 1 VSWR at all phase angles Operating Temperature Range 30 C to 60 C Operating Humidity 95 RH non condensing at 25 C Operating Voltage 13...

Страница 8: ...s standard MT 3 Repeater Subrack Subracks modules comply with IEEE 1101 DIN 41494 and IEC 297 3 mechanical size modular arrangement External Connections RF Connection Type N connector located on the m...

Страница 9: ...en SW1 is in the OFF position the transmitter is turned off however 13 8 VDC is still present on the transmitter mainboard as the 13 8 VDC supply is not switched When SW1 is in the KEYED position 9 5...

Страница 10: ...of U2a goes low which triggers the transmitter s TOT located on the FM Audio Processor The TOT s output is AND ed with the MIC PTT NTO signal U2c and the PTT NTO signal U2d When any one of the preced...

Страница 11: ...for the synthesizer module PTT input Q4 Turns on Q5 which turns on the 9 5 VDC Switched supply Q6 Turns on Q7 which turns on the 9 5 VDC PTT Switched supply The 9 5 VDC Switched supply Q5 can also be...

Страница 12: ...and balanced audio compression amplifiers will be disabled eliminating the use of the front panel microphone jack for local microphone operations With this configuration the balanced audio is routed a...

Страница 13: ...B18 and Z18 by a transformer T1 Two audio outputs from the FM Audio Processor are routed to the synthesizer modules Microphone Audio Normally the microphone audio is sent from the attached transmitter...

Страница 14: ...orward and reverse power sense lines to the backplane connector pins B26 and Z26 respectively The forward and reverse power sense lines from the amplifier can be open collector or linear outputs depen...

Страница 15: ...t side of the transmitter mainboard J32 J31 J29 J28 J26 J27 Minutes I I I I I I 0 01 I I I I I N I 0 01 I I I I N I I 0 01 I I I N I I I 0 01 I I I N I I N I 0 02 I I N I I I I 0 02 I I I N I N I I 0...

Страница 16: ...s in transmitter deviation over temperature caused by changing characteristics of synthesizers and oscillators A single chip 10th Order Linear Phase Low Pass Splatter Filter for increased cut off atte...

Страница 17: ...ch 2 Regular Modulation Buffer Subtone 1 3 KHz Direct Modulation Offset Buffer TCVCXO Modulation Buffer Offset TCVCXO DC Level Adjust Reg Mod Out Low Freq Out Inverting Amp Coupling Select 2 Port Pola...

Страница 18: ...z tone at 18 dBm gives 500 Hz All Other Audio Inputs Disabled Interconnection Pin Layout Diagram PCB 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 P1 P2 P4 P3 Balanced Input END VIEW Mic Input Subtone Inp ut 1 8V 9...

Страница 19: ...low frequency modulation capabilities of the synthesizer module The DIRECT MODULATION inputs on the J1 control connector of the MT 3 Motherboard will be used B20 for TX A and A20 for TX B Turn on Tim...

Страница 20: ...nse jumper JU1 at Y and X position respectively FM Audio Processor Balanced Input The 600 balanced input uses the ALC pre amplifier U1B with input level control pot R31 The balanced input level contro...

Страница 21: ...ion Output port while Subtone 2 is used for DCS Both subtone inputs have an input level control In order to maintain a uniform frequency response from 50 Hz to 300 Hz dual port modulation techniques a...

Страница 22: ...CROPHONE COMPRESSION CONTROL X Y X Y X Y FLAT AUDIO PRE EMPHASIS X Y TWO PORT POLARITY SUBTONE 1 INPUT CONTROL LEVEL 3 P1 2 P1 1 P1 4 P1 3 P3 3 P2 1 P2 4 P2 9 5V CONTINUOUS C10 10nF 4K53 R46 C5 10nF 1...

Страница 23: ...el temperature compensation for synthesizer sensitivity variations Due to the many different characteristics of various synthesizers many components are selected for best performance over the temperat...

Страница 24: ...D FOR DIGITAL MOD AUXILIARY INPUT LEVEL CONTROL X Y MICROPHONE AGC PREAMP BALANCED AGC PREAMP hi gh w i deband sel ect l ow nar r ow band sel ect X Y BALANCED COMPRESSION CONTROL FLAT AUDIO PRE EMPHAS...

Страница 25: ...rrying half the audio level as determined by resistive divider comprised of R22 and R21 X Y DEVIATION CONTROL LOW FREQUENCY DIRECT MODULATION OUTPUT X Y X Y X Y 10 POLE LOWPASS FI LTER X Y X Y VOICE S...

Страница 26: ...22 MT 3 FM Transmitter Mainboard Instruction Manual IM20 MT3TXMN This Page Intentionally Left Blank...

Страница 27: ...sing an ordinary soldering iron Removal and replacement of surface mount components should be performed only with specifically designed surface mount rework and repair stations complete with Electrost...

