Hardware Implementation of QPSK Modulator for Satellite Communication Presented By : Kiran Prajapati Pradeep Santdasani In...
Agenda  <ul><li>Overview of Satellite Communication </li></ul><ul><li>Overview of Digital Modulation </li></ul><ul><li>Des...
<ul><li>Digital Modulation schemes are used in Satellite Communication Systems. </li></ul>Overview of Satellite Communicat...
Overview of Digital Modulation <ul><li>Any features of a carrier signal – amplitude, frequency, or phase can be digitally ...
<ul><li>An M-phase PSK modulator puts the phase of carrier into one of M - states according to the value of a input . </li...
QPSK Modulator I data Q data + Cos  ω c t   Modulator Output Block Diagram sin  ω c t   I - Signal 1 bit = 180  o 0 bit = ...
QPSK Modulator Equations I - Signal sin ( ω c t - 45 ) Q - Signal -cos  ω c t Phasor Diagram +cos  ω c t +sin  ω c t -sin ...
QPSK Modulator Time Domain Description of QPSK Modulator December 16, 2010
Steps of Project Implementation <ul><li>Matlab Simulation </li></ul><ul><li>Simulation on Xilinx FPGA </li></ul><ul><li>Im...
QPSK Modulator Unipolar  to  Bipolar Upsampling Carrier Unipolar  to  Bipolar Upsampling 90 o I data Q data Multiplier Mul...
QPSK Modulator Upsampling Matlab Simulation of QPSK Modulator December 16, 2010
QPSK Modulator I - Signal Modulation Matlab Simulation of QPSK Modulator December 16, 2010
QPSK Modulator Q Signal Modulation Matlab Simulation of QPSK Modulator December 16, 2010
QPSK Modulator QPSK Time Domain Signal Matlab Simulation of QPSK Modulator December 16, 2010
QPSK Modulator Baseband Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
QPSK Modulator QPSK Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
<ul><li>It is used for band limit the signal bandwidth . </li></ul><ul><li>The  objective is to create a pulse that resemb...
QPSK Modulator Unipolar  to  Bipolar Upsampling Carrier Unipolar  to  Bipolar Upsampling 90 o I data Q data Shaping Shapin...
QPSK Modulator QPSK Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
QPSK Modulator Carrier Frequency  ƒc = 25 MHz Data Frequency  ƒd = 25 MHz Roll off Factor  α   =  0.3   Bandwidth = 16.25 ...
<ul><li>DSP algorithm has sum of products of equations </li></ul><ul><li>DSP systems are required to perform intensive ari...
<ul><li>It consists of I/O buffers, an array of configuration logic blocks and programmable interconnect structures.  </li...
<ul><li>Virtex 4 development kit is based on the  4VSX35 FPGA </li></ul><ul><li>SX family is focused for DSP  applications...
<ul><li>The Integrated Software Environment (ISE) is the Xilinx design software suite that allows taking design from desig...
QPSK Modulator I data + Look Up Table  sinw c t  I Carrier Q Carrier Shaping filter Unipolar to  bipolar Shaping filter Un...
<ul><li>The lookup-table method is technique used for generating periodic waveforms.  </li></ul><ul><li>It  involves readi...
QPSK Modulator I & Q Carrier Signal Generation Hardware Implementation of QPSK Modulator December 16, 2010
QPSK Modulator Simulated Implemented QPSK Modulated Signal Hardware Implementation of QPSK Modulator December 16, 2010
QPSK Modulator QPSK Spectrum Hardware Implementation of QPSK Modulator December 16, 2010
QPSK Modulator Simulated Implemented QPSK Spectrum : Results December 16, 2010
QPSK Modulator Hardware Setup : Results December 16, 2010
Conclusion <ul><li>QPSK modulator has been successfully implemented on the Xilinx Virtex – 4 Development kit. QPSK Modulat...
<ul><li>QPSK Demodulator </li></ul><ul><li>Multi Carrier QPSK Modulator  </li></ul><ul><li>Higher Order Digital Modulator ...
<ul><li>Modern Digital and Analog Communication Systems By B.P. LATHI </li></ul><ul><li>Satellite Communication  By Willia...
