Signals and systems demystified / David McMahonst ed. p. C. Includes index. ISBN (alk. paper). 1. Signal processing-Mathematical models. 2. 2 Signals and Systems: A First Look. System Classifications Discrete- Time Systems in the Time-Domain. .. Course PDF File: Currently Unavailable. Signals & Systems Demystified [David McMahon] on pettiremerhalf.ml *FREE* shipping on qualifying offers.
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signals and systems. DeMYSTİFieD. A SELF-TEACHING GUIDE. Master COMMUNICATIONS with details on. MODULATION and the Z-transform. Signals and Systems. Demystified. David McMahon. New York Chicago San Francisco Lisbon London Madrid. Mexico City Milan New Delhi San Juan Seoul. Signal Processing and Linear Systems, B.P. Lathi, CRC Press. • Other books. – Signals and Systems, Richard Baraniuk's lecture notes, available on line.
There are various ways to characterize filters; for example: A linear filter is a linear transformation of input samples; other filters are nonlinear. Linear filters satisfy the superposition principle , i. A causal filter uses only previous samples of the input or output signals; while a non-causal filter uses future input samples.
A non-causal filter can usually be changed into a causal filter by adding a delay to it. A time-invariant filter has constant properties over time; other filters such as adaptive filters change in time. A stable filter produces an output that converges to a constant value with time, or remains bounded within a finite interval. An unstable filter can produce an output that grows without bounds, with bounded or even zero input.
A finite impulse response FIR filter uses only the input signals, while an infinite impulse response IIR filter uses both the input signal and previous samples of the output signal. A filter can be represented by a block diagram , which can then be used to derive a sample processing algorithm to implement the filter with hardware instructions.
A filter may also be described as a difference equation , a collection of zeros and poles or an impulse response or step response. The output of a linear digital filter to any given input may be calculated by convolving the input signal with the impulse response. Main article: Frequency domain Signals are converted from time or space domain to the frequency domain usually through use of the Fourier transform.
The Fourier transform converts the time or space information to a magnitude and phase component of each frequency. With some applications, how the phase varies with frequency can be a significant consideration.
Biophysicists use a variety of techniques to measure conformational changes in biomolecules, to measure the energy associated with them and to determine the relationship between the various conformations and their biological function. It is also possible to induce conformational changes in the laboratory. These induced changes may or may not happen in nature. In either case, Chapter 2 B i o p h y s i c a l T o p i c s induced conformational transitions can further our understanding of the forces involved and can be used to develop medical treatments and diagnostics.
Ligand Binding and Intermolecular Binding A very common theme in subcellular biological function is the binding together of molecules. Sometimes the molecules are roughly equal in size and bind together to form a larger complex quaternary structure.
Each individual molecule in the complex is called a subunit. An example is hemoglobin, a large complex protein that carries oxygen from our lungs, through our blood, to the cells in our body.
Hemoglobin is made up of four subunit proteins that bind together. In other cases of molecular binding, a smaller molecule binds to a larger molecule.
In such cases we call the smaller molecule a ligand. A ligand is a smaller molecule or atom that binds to a larger molecule. The smaller molecule may be integral to the biological purpose of the larger molecule, or it may simply serve to activate or deactivate the larger molecule in carrying out its purpose.
When hemoglobin carries oxygen from the lungs to all of the cells in our body, oxygen molecules bind to the hemoglobin in the lungs. When oxygen binds to hemoglobin, the oxygen is considered a ligand. You should be aware, however, that sometimes the word ligand may be used in any case of two or more molecules binding together not just a smaller molecule binding to a larger one.
In this book we will use the term ligand to mean specifically the case where a smaller molecular or atom binds to a much larger molecule. We will use the more generic terms molecular binding, subunit binding, or simply binding to refer to cases where the size difference between the two molecules is not significant see Fig. The four subunits consist of two identical pairs of proteins.
One protein is called the alpha chain and the other is called the beta chain. The hemoglobin complex consists of two alpha chains and two beta chains. Molecular binding holds these four subunits together. Ligand binding occurs when oxygen binds to the hemoglobin. Each of the four subunits contains a group of atoms called heme. An oxygen molecule, acting as a ligand, binds to the iron atom within each subunit. In this way, one hemoglobin complex can bind up to four oxygen molecules.
