Phaselock Techniques – Floyd M. Gardner [Book review]

The author, Floyd M. Gardner an influential expert in the area of PLLs, has presented a good reference book that encompasses all the theoretical and mathematical concepts for the phase locked loop (PLL) design. The collection of topics in this book provides an excellent source of information to researchers and engineers for understanding and application … Read more

Model a Frequency Selective Multipath Fading channel

A brief intro to modeling a frequency selective fading channel using tapped delay line (TDL) filters. Rayleigh & Rician frequency-selective fading channel models explained. Tapped delay line filters Tapped-delay line filters (FIR filters) are best to simulate multiple echoes originating from same source. Hence they can be used to model multipath scenarios. Tapped-Delay-Line (TDL) filters with … Read more

Plot histogram and estimated PDF in Matlab

Key focus: With examples, let’s estimate and plot the probability density function of a random variable using Matlab histogram function. Generation of random variables with required probability distribution characteristic is of paramount importance in simulating a communication system. Let’s see how we can generate a simple random variable, estimate and plot the probability density function … Read more

Cyclic Prefix in OFDM: hands-on demo in Matlab

Synopsis: Cyclic prefix in OFDM, tricks a natural channel to perform circular convolution. This simplifies equalizer design at the receiver. Hands-on demo in Matlab. Cyclic Prefix-ed OFDM A cyclic-prefixed OFDM (CP-OFDM) transceiver architecture is typically implemented using inverse discrete Fourier transform (IDFT) and discrete Fourier transform (DFT) blocks (refer Figure 13.3). In an OFDM transmitter, … Read more

Logical Effort

Key focus: Discuss the definition of logical effort, the idea behind it and various associated terminologies. Introduction In today’s digital world the most important aspect of any processor is how fast can it function and support multiple applications. Often, the chip design engineers are confronted with bewildering questions in the design process of a logic: … Read more

Interpret FFT results – obtaining magnitude and phase information

In the previous post, Interpretation of frequency bins, frequency axis arrangement (fftshift/ifftshift) for complex DFT were discussed. In this post, I intend to show you how to interpret FFT results and obtain magnitude and phase information. Outline For the discussion here, lets take an arbitrary cosine function of the form \(x(t)= A cos \left(2 \pi … Read more

Interpret FFT, complex DFT, frequency bins & FFTShift

Key focus: Interpret FFT results, complex DFT, frequency bins, fftshift and ifftshift. Know how to use them in analysis using Matlab and Python. Four types of Fourier Transforms: Often, one is confronted with the problem of converting a time domain signal to frequency domain and vice-versa. Fourier Transform is an excellent tool to achieve this … Read more

Significance of RMS (Root Mean Square) value

Root Mean Square (RMS) value is the most important parameter that signifies the size of a signal. Defining the term “size”: In signal processing, a signal is viewed as a function of time. The term “size of a signal” is used to represent “strength of the signal”. It is crucial to know the “size” of … Read more

Physical Telepresence : The future of communication.

We live in the age of smart phones that can be loaded with numerous applications to communicate with each other. What’s next ? Where do we go from here ? Students at MIT Media Labs has answered the call with a novel approach of “Physical Telepresence” that provides the ability to remotely render shapes of … Read more