Страница 28: ...ppm frequency tolerance General Information Before proceeding with the transmitter alignment check that the appropriate jumpers are installed See Standard Factory Settings and Jumper Configuration sec...

Страница 29: ...talled Amplifier power sense output configuration J13 X Amplifier power sense output configuration J14 X Amplifier power sense output configuration J15 X Amplifier power sense output configuration J16...

Страница 30: ...o the MT 3 Motherboard Pin Name Pin Name Pin Name D2 No Connect B2 13 8 VDC Z2 13 8 VDC D4 No Connect B4 MIC Out Z4 MIC In D6 No Connect B6 9 5 VDC Z6 9 5 VDC D8 No Connect B8 Relay Positive Z8 Relay...

Страница 31: ...tter is most commonly set up for a single frequency operation there are times when an application requires multiple frequencies per transmitter This also changes the standard tuning procedure slightly...

Страница 32: ...AF Gen 1 kHz Tone 18 dBm 5 R42 Subtone1 Adjust and measure 500 Hz Deviation Monitor 6 OST 3H035 2 Port OST 3H045 2 Port Change AF Gen freq AF Gen 40 Hz 18 dBm 7 R36 TCXO Adjust and measure 500 Hz 8 Su...

Страница 33: ...d measure Distortion Analyzer AF Filter 15 kHz 4 0 THD 19 Microphone Input Front Panel Pin 2 Change level AF Gen 1 kHz Tone 10 dBm 20 R2 Microphone Adjust and measure 3 kHz Deviation monitor 21 Microp...

Страница 34: ...3H035 2 Port OST 3H045 2 Port Change AF Gen freq AF Gen 40 Hz 18 dB 7 R36 TCXO Adjust and measure 500 Hz 8 Subtone 1 input Change AF Gen freq AF Gen 300 Hz 18 dBm 9 Deviation Monitor Should measure 50...

Страница 35: ...Test Subtone Measured 1 8 kHz 10 dBm 1 kHz 8 dBm 1 kHz 10 dBm 100 kHz 18 dBm TP3 5 2 V P P 3 8 V P P N A N A TP12 N A N A 3 8 V P P N A TP10 6 5 V P P 4 9 V P P 4 8 V P P 1 1 V P P TP5 2 4 V P P 1 3 V...

Страница 36: ...a constant transmitter audio deviation with a fixed level input signal It is capable of not only compensating for temperature related level variations within the audio processor typically 0 3 to 0 5 d...

Страница 37: ...XY X Audio Gate Switch X X X 22 XY Y Splatter Filter Enable Bypass Y Y Y 23 Single Open Narrow Band Gain Reduction Open Open Open 24 XY Factory Custom Temperature Compensation Network Contact Factory...

Страница 38: ...MT 3 FM Transmitter Mainboard Instruction Manual IM20 MT3TXMN 34 This Page Intentionally Left Blank...

Страница 39: ...ring convention in which the last two digits of the circuit board number represent the circuit board version All PCBs manufactured by Daniels Electronics Ltd are identified by one of the following num...

Страница 40: ...ED J12 R25 27K4 R26 1K0 Q10 PZT2222A J14 J15 J13 FUSE OPTIONAL 9 5 VDC CONTINUOUS J9 SQL DE EMP INPUT MIC OUT MIC IN BALANCED INPUT SIDE 2 600 OHMS BALANCED INPUT SIDE 1 SUBTONE INPUT 1 SUBTONE INPUT...

Страница 41: ...LPF22 B B4 LPF23 B B3 LPF24 B B3 LPF25 B B3 LPF26 B B3 LPF27 B B3 LPF28 B B2 LPF29 B B2 LPF30 B B2 LPF31 B B2 LPF32 B B2 LPF33 B B1 LPF34 B B1 LPF35 B B1 Q1 B E6 Q3 B E5 Q4 B F5 Q5 B F4 Q6 B E5 Q7 B E...

Страница 42: ...PF3 B B7 LPF4 B B7 LPF5 B B7 LPF8 B B6 LPF10 B B6 LPF12 B B6 LPF15 B B5 LPF18 B B4 LPF19 B B4 LPF20 B B4 LPF21 B B4 LPF22 B B4 LPF23 B B3 LPF24 B B3 LPF25 B B3 LPF26 B B3 LPF27 B B3 LPF28 B B2 LPF29 B...

Страница 43: ...1 3 X Y Y X Y X Y X Y UNDER U6 X Y X Y X Y JA5 1 JA5 2 JA5 3 JA5 4 JA2 4 JA3 1 JA4 2 JA3 2 JA4 4 JA1 4 JA3 3 JF2 3 JF2 4 JF1 4 JA3 4 JA2 3 JA4 3 JA4 1 JA2 1 JA2 2 JA1 1 JA1 2 JA1 3 JF1 1 JF1 3 JF2 2 J...