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  • We are doing project in space application centre(isro) at ahmedabad. Our project is QPSK modulator QPSK Modulator
  • Agenda of my presentation is , first we will explain theoretical portion , simulation and implementation on hardware QPSK Modulator
  • Digital mod is used to tx digital data , xxxxxxxxxxxxxxxxxxxxxxx it has three type. xxxxxxxxxxxxxxxxxxxxxxxxxxx QPSK Modulator
  • PSK can be classified on the basis of states . If transmits 1 bit as symbol than it is bpsk , likewise QPSK &amp; 8psk -------------------------- ------------ Here occupied bandwidth is same for all types of PSKs . In this way with the increase in state , it can transmit more data in same bandwidth. So it can uses bandwidth efficiently QPSK Modulator
  • This is typical qpsk mod block diagram. It has two 90 degree out of phase carrier. It transmits two bit as one symbol . So even bit is given to q nm odd is given to I . I carrier is multiplied with I data n Same way in Q . I &amp; Q modulated signal is added later. QPSK Modulator
  • QPSK Modulator
  • It is ideal QPSK modulated Spectrum QPSK Modulator
  • This is the way , we have followed in implementation of project QPSK Modulator
  • This is the block diagram of qpsk modulator for matlab simulation. QPSK Modulator
  • Here first unipolar data is converted into bipolar form ,which is shown in fig.1. to match the data and carrier samples ,upsampling of data is required . Here carrier frequency is three times than data frequency so one symbol is transmitted in three cycles. ---------- when the data transition occur from one state to another state, correspondingly the phase is shifted by 180 degree.------------------------ Same way q signal is modulated QPSK Modulator
  • Here first unipolar data is converted into bipolar form ,which is shown in fig.1. to match the data and carrier samples ,upsampling of data is required . Here carrier frequency is three times than data frequency so one symbol is transmitted in three cycles. ---------- when the data transition occur from one state to another state, correspondingly the phase is shifted by 180 degree.------------------------ Same way q signal is modulated QPSK Modulator
  • Here first unipolar data is converted into bipolar form ,which is shown in fig.1. to match the data and carrier samples ,upsampling of data is required . Here carrier frequency is three times than data frequency so one symbol is transmitted in three cycles. ---------- when the data transition occur from one state to another state, correspondingly the phase is shifted by 180 degree.------------------------ Same way q signal is modulated QPSK Modulator
  • By summing I &amp; Q modulated signal we get qpsk modulated signal. here we can see phase shift 45,135,225 &amp; 315 degrees in qpsk modulated signal QPSK Modulator
  • It is baseband spectrum . Any rectangular signal requires infinite bandwidth. QPSK Modulator
  • Baseband spectrum is shifted to carrier freq. Modulated spectrum occupies infinite bandwidth which is practically not possible. It requires filtering. QPSK Modulator
  • =------ here shaping is done on baseband data signal. It suppresses high frequency content . It also avoids ISI. QPSK Modulator
  • Shaping is done on upsampled data QPSK Modulator
  • After proper shaping side lobes can be suppressed . So limited bandwidth can be used for transmission purpose. QPSK Modulator
  • Here QPSK is implemented on FPGA kit. QPSK Modulator
  • Here we have used Xilinx FPGA. SX family is optimized for DSP application. To implement DSP algorithms , MAC operations are must . SX family has dedicated multipliers n adders for dsp appl. QPSK Modulator
  • This Diagram is implemented on hardware. Carrier is generated by look up table method QPSK Modulator
  • Same I &amp; Q carrier out of 90 degree phase is generated. QPSK Modulator
  • Saccolfinal 090505095735-phpapp01

    1. 1. Hardware Implementation of QPSK Modulator for Satellite Communication Presented By : Kiran Prajapati Pradeep Santdasani Internal Guide : Dhara Shah Lecturer (EC Dept.) L C Institute of Tech . External Guide : E P Balasubramanian Group Director SPSG Space Application Center (ISRO)
