Upload
avari
View
46
Download
3
Tags:
Embed Size (px)
DESCRIPTION
A QPSK Modulator Using Microwave Couplers and Switches for Satellite Transmitter and Its Performance Analysis. Course: Digital Communication and Coding Professor: Dr. Tareq AlNafouri Presented By: Farhan Abdul Ghaffar. QPSK MODULATION. INTRODUCTION WHY QPSK MODULATION? - PowerPoint PPT Presentation
Citation preview
A QPSK Modulator Using Microwave Couplers and Switches for Satellite Transmitter and Its
Performance Analysis
Course: Digital Communication and CodingProfessor: Dr. Tareq AlNafouri
Presented By: Farhan Abdul Ghaffar
QPSK MODULATION• INTRODUCTION
• WHY QPSK MODULATION?REMOTE SENSING PURPOSES
X BAND 8 GHz to 12 GHz
DESIGN OF THE MODULATOR
THEORY OF THE MODULATORCIRCUIT ELEMENTS
• MICROWAVE COUPLERS
POWER DIVISIONPHASE SHIFTS PARAMETERS
• HIGH SPEED MESFET SWITCHES
MICROWAVE COUPLERS
• WILKINSON DIVIDER
• THREE PORT ELEMENT
EQUAL POWER DIVISION
S21 = S31= -3dB
NO PHASE SHIFTS21= S31
• BRANCH LINE HYBRID COUPLER
• FOUR PORT ELEMENT
EQUAL POWER DIVISIONS21 = S31= -3dB
QUADRATURE PHASE SHIFTS31- S21 = 90
• RAT RACE COUPLER
• FOUR PORT ELEMENT
EQUAL POWER DIVISION
S23 = S13= -3dB
180 PHASE SHIFT
S23- S13 = 180
STRUCTURE and WORKING
TESTING AND MEASUREMENT
• DATA RATE = 160Mbps• PHASE IMBALANCE = 0.4• AMPLITUDE IMBALANCE < 1%• EVM = 0.75%
PERFORMANCE ANALYSIS• AMPLITUDE IMBALANCE
• PHASE IMBALANCE
• ERROR VECTOR MAGNITUDE
EVM OF MODULATOR WITH AMPLIFIERS
• EVM OF THE TRANSMITTER < 8%
EVM vs. BER
• To keep the value of EVM minimum we need S parameters to be as optimized as possible.
EVM and SNR
• Lesser EVM will give greater SNR and lesser Probability of Error
HARDWARE OF THE MODULATOR
Q & A Session