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PHASE & AMPLITUDE STABILITY STUDY OF 200MHz T0 800MHz LNA FOR GMRT

PHASE & AMPLITUDE STABILITY STUDY OF 200MHz T0 800MHz LNA FOR GMRT. by ARNAB MANDAL arnab_science@yahoo.com UNDER GUIDENCE OF Mr. A.Praveen Kumar. OUTLINE OF THE TALK. Introduction Basics of amplifier Noise measurement Theoretical calculation

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PHASE & AMPLITUDE STABILITY STUDY OF 200MHz T0 800MHz LNA FOR GMRT

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  1. PHASE & AMPLITUDE STABILITY STUDY OF 200MHz T0 800MHz LNA FOR GMRT by ARNAB MANDAL arnab_science@yahoo.com UNDER GUIDENCE OF Mr. A.Praveen Kumar

  2. OUTLINE OF THE TALK • Introduction • Basics of amplifier • Noise measurement • Theoretical calculation • Data acquisition • Plot by MATLAB • Analysis of graph • Further improvement

  3. INTRODUCTION • Determination of imbalance of the two LNA's • Study of gain ratio • Study of phase change

  4. BASICS OF AMPLIFIER • Gain G (dB) =10log (Pout/Pin) =20log (Vout/Vin)

  5. BASICS OF AMPLIFIER • Noise Noise figure: F= SNRin/SNRout =PNout/PNin Noise figure: F=10log(NF)

  6. BASICS OF AMPLIFIER Friis' formula Noise temperature Friis formula for noise temperature

  7. NOISE MEASUREMENT • By Noise figure analyzer

  8. NOISE MEASUREMENT

  9. NOISE MEASUREMENT • Optimization of gain Gain approximately 26db Noise temperature below 40 Kelvin

  10. THEORETICAL CALCULATION • Block diagram with LNA SIGNAL GENAR-ATOR VECTOR VOLT- METRE LAPTOP 3DB SPLITTER LNA1 LNA2

  11. THEORETICAL CALCULATION • After 3db splitter X1=X *A1 *ej1 X2=X*A2 *ej2 • After LNAs X3 =X1 *G1 *ej1 X4=X2 *G2 *ej2 |B/A|=[G2 *ACABLE 2 *A CHANNEL 2]/[G1*ACABLE 1 *A CHANNEL 1] Phase part: B-A= (Phase change) LNA+ (Phase change) SPLITTER +(Phase change) CABLE

  12. SIGNAL GENAR-ATOR VECTOR VOLT- METRE LAPTOP 3DB SPLITTER THEORETICAL CALCULATION • Block diagram without LNA

  13. THEORETICAL CALCULATION • Experiment without LNAs gives the (B’/A’ )WITHOUT LNA & B’-A’=(Phase change)SPLITTER+ (Phase change)CABLE

  14. DATA ACQUISITION • Done by LABVIEW program Total time taken=15*900*13 seconds =175500 seconds =48.75 hours. Data was taken for 48.75 hours

  15. PLOT BY MATLAB • Figure 1

  16. PLOT BY MATLAB • Figure 2

  17. PLOT BY MATLAB • Figure 3

  18. PLOT BY MATLAB • Figure 4

  19. PLOT BY MATLAB • Figure 5

  20. PLOT BY MATLAB • Figure 6

  21. 2nd EXPERIMENT Experiment: 1 Experiment: 2

  22. 2nd EXPERIMENT Experiment: 1 Experiment: 2

  23. FURTHER IMPROVEMENT • Reduction of cable losses • Cause of gain difference • Measurement error

  24. Thank You

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