    2. 2. Agenda <ul><li>Overview of Satellite Communication </li></ul><ul><li>Overview of Digital Modulation </li></ul><ul><li>Description of QPSK Modulator </li></ul><ul><li>Steps of Project Implementation </li></ul><ul><li>Matlab Simulation of QPSK Modulator </li></ul><ul><li>Hardware Implementation of QPSK Modulator </li></ul><ul><li>Results </li></ul><ul><li>Conclusion </li></ul><ul><li>Future Scope </li></ul>QPSK Modulator December 16, 2010
    3. 3. <ul><li>Digital Modulation schemes are used in Satellite Communication Systems. </li></ul>Overview of Satellite Communication QPSK Modulator December 16, 2010
    4. 4. Overview of Digital Modulation <ul><li>Any features of a carrier signal – amplitude, frequency, or phase can be digitally modulated . </li></ul><ul><li>ASK = Amplitude Shift Keying </li></ul><ul><li>FSK = Frequency Shift Keying </li></ul><ul><li>PSK = Phase Shift keying </li></ul>QPSK Modulator December 16, 2010
    5. 5. <ul><li>An M-phase PSK modulator puts the phase of carrier into one of M - states according to the value of a input . </li></ul><ul><li>By increasing states , it can transmit more data in same bandwidth </li></ul>QPSK Modulator Data BPSK QPSK 8PSK Phase Shift Keying : Description of QPSK Modulator December 16, 2010
    6. 6. QPSK Modulator I data Q data + Cos ω c t Modulator Output Block Diagram sin ω c t I - Signal 1 bit = 180 o 0 bit = 0 o 0 bit = 90 o 00 bit = 45 o 10 bit = 315 o 01 bit =135 o 11 bit = 225 o Q - Signal 1 bit = 270 o Constellation Description of QPSK Modulator December 16, 2010
    7. 7. QPSK Modulator Equations I - Signal sin ( ω c t - 45 ) Q - Signal -cos ω c t Phasor Diagram +cos ω c t +sin ω c t -sin ω c t sin ( ω c t - 135 ) sin ( ω c t + 45 ) sin ( ω c t + 135 ) Description of QPSK Modulator December 16, 2010 I Data Q data I Mod O/P Q Mod O/P QPSK O/P QPSK O/P Phase 0 0 sin ω c t cos ω c t sin ω c t + cos ω c t = sin ( w c t + 45 ) 45˚ 0 1 sin ω c t -cos ω c t sin ω c t - cos ω c t = sin ( ω c t + 135) 135˚ 1 0 - sin ω c t cos ω c t - sin ω c t + cos ω c t = sin ( ω c t - 45 ) 315˚ 1 1 - sin ω c t -cos ω c t - sin ω c t - cos ω c t = sin ( ω c t - 135 ) 225˚
    8. 8. QPSK Modulator Time Domain Description of QPSK Modulator December 16, 2010
    9. 9. Steps of Project Implementation <ul><li>Matlab Simulation </li></ul><ul><li>Simulation on Xilinx FPGA </li></ul><ul><li>Implementation on Virtex – 4 </li></ul><ul><li>Testing and Debugging </li></ul>QPSK Modulator December 16, 2010
    10. 10. QPSK Modulator Unipolar to Bipolar Upsampling Carrier Unipolar to Bipolar Upsampling 90 o I data Q data Multiplier Multiplier Adder QPSK Modulator Block Diagram Matlab Simulation of QPSK Modulator December 16, 2010
    11. 11. QPSK Modulator Upsampling Matlab Simulation of QPSK Modulator December 16, 2010
    12. 12. QPSK Modulator I - Signal Modulation Matlab Simulation of QPSK Modulator December 16, 2010
    13. 13. QPSK Modulator Q Signal Modulation Matlab Simulation of QPSK Modulator December 16, 2010
    14. 14. QPSK Modulator QPSK Time Domain Signal Matlab Simulation of QPSK Modulator December 16, 2010
    15. 15. QPSK Modulator Baseband Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
    16. 16. QPSK Modulator QPSK Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
    17. 17. <ul><li>It is used for band limit the signal bandwidth . </li></ul><ul><li>The objective is to create a pulse that resembles the sin x/x shape. </li></ul><ul><li>So that receiver samples at intervals of Tb , where Tb is the bit period . </li></ul><ul><li>At the sampling instant , the “tails” from all preceding pulses have zero values </li></ul>QPSK Modulator Root Cosine Filter Matlab Simulation of QPSK Modulator December 16, 2010
    18. 18. QPSK Modulator Unipolar to Bipolar Upsampling Carrier Unipolar to Bipolar Upsampling 90 o I data Q data Shaping Shaping Multiplier Multiplier Adder QPSK Modulator Block Diagram Matlab Simulation of QPSK Modulator December 16, 2010
    19. 19. QPSK Modulator QPSK Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
    20. 20. QPSK Modulator Carrier Frequency ƒc = 25 MHz Data Frequency ƒd = 25 MHz Roll off Factor α = 0.3 Bandwidth = 16.25 MHz Matlab Simulation of QPSK Modulator QPSK Bandwidth December 16, 2010
