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![Agenda ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],QPSK Modulator December 16, 2010](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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- 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)
- 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. 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. QPSK Modulator Time Domain Description of QPSK Modulator December 16, 2010
- 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. QPSK Modulator Upsampling Matlab Simulation of QPSK Modulator December 16, 2010
- 12. QPSK Modulator I - Signal Modulation Matlab Simulation of QPSK Modulator December 16, 2010
- 13. QPSK Modulator Q Signal Modulation Matlab Simulation of QPSK Modulator December 16, 2010
- 14. QPSK Modulator QPSK Time Domain Signal Matlab Simulation of QPSK Modulator December 16, 2010
- 15. QPSK Modulator Baseband Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
- 16. QPSK Modulator QPSK Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
- 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. QPSK Modulator QPSK Spectrum Matlab Simulation of QPSK Modulator December 16, 2010
- 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
- 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
- 27. QPSK Modulator I & Q Carrier Signal Generation Hardware Implementation of QPSK Modulator December 16, 2010
- 28. QPSK Modulator Simulated Implemented QPSK Modulated Signal Hardware Implementation of QPSK Modulator December 16, 2010
- 29. QPSK Modulator QPSK Spectrum Hardware Implementation of QPSK Modulator December 16, 2010
- 30. QPSK Modulator Simulated Implemented QPSK Spectrum : Results December 16, 2010
- 31. QPSK Modulator Hardware Setup : Results December 16, 2010
- 35. Thanks
Notas do Editor
- 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 & 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 & 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 & Q modulated signal we get qpsk modulated signal. here we can see phase shift 45,135,225 & 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 & Q carrier out of 90 degree phase is generated. QPSK Modulator