Pulse generator
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This project report describes the development of a test jig for testing the MODE-S drawer of IFF equipment. Some key issues with current testing methods are the need to test using the full IFF system, which is time-consuming, and the lack of a standalone test solution for the MODE-S drawer. The proposed test jig includes a pulse generator circuit to generate trigger pulses, and interfaces to monitor signals and outputs from the MODE-S drawer unit. Use of the test jig is expected to reduce testing time and allow more efficient troubleshooting, resulting in estimated savings of over 300,000 rupees.
Pulse generator
- 1. PROJECT REPORT TITLE : PULSE GENERATOR WORK AREA : PA-C/T-II/IFF HELPING MEMBERS : MR. JYOTI PRAKASH LOG ON TO WWW.THOUGHTCRACKERS.BLOGSPOT.COM FOR MORE TECHNICAL STUFF. 1
- 2. 2 1. INTER-CHANGEBILITY PROBLEM OF PCBS/MODULES 2. NON AVALABILITY OF TEST JIG FOR IFF MODE-S TESTING 3. ALTERNATE TEST SET-UP FOR TX PULSE FREQ MEASUREMENT 4. NO INDIVIDUAL MAINS SWITCH FOR EACH TABLE 5. WORK AREA BECOMES DUSTY QUITE OFTEN. 6. NO PROPER SITTING ARRANGEMENT. 7. NO BACK-UP ARRANGEMENT FOR PC. 8. TESTING CYCLE TIME FOR IFF-FLYCATCHER. 9. NON-AVAILABILITY OF PRIMARY TRIGGER FOR IFF-SPAGU 10. DISTURBANCES DUE TO OPEN HANGER. PROBLEMS
- 3. 3 PROBLEMS contd….. 11. MAINTENANCE OF LIGHTING IN TESTING HANGER. 12. LACK OF MAINTENACE AND CLEANING OF WORK AREA 13. ELECTRICAL WIRING , SUPPLY SOCKETS AND SWITCHES ARE IN BAD CONDITION ON WORKING TABLE.S 14. IFF INTEGRATION PROBLEMS AT SITE. 15. LOT OF NOISE DISTURBANCE IN WORK AREA 16. FREQUENT FAILURE OF 400 W TPA. 17. NO PROPER STORAGE OF UNUSED INSTRUMENTS. 18. NO CENTRALISED STORAGE OF ACCESSORIES. 19. ADJUSTMENT RF POWER AT SYSTEM LEVEL
- 4. 4 SELECTION OF THEME THROUGH BRAIN STORMING MEMBER DECIDED TO SELECT A PRODUCT RELATED PROBLEM
- 5. 5 a. Interchangeability problem of PCB’s and modules. b. Frequent failure problem of 400 W TPA c. Testing cycle time of IFF Flycatcher. d. IFF integration problem at site. e. Non availability of test jig for IFF MODE-S TESTING f. Adjustment of RF Power at system level
- 6. 6 1. MODE-S DRAWER WAS ADDED IN THE EXISTING IFF MK-X EQUIPMENT OF IFF - REPORTER. 2. MODE-S IS DEVELOPED FOR INDIAN DEFENCE SEVICES FOR SECURE MODE OF IDENTIFICATION. IT IS A SELECTIVE TYPE INTERROGATION USED TO MAINTAIN SECRECY OF AIR CRAFT’S CODE. 3. ENCRYPTION (POLY & KEY) IS USED WHILE INTERROGATING IN MODE-S. THE REPLY CONSISTS OF AIR CRAFT CODE (POLY+KEY) OF 8.5 µS FRAME INTRODUCTION
- 7. 7 MODE-S DRAWER CRO MODE – S DRAWER TESTING (VARIOUS ALTERNATIVES) AC MAINS SUGGESTION: SYSTEM LEVEL INTEGRATION THE MODE-S DRAWER CAN BE TESTED AS A TOTAL SYSTEM INTERCONNECTING WITH IFF INT-DEC MK-X DRAWER AC MAINS OUT PUT