    21. 21. <ul><li>DSP algorithm has sum of products of equations </li></ul><ul><li>DSP systems are required to perform intensive arithmetic operations such as multiplications and additions. </li></ul><ul><li>FPGAs can be used to implement DSP system as they provide tremendous computational power by using highly parallel architecture for high performance. </li></ul><ul><li>FPGAs dedicated for DSP has Embedded multipliers and distributed RAM for storage of coefficients. </li></ul>QPSK Modulator Digital Signal Processing (DSP) in FPGA : Hardware Implementation of QPSK Modulator December 16, 2010
    22. 22. <ul><li>It consists of I/O buffers, an array of configuration logic blocks and programmable interconnect structures. </li></ul><ul><li>Programming of the interconnect structure is accomplished by RAM cells whose o/p terminals are connected to the gates of MOS pass transistor </li></ul>QPSK Modulator Field Programmable Gate Array (FPGA) Hardware Implementation of QPSK Modulator December 16, 2010
    23. 23. <ul><li>Virtex 4 development kit is based on the 4VSX35 FPGA </li></ul><ul><li>SX family is focused for DSP applications </li></ul><ul><li>It has embedded multipliers which increases speed in MAC operations </li></ul>QPSK Modulator Virtex – 4 (SX Family) Hardware Implementation of QPSK Modulator December 16, 2010
    24. 24. <ul><li>The Integrated Software Environment (ISE) is the Xilinx design software suite that allows taking design from design entry through Xilinx device programming. </li></ul>QPSK Modulator Design Entry Synthesis Implementation Verification Device Configuration Xilinx ISE Hardware Implementation of QPSK Modulator December 16, 2010
    25. 25. QPSK Modulator I data + Look Up Table sinw c t I Carrier Q Carrier Shaping filter Unipolar to bipolar Shaping filter Unipolar to bipolar Q data QPSK Modulated Signal Look Up Table cosw c t QPSK Modulator Block Diagram Hardware Implementation of QPSK Modulator December 16, 2010
    26. 26. <ul><li>The lookup-table method is technique used for generating periodic waveforms. </li></ul><ul><li>It involves reading a series of stored data values that represent the waveform. </li></ul>QPSK Modulator Lookup Table Method Hardware Implementation of QPSK Modulator December 16, 2010
    27. 27. QPSK Modulator I & Q Carrier Signal Generation Hardware Implementation of QPSK Modulator December 16, 2010
    28. 28. QPSK Modulator Simulated Implemented QPSK Modulated Signal Hardware Implementation of QPSK Modulator December 16, 2010
    29. 29. QPSK Modulator QPSK Spectrum Hardware Implementation of QPSK Modulator December 16, 2010
    30. 30. QPSK Modulator Simulated Implemented QPSK Spectrum : Results December 16, 2010
    31. 31. QPSK Modulator Hardware Setup : Results December 16, 2010
    32. 32. Conclusion <ul><li>QPSK modulator has been successfully implemented on the Xilinx Virtex – 4 Development kit. QPSK Modulator is simulated in Matlab Software to verify and compare its functionality taking into account the limitations imposed by the hardware </li></ul><ul><li>The modulator algorithm has been implemented on FPGA using the VHSIC hardware description language (VHDL) on Xilinx ISE 8.2i. Simulated waveform is compared with actual output on the digital oscilloscope and spectrum analyzer. </li></ul><ul><li>The designed modulator may be used as a test bed for the functional verification of various RF subsystems which requires to be parameterized under modulated signal conditions </li></ul>QPSK Modulator December 16, 2010
    33. 33. <ul><li>QPSK Demodulator </li></ul><ul><li>Multi Carrier QPSK Modulator </li></ul><ul><li>Higher Order Digital Modulator and Demodulator </li></ul>QPSK Modulator The hardware module can be functionally extended to the following to support a variety of applications: Future Scope December 16, 2010
    34. 34. <ul><li>Modern Digital and Analog Communication Systems By B.P. LATHI </li></ul><ul><li>Satellite Communication By William Pratt </li></ul><ul><li>Contemporary Communication Systems using Matlab By John G. Proakis </li></ul><ul><li>VHDL Primer By J.Bhasker </li></ul><ul><li>Digital Systems Design with VHDL and Synthesis By K.C.Chang </li></ul><ul><li>User Guide of Xilinx ISE </li></ul><ul><li>Datasheet of Virtex - 4 </li></ul><ul><li>Datasheet of P240 Prototype Module </li></ul>QPSK Modulator References December 16, 2010
    35. 35. Thanks

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