Reprinted with permission of www. Diffusion and Molecular Transport This branch of biophysics studies how molecules move around within cells and how molecules move from outside a cell to inside the cell and vice versa. In fluids, molecules are continually moving, randomly colliding, and jostling about.
Diffusion is the process of molecules spreading out, as a result of this random motion.
By spreading out, we mean that the random motion will cause molecules to move from a region of higher concentration where they are closer together to one of lower concentration where they are further apart. The physics of diffusion can be described mathematically and can be used to better understand and predict biological activity in cells. Diffusion is the primary means of molecules moving around within a cell.
However, as we shall see, living systems also have several other means of moving molecules to where they are needed. Membrane Biophysics All living things are made up of cells.
The membrane is what defines the boundary between a cell and the outside world. These lipid bilayers are the main ingredient of cell membranes. Cell membranes are typically made of a double layer of lipid molecules. Lipids are fats or oils. The shape and physical characteristics of lipid molecules make them associate with each other stick together in the form of a bilayer two layers with the molecule heads on the outside of the bilayer and the string-like tails on the inside see Fig.
Membranes limit and control the movement of molecules into and out of the cell and from one region of the cell to another. Membranes are also able to create electrical potential across their surface, by controlling the flow of ions into and out 17 18 B i o p h y s i c s D e mys tifie d of the cell. Understanding the physics of lipids and membranes can help us to better understand and predict how cells will behave under various conditions. Membrane biophysicists often use lipid vesicles to study membranes.
A vesicle is a small hollow sac. Lipid vesicles are small hollow spheres of artificial membrane that can be made from various types of lipids.
Thus a lipid vesicle is like a cell with nothing inside it, just the membrane alone. This provides a simple tool to conduct experiments on the behavior of membranes without the complications of other parts of the cell.
It is possible to also place drugs or chemical agents inside lipid vesicles. Additionally, there are ways to attach certain molecules to the outer surfaces of such lipid vesicles to help the vesicles bind to specific sites in the body. In this way we can create targeted delivery systems to deliver drugs or chemicals to a specific location in the body for example, to the site of a tumor. By understanding the physics of lipid conformational transitions, we can control these conformational transitions, and thus control the ability of the lipid vesicles to contain the drug or chemical inside them.
Once the drug-filled lipid vesicles are in the bloodstream, we can apply a stimulus like heat or mild radiation to a specific part of the body to cause the lipid vesicles to release the drugs at that place. A closely related nucleic acid is RNA ribonucleic acid , which serves many purposes within the cell.
The secondary structure of DNA is a double helix, like two spiral staircases wrapped around each other. The double helix itself can bend and twist to form a helix as well. This helix of a helix is called a superhelix.
The process of forming a superhelix in DNA is known as supercoiling. Supercoiling of the double helix is a tertiary structure in DNA. Adapted from Wikimedia Commons.
Protein Biophysics Proteins are involved in nearly every biological process within the cell. Examples include catalyzing biochemical reactions, regulating turning on and off biochemical processes, and transporting molecules across cell membranes, from cell to cell and from one part of a cell to another. Proteins are also involved in cell motility self-induced movement of the cell. In order to carry out these functions, proteins typically must fold into very specific shapes, bind with other molecules, or undergo one or more conformational transitions.
Since proteins do all of these things as part of their normal function, understanding the physics of protein folding, conformational transitions, and binding is crucial to understanding and possibly controlling their role in biological processes.
Bioenergetics This branch of biophysics studies the physics of energy flow in living systems. Bioenergetics is concerned with all levels and branches of biophysics, from the environment, to the organism, to the cell, and to the molecules within the cell.
At the core of bioenergetics is the study of how organisms and cells obtain the energy they need to carry out biological processes. This includes where the energy comes from, how the energy is stored, how the energy is converted into various forms, and where and how excess or unusable energy is released. While every branch of biophysics needs to be concerned with energy, some biophysicists specialize in understanding the energetics of any biological process, 19 B i o p h y s i c s D e mys tifie d whether the process is protein folding, DNA unwinding, respiration, or energy flow in the environment.
Thermodynamics Very closely related to bioenergetics is the study of thermodynamics. The laws of thermodynamics describe how energy behaves in physical systems, biological or otherwise. The first law of thermodynamics states that energy cannot be created or destroyed. The second law of thermodynamics states that in a closed system the orderliness of the system can never increase, but can only decrease over time.