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- 9. MODE – S DRAWER TESTING (VARIOUS ALTERNATIVES) LIMITATIONS: (i) MORE TIME REQUIRED, (ii) DIFFICULTY IN TROUBLE SHOOTING PCBS & MODULES (iii) HOLDING ONE EQUIPMENT(INT-DEC) (iv) DIFFICULTY IN TROUBLE SHOOTING ON REAR PANEL SIDE MODULES MOTHER BOARD & POWER SUPPLIES. 9
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- 11. 11 PULSE GEN MODE ‘S’ UNIT UNDER TEST CRO SUGGESTION : TEST SET-UP FOR TESTING OF MODE-S DRAWER INDEPENDENTLY AC MAINS 115 V, 400 HZ MODE-S CHALLENGE TX PULSES O/P SIM O/P MODE-S ZRP O/P VIDEO O/P PRE-TRIG POWER SUPPLY MODE-S ON RAW VIDEO LIMITATIONS: 1) SET-UP IS BULKY 2) HAVING MORE LOOSE CONNECTIONS 3) REQUIRES MORE TEST EQUIPMENTS 4) INADEQUACY TO CHECK ALL PARAMETERS
- 12. ACTIVITIES: Design of MODE-S test jig for PCBs & drawer testing which should incorporate the following features:- 1 Adjustable PRT , Pulse width. Pulse generator for generation of pre trigger signal. 2. +5 volt power supply for Challenge command and for trouble shooting purposes 3. Checking the interfacing of MODE-S & MK-X (Int- Dec) units. 4. Monitoring of interface signals. 12
- 13. 13 PULSE GENERATOR CIRCUIT Diagram 54 LS 123 / A 15 KΩ 100 K Ohms PRT Adj 56 KΩ 10 K PW Adj 100 PF 47 KPF 1 2 3 14 15 13 4 9 10 11 6 7 5 12 54 LS123 / B VCC VCC GND 54 LS 37 BUFFER 1,2 6 PW : 0.8 µs, PRT : 2.2 ms O / P Amp .3.5 V 3 5 7
- 14. 14 MODE ‘S’ TEST JIG EXT O/P + 5 V PULSE GEN CKT Specs: Pw 0.5µs, Prt : 2,2mS, Amp: .3.5V 1 2 3 2 4 1 7 8 MODE ‘S’ INTERFACE MODE’S’ MATCH VIDEO MODE’S’ TX PULSES PRE TRIGGER MODE S ZRP CHALLENGE CONTROL AC MAINS 5 V, 5A POWER SUPPLY 9 GND + 5 V GND GND + 5V GND + 5V + 5V + 5V S 1 S 2 S 2 PRE TRIGGER + 5 V + 5 V
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- 16. TEST SET-UP 16 MODE-S UNIT TEST - JIG CRO CONNECTOR INTERFACE CABLE
- 17. 17 TEST PROCEDURE 1. CONNECT THE TEST JIG AS PER THE SET UP. 2. CHECK THE +5V OUTPUT 3. SWITCH ON S-1 & OBSERVE THE ‘PRE TRIGGER OUTPUT’ ON CRO. 4. SWITCH ON S-2 & OBSERVE THE ‘MODE PULSES OUTPUT’ ON CRO. 5. SWITCH ON SIM ON MODE-S DRAWER & OBSERVE THE ‘MODE-S MATCH LED ON’. 6. OBSERVE ‘MODE-S VIDEO’ ON CRO FOR 70 + 5 µS.
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- 19. 19 1. AVOID THE USE OF PULSE GENERATOR EXCLUSIVELY FOR MODE-S TESTING.( 1 lac approx) 2. AVAILABILITY OF + 5 V DEDICATED POWER SUPPLY FOR TROUBLE SHOOTING. 3. USE OF AVAILABLE COMPONENTS. 4. AVOIDING MK-X SYSTEM FOR TESTING. 5. MAN-HOUR TESTING REDUCED FROM 48 Hrs TO 40 Hrs MAN HOURS SAVED 8Hrs / UNIT (15 x 8 = 120 x 1023 = Rs. 122760/-) 6. MAN-HOUR TESTING REDUCED FROM 24 HrsTO 20 Hrs. MAN HOURS SAVED 4Hrs / SPARES / SET(5x4=20x1023=Rs. 2460/- 7. EASY TO CARRY TO SITES FOR REPAIR JOB AND SAVINGS OF TA/DA ( Rs. 1 lac approx) 8. TOTAL SAVINGS OF Rs : 325220/- BENEFITS (TANGIBLE)
- 20. 20 1. NEAT TEST SET-UP 2. EASE IN TESTING/TROUBLE SHOOTING AT BENCH LEVEL. 3. COMPLETE TESTING OF ALL PARAMETERS AT BENCH LEVEL. 4. STAND ALONE TESTING WITHOUT HOLDING IFF EQUIPMENT. 5. PARALLEL TESTING ARE POSSIBILE. 6. CLEARANCE OF SPARES AT BENCH LEVEL. BENEFITS (INTANGIBLE)