Страница 44: ...E REVISED BY REV DANIELS ELECTRONICS LTD TM VICTORIA BC SW1 PF3 MIC J2 D1 C1 HIGHEST REFERENCE DESIGNATORS UNUSED REFERENCE DESIGNATORS 03 JUL 03 SHANE AEBISCHER 1 2 43 921212 M GAUBE 07 APRIL 92 MT 3...

Страница 45: ...4 1 2 3 C38 3 3nF P2 P3 P4 C37 3 3nF C32 N I P1 P5 P8 P6 P7 C15 3 3nF R19 THD N I C34 1 0 uF R27 THD N I R1 J1 R2 K3 R3 H1 R4 J1 R5 I2 R6 J2 R7 H2 R8 E2 R9 E2 R10 H2 R11 G2 R12 A1 R13 F1 R14 O3 R15 F...

Страница 46: ...TER Y X Y X Y X 10 POLE LOWPASS FILTER Y X Y X OPTIONAL Y X BALANCED AGC PREAMP MICROPHONE AGC PREAMP Y X AUXILIARY INPUT LEVEL CONTROL NOT INSTALLED FOR DIGITAL MOD 9 5V CONTINUOUS Y X Y X Y X Y X LO...

Страница 47: ...5A104K5R C10 CAP 1uF CER 2225 5 50V X7R 1008 6H105J5R C12 CAP 10nF CER 0805 10 50V X7R 1008 4A103K5R C13 CAP 10nF CER 0805 10 50V X7R 1008 4A103K5R C14 CAP 10nF CER 0805 10 50V X7R 1008 4A103K5R C15 C...

Страница 48: ...T PF2 HEADER 1 R A 2 ROW X 2PIN 5010 H202RA9T PF3 HEADER 1 R A 2 ROW X 2PIN 5010 H202RA9T Q1 TRANSISTOR BC817 25 NPN SOT23 2120 BC817025 Q3 TRANSISTOR BC817 25 NPN SOT23 2120 BC817025 Q4 TRANSISTOR BC...

Страница 49: ...K1 0805 1 100ppm 1150 4A6812FP R34 RES SM 27K4 0805 1 100ppm 1150 4A2742FP R35 RES SM 27K4 0805 1 100ppm 1150 4A2742FP R36 RES SM 221K 0805 1 100ppm 1150 5A2213FP R37 RES SM 1K00 0805 1 100ppm 1150 3A...

Страница 50: ...EXAN 14HP VHF ORANGE 3536 10101405 1 LBL LOCKWASHER M3 SPLIT A2 STEEL 5814 3M0LK00S 4 EA NAMEPLATE BLANK 14HP ALUM 3702 10001214 1 EA NUT M2 5 HEX 5 0mm FLATS A2 for CONN1 5813 2M5HX50S 2 EA NUT M2 5...

Страница 51: ...uF C 1206 80 20 25V X7R 1008 6B105Z3R C5 CAP 10nF CER 0805 10 50V X7R 1008 4A103K5R C6 CAP SM 1uF TANT 20 16V 1055 5A105M16 C7 CAP 680nF CER 1206 20 25V X7R 1008 5B684M3R C8 CAP SM 4 7uF TANT 10 16V 1...

Страница 52: ...0 25V X7R 1008 6B105Z3R C47 CAP 1uF C 1206 80 20 25V X7R 1008 6B105Z3R C48 CAP SM 4 7uF TANT 10 16V 1055 5B475K16 C49 CAP 10nF CER 0805 10 50V X7R 1008 4A103K5R C50 CAP SM 4 7uF TANT 10 16V 1055 5B475...

Страница 53: ...ppm 1150 4A4992FP R35 RES SM 1K00 0805 1 100ppm 1150 3A1001FP R36 POT SM 4mmSQ 50K MUL TRN SIDE 1174 DM3503J0 R37 RES SM 49K9 0805 1 100ppm 1150 4A4992FP R38 POT SM 4mmSQ 5K0 MUL TRN SIDE 1174 DM2502J...

Страница 54: ...ES SM 16K2 0805 1 100ppm 1150 4A1622FP R77 RES SM 20K0 0805 1 100ppm 1150 4A2002FP R78 RES SM 10K0 0805 1 100ppm 1150 4A1002FP R79 RES SM 49K9 0805 1 100ppm 1150 4A4992FP R80 RES SM 27K4 0805 1 100ppm...

Страница 55: ...sion 1 8 2 2 2 3 Audio Processors Issue 4 contains no AM information the document title is changed to reflect coverage of only FM transmitters 699 For VT 3H035 VT 3H045 transmitters to reduce spurious...

Страница 56: ...eferences 6113 VT 3 140 Audio Processor select value table updated 6115 VT 3 160 Audio Processor select value table updated 4 5 0 Feb 06 6129 UT 3 420 SXCX00 Audio Processor select value table updated...

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