At first glance, because living things are so complex and highly organized and because they have the ability to stay organized, it would appear that living things may somehow violate the laws of thermodynamics, particularly the second law.
But living things are not closed systems. They interact with their environment. Yet as recently as the s many scientists continued to consider the possibility that living things do not behave according to the laws of physics, at least as we know them. The Physical Aspects of the Living Cell, he speculated that we may yet discover new laws of physics at work in living things that are not apparent in the inorganic world.
However, decades of exhaustive thermodynamic and physical studies of living things only confirm that organisms follow the same laws of physics found in the nonliving universe.
Statistical Mechanics Statistical mechanics is the application of probability and statistics to large populations of molecules. Although it is impossible to measure the exact energy or state of every one of the trillion billion molecules in a test tube or cell, it is possible to develop models of how those molecules behave mechanically. A model in our case is a mathematical description of how the molecules move, how much energy they have, how they change shape, and so on.
The model is then used to calculate the statistical probability of an event, for example, the probability of a protein molecule undergoing a shape change needed for its function.
Once the probabilities are known, they can be used to calculate statistical averages for the entire sample that is, for the entire population of molecules in the test tube or cell.
These statistical averages, in turn, can be associated with Chapter 2 B i o p h y s i c a l T o p i c s specific things that we can measure.
For example, the statistical averages can be used to calculate and predict thermodynamic quantities such as temperature, pressure, and amount of energy released or absorbed. In this way, even though it is impossible to directly measure what each and every molecule is doing, statistical mechanics allows us to interpret the things we can measure in terms of what specific molecules are doing. The interpretation is not direct knowledge, but we can design experiments so that the results either support or disprove our interpretation of what the molecules are doing.
This is an important point in biophysics and in science in general. Write a customer review. Read reviews that mention signals and systems math steps concepts demystified school. Top Reviews Most recent Top Reviews.
There was a problem filtering reviews right now. Please try again later. Paperback Verified download. Needless to say, signals and systems are very relevant to the topic, and if it's been a while since you've done anything with them and find yourself needing to re-smart yourself quick, this book is outstanding.
I managed to knock off the rust, and pull a few things together as well. The math is complete, but the author don't skip steps assuming you know why he did it. You came to be demystified, not told "there's a unifying point to prove here, and we'll leave that to you as an exercise.
This isn't as in-depth as books I've seen in the past more explicit textbooks , but if you're using this to get competent so you can do other things, it is simply outstanding.
If you've got a solid grasp of calculus it's not for dummies , then you can follow well enough to get the main point. Kindle Edition Verified download. As an older student going back to graduate school to learn signal and systems, I knew I was getting into trouble.
My biggest problem was just trying to get the Professors or TA's or anyone to walk me through some of the equations, so I could get a feel for the math. Like baby-steps pedantic steps, and for some reason trying to get anyone to do that was nigh impossible. But Signals and Systems Demystified did just that, all the way down to the steps of reminding you a basic calculus and algebra operations. Stuff, Professors and TAs might take for granted in class, but as an older student it was all I was missing.
To be walked through basic to medium problems to get a feel for the Math again. I admit I have only gone through the first part of the book, and I hope the rest is like that, but just getting those answers helped ease a lot of problems I have been having with the first few weeks of class. David McMahon has done a great thing by writing a book that takes you through the simplest of steps. Just for a frame of reference, I am an online electronic engineering student and I am nearing the end of multi-year journey towards my bachelors degree with a 3.
I was having problems in my digital signal processing class. I was looking for THE book to explain everything to me. This is not that book for me. In all fairness, I never did find THE book. DSP is a tough subject, you probably won't find a book to give you the "A-ha!
As with most DSP books, this one does great at explaining the concepts of the signal, but very poorly explaining the math behind it.
This book presents a good amount of material. It also has a good amount of solved problems for each section and usually explains what is going on. For the price I can't find anything wrong with it. I love the way the information is presented, in a smart and logical order.
Easy understanding. The way he teaches makes it less stressful and fun to read. I'd highly recommend this book. He also has several others that are just as good. I enjoy his technique!
Not much better than my text book. Does not cover convolution to a level that was useful.