Future scope modulation and demodulation
Answers
Answered by
1
With QPSK, the carrier undergoes four changes in phase (four symbols)and can thus represent 2 binary bits of data per symbol.
A modulation scheme that enables a carrier to transmit 2 bits of information instead of 1.
Effectively doubles the bandwidth of the carrier.
The phase shift on a carrier can be demodulated into a varying output voltage by multiplying the carrier with a sine-wave local oscillator and filtering out the high-frequency term.
To accurately decode phase shifts present in all four quadrants, the input signal needs to be multiplied by both sinusoidal and co-sinusoidal wave forms.
The high frequency needs filtering out, and the data reconstructed.
Removing the data from the carrier is a simple process of low pass filtering the output of the mixer and reconstructing the four voltages back into logic levels.
The output of the front end de-modulator is normally fed into an ADC and any rotation resulting from errors in the phase or frequency of the local oscillator are removed in DSP.
An effective way of converting directly to base band is using a direct-conversion tuner IC.
In recent years, short-to-medium range personal wireless connectivity has played an increasingly signicant role in wireless communications systems. Ultra wide band (UWB) technology based primarily on the impulse radio paradigm has a huge potential for revolutionizing the world of digital communications especially wireless communications.
Although the increasing need of high data rates in wireless communication applications will require the use of wide band systems capable of handling several GHz in order to accomplish the demands. Consequently, UWB technology has emerged as a solution for high data rates system.
Furthermore, UWB is characterized by low power transmission, potential for low-cost and simple transceiver design, high resolution, easier material penetration, immunity to multipath effects and robustness against eaves dropping.
Hence it is very challenging taskto design UWB transceiver system which provides high-capacity, high data rate,power-efficient and small transceiver design.
With this perspective the thesis deals with the analysis, the design and the simulation of a UWB system to suggest new architectures for UWB receiver. The UWB receiver is non-coherent and uses the Energy Detection approach. The main peculiarity of this research is the implementation of two types of LNAs in the CMOS technology and its impact on the performance of various types pulse modulation schemes along with more realistic channel model for UWB. This UWB system is intended as a low-cost solution, by implementing its analog-front-end using the Energy Detection scheme, an Integrate and Dump unit.
The theoretical receiver formation focusing on its main blocks is formulated for coherent and non-coherent receiver. In the thesis theoretical analysis is prepared for coherent as well as non coherent detection with BPSK, PPM and PPV modulation schemes considering AWG N channel.
A detailed analysis for BPSK, PPM, and PPV is performed for bit error rate calculation. It is demonstrated that the performance is not only dependent on modulation 134 scheme and detection method it uses but also on the normalized auto correlation function of the received signal.
A modulation scheme that enables a carrier to transmit 2 bits of information instead of 1.
Effectively doubles the bandwidth of the carrier.
The phase shift on a carrier can be demodulated into a varying output voltage by multiplying the carrier with a sine-wave local oscillator and filtering out the high-frequency term.
To accurately decode phase shifts present in all four quadrants, the input signal needs to be multiplied by both sinusoidal and co-sinusoidal wave forms.
The high frequency needs filtering out, and the data reconstructed.
Removing the data from the carrier is a simple process of low pass filtering the output of the mixer and reconstructing the four voltages back into logic levels.
The output of the front end de-modulator is normally fed into an ADC and any rotation resulting from errors in the phase or frequency of the local oscillator are removed in DSP.
An effective way of converting directly to base band is using a direct-conversion tuner IC.
In recent years, short-to-medium range personal wireless connectivity has played an increasingly signicant role in wireless communications systems. Ultra wide band (UWB) technology based primarily on the impulse radio paradigm has a huge potential for revolutionizing the world of digital communications especially wireless communications.
Although the increasing need of high data rates in wireless communication applications will require the use of wide band systems capable of handling several GHz in order to accomplish the demands. Consequently, UWB technology has emerged as a solution for high data rates system.
Furthermore, UWB is characterized by low power transmission, potential for low-cost and simple transceiver design, high resolution, easier material penetration, immunity to multipath effects and robustness against eaves dropping.
Hence it is very challenging taskto design UWB transceiver system which provides high-capacity, high data rate,power-efficient and small transceiver design.
With this perspective the thesis deals with the analysis, the design and the simulation of a UWB system to suggest new architectures for UWB receiver. The UWB receiver is non-coherent and uses the Energy Detection approach. The main peculiarity of this research is the implementation of two types of LNAs in the CMOS technology and its impact on the performance of various types pulse modulation schemes along with more realistic channel model for UWB. This UWB system is intended as a low-cost solution, by implementing its analog-front-end using the Energy Detection scheme, an Integrate and Dump unit.
The theoretical receiver formation focusing on its main blocks is formulated for coherent and non-coherent receiver. In the thesis theoretical analysis is prepared for coherent as well as non coherent detection with BPSK, PPM and PPV modulation schemes considering AWG N channel.
A detailed analysis for BPSK, PPM, and PPV is performed for bit error rate calculation. It is demonstrated that the performance is not only dependent on modulation 134 scheme and detection method it uses but also on the normalized auto correlation function of the received signal.
Similar questions