The presentation describes the basic synchronization Issues in OFDM like STO and CFO and their estimation techniques using Maximum Likelihood Detection
Analyse Performance of Fractional Fourier Transform on Timing and Carrier Fr...ijwmn
This paper deals with the performance of the use of fractional Fourier transform (FRFT) instead of
conventional Fourier transform (FFT) in either symbol timing offset (STO) and carrier frequency offset
(CFO) estimation. Orthogonal frequency division multiplexing is widely used in many systems due to
advantages of theses technique compared with mono-carrier systems. In spite of his advantages, OFDM
presents drawbacks such as sensitivity to timing and frequency offsets. Many techniques are used in the
literature to estimate these two parameters in order to compensate them (synchronization task). These
techniques used conventional Fourier transform. In this paper, we are interested in estimating STO and
CFO using fractional Fourier transform. Monte Carlo simulation demonstrates the performance of the use
of FRFT instead of FFT.
The discrete Fourier transform has many applications in science and engineering. For example, it is often used in digital signal processing applications such as voice recognition and image processing.
Use s parameters-determining_inductance_capacitancePei-Che Chang
1. Use s parameters-determining_inductance_capacitance
2. Relationship Between Common Circuits and the ABCD Parameters
3. Converts Z-parameters to S-parameters
4. Relationships Between Two-Port S and ABCD Parameters
5. Via and equivalent circuit
On The Fundamental Aspects of DemodulationCSCJournals
When the instantaneous amplitude, phase and frequency of a carrier wave are modulated with the information signal for transmission, it is known that the receiver works on the basis of the received signal and a knowledge of the carrier frequency. The question is: If the receiver does not have the a priori information about the carrier frequency, is it possible to carry out the demodulation process? This tutorial lecture answers this question by looking into the very fundamental process by which the modulated wave is generated. It critically looks into the energy separation algorithm for signal analysis and suggests modification for distortionless demodulation of an FM signal, and recovery of sub-carrier signals
The presentation describes the basic synchronization Issues in OFDM like STO and CFO and their estimation techniques using Maximum Likelihood Detection
Analyse Performance of Fractional Fourier Transform on Timing and Carrier Fr...ijwmn
This paper deals with the performance of the use of fractional Fourier transform (FRFT) instead of
conventional Fourier transform (FFT) in either symbol timing offset (STO) and carrier frequency offset
(CFO) estimation. Orthogonal frequency division multiplexing is widely used in many systems due to
advantages of theses technique compared with mono-carrier systems. In spite of his advantages, OFDM
presents drawbacks such as sensitivity to timing and frequency offsets. Many techniques are used in the
literature to estimate these two parameters in order to compensate them (synchronization task). These
techniques used conventional Fourier transform. In this paper, we are interested in estimating STO and
CFO using fractional Fourier transform. Monte Carlo simulation demonstrates the performance of the use
of FRFT instead of FFT.
The discrete Fourier transform has many applications in science and engineering. For example, it is often used in digital signal processing applications such as voice recognition and image processing.
Use s parameters-determining_inductance_capacitancePei-Che Chang
1. Use s parameters-determining_inductance_capacitance
2. Relationship Between Common Circuits and the ABCD Parameters
3. Converts Z-parameters to S-parameters
4. Relationships Between Two-Port S and ABCD Parameters
5. Via and equivalent circuit
On The Fundamental Aspects of DemodulationCSCJournals
When the instantaneous amplitude, phase and frequency of a carrier wave are modulated with the information signal for transmission, it is known that the receiver works on the basis of the received signal and a knowledge of the carrier frequency. The question is: If the receiver does not have the a priori information about the carrier frequency, is it possible to carry out the demodulation process? This tutorial lecture answers this question by looking into the very fundamental process by which the modulated wave is generated. It critically looks into the energy separation algorithm for signal analysis and suggests modification for distortionless demodulation of an FM signal, and recovery of sub-carrier signals
A very quick and easy to understand introduction to Gram-Schmidt Orthogonalization (Orthonormalization) and how to obtain QR decomposition of a matrix using it.
Comparative Analysis of Distortive and Non-Distortive Techniques for PAPR Red...IDES Editor
OFDM is a popular and widely accepted modulation
and multiplexing technique in the area of wireless
communication. IEEE 802.15, a wireless specification defined
for WPAN is an emerging wireless technology for short range
multimedia applications. Two general categories of 802.15
are the low rate 802.15.4 (ZigBee) and high rate 802.15.3
(UWB). In their physical (PHY) layer design, OFDM is a
competing technique due to the various advantages it renders
in the practical wireless media. OFDM has been a popular
technique for many years and adopted as the core technique
in a number of wireless standards. It makes the system more
immune to interference like InterSymbol Interference (ISI)
and InterCarrier Interference (ICI) and dispersive effects of
the channel. It is also a spectrally efficient scheme since the
spectra of the signal are overlapping in nature. Despite these
advantages OFDM suffers from a serious problem of high
Peak to Average Power. This limits the system’s capabilities
and increases the complexity. This paper compares the signal
distortion technique of Amplitude Clipping and the
distortionless technique of SLM for Peak to Average Power
reduction
For ease of analog or digital information transmission and reception, modulation is the foremost important technique. In the present project, we’ll discuss about different modulation scheme in digital mode done by operating a switch/ key by the digital data. As we know, by modifying basic three parameters of the carrier signal, three basic modulation schemes can be obtained; generation and detection of these three modulations are discussed and compared with respect to probability of error or bit error rate (BER).
1. 1
TELE3113 Analogue and Digital Communications
Tutorial 5
I. P ROBLEM 1
1) Draw diagrams showing a Delta Modulator (DM).
2) Explain how DM works. Illustrate your answer with diagrams showing a typical waveform for the analogue
signal and the delta modulated signal.
3) Explain slope overload in relation to DM.
4) Describe Adaptive Delta Modulation (ADM) and how the ADM reduce the effects of slope overload.
II. P ROBLEM 2
1) Draw diagrams showing a Differential Pulse Code Modulation (DPCM).
2) Explain how DPCM differs from PCM.
III. P ROBLEM 3
Consider the following binary sequence, 101011.
1) Draw a Binary Phase Shift Keying (BPSK) waveform for this sequence.
2) Draw diagrams of Differential Phase Shift Keying (DPSK) generator and demodulator.
3) Differentially encode the sequence. Assume an initial reference bit is 1.
4) Show how DPSK removes the 180◦ phase ambiguity.
5) If 4-ary Amplitude Shift Keying (ASK) is used for the modulation, sketch the modulated wave corresponding
to the sequence. Assume the amplitude levels to be ±1 V and ±3 V.
IV. P ROBLEM 4
Two analogue signals, of bandwidth 3 KHz and 6 KHz, are to be time division multiplexed (TDM) with three
digital sources of data rates of 6000 bps. The analogue signals are to be transmitted as 4-bit PCM signals.
1) Choose appropriate sampling frequencies for the analogue signals. What will be their corresponding data
rates?
2) Design a TDM system to multiplex these five signals. Sketch a diagram illustrating the multiplexer and
demultiplexer.
3) What is the data rate of the TDM signal?