a k a lazy loading may yield better performance

Ngày tải lên: 08/08/2012, 17:20

... signals Signals, like materials, are real physical objects, but are intangible Humankind learned to adapt a mouth (originally developed for eating) and an ear (designed for hearing predators approach) ... computer, such as a desktop workstation, readily available and easily programmed Or it may be special purpose digital hardware designed specifically for the task at hand Intermediate between these ... this acoustic signal for later playback Digital forwarding and recording of speech have certain advantages, as we shall discuss later In order to use digital transfer and storage we require a method...

Ngày tải lên: 15/12/2013, 03:15

... we may accomplish this by multiplying each signal value separately We already know that multiplication of a signal by a real number can represent an amplification or an attenuation It can also ... that one can go back and forth between analog and digital signals A device that converts an analog signal into a digital one is aptly named an Analog to Digital converter or A/ D (pronounced A ... the fact that they are identically zero only for a constant A is a 38 SIGNALS linear operator since for any two signals II: and y, A@ + y) = AZ+ Ay and for any number c and signal 2, Acx = cAx As...

Ngày tải lên: 24/12/2013, 11:17

... to mathematics for a time, studying at the Ecole Normal in Paris under the greatest mathematicians of the era, Lagrange and Laplace After that school closed, he began teaching mathematics at the ... and phase representation Chief among them are the lack of symmetry between dk and pk and the lack of simple formulas for these coefficients In fact, the standard method to calculate dk and pk ... have proven that any signal of period T can be expanded in these signals, they are an orthonormal set of signals that span the space of periodic signals, and so an orthonormal basis The {vk} are...

Ngày tải lên: 24/12/2013, 11:17

... The FT, which maps analog signals to continuous spectra, and the DFT, which makes digital signals into discrete spectra, are The zT takes an arbitrary digital signal and returns a continuous function ... three main resonances at 500, 1820, and 2510 Hz and a weak fourth at a higher frequency is that if the frequencies not overlap the signals may be separated by appropriate filters Isolation in ... of a train of deltas is a single Dirac delta? No, because the same thing happens for all w of the form as well! So similarly to the Gaussian, a train of impulses has an FT of the same form as...

Ngày tải lên: 24/12/2013, 11:17

... most detailed information available as to individual signal values This implies that all single signal value statistics can be derived from it For a digital signal we can express the mean as a sum ... mean Also this estimator has a variance that decreases with increasing N as k That is, if we double the number of times we estimate the mean, the average variance will drop by half; the variance ... forms that we shall use in Chapter EXERCISES 5.6.1 Consider a stationary signal that can only take the values and What is the probability that the signal is nonzero at two times r apart? What is...

Ngày tải lên: 24/12/2013, 11:17

... can be written Aoxn +ArAs, where al = -Al and uo = A0 + Al What is the connection between the coefficients of acxn+arx,-1 +cQx~-~ and Aex,+AiAz, +A2 A2~,? What about aOx,+alx,-1 +a2 x,-2 +a3 xn-3 and ... be stable, stable causal systems are called realizable, meaning simply that they may be built in analog electronics Real-time digital systems can realize only stable streamable systems; the amount ... avoided at all costs; but milder divergences are not as damaging In any case true analog systems are always stable (since real power supplies can only generate voltages up to a certain level), and...

Ngày tải lên: 24/12/2013, 11:17

... time t At any particular spatial coordinate the wave is a signal, and at any particular time we see a three-dimensional spatially varying function A wave that travels at a constant velocity w ... the effective gain as a function of G 7.4.7 Simulate a system that has a causal MA filter in the feedback path Start with a low-pass filter, then a high-pass, and finally a band-pass Plot the frequency ... Dzn2)3h a symmetric MA filter So the numerical analysis apby parabolic approximation is equivalent to a particular which has only a single adjustable parameter, L task is the differentiation of a signal,...

Ngày tải lên: 24/12/2013, 11:17

... situated not far from a high-power radio transmitter Then one day a taxi cab passes by a rusty fence that can act as a nonlinear device, and the combination of the cab’s transmission and the radio ... the same complex exponential and pass filtered Demonstrate the equivalence of these two methods the practical advantages and disadvantages of each approach? 8.6 Phase-Locked signal can a complex ... replicating a previous value and skipping to catch up Although the corrupted value never explicitly appears, it leaves its mark as a phase shift that lasts for a short time interval What if there...

Ngày tải lên: 24/12/2013, 11:17

... linear predictability has been removed There is another way of looking at the residual signal Rather than taking no excitation and treating the residual as an error signal, we can pretend that ... we can show that cumulants are truly useful Assume that we have a non-Gaussian signal distorted by Gaussian noise Standard signal processing does not take advantage of the higherorder statistics ... way to sharpen a radar pulse’s autocorrelation Barker codes are often used because of their optimal autocorrelation properties, and the best way to embed a Barker code into a pulse is by changing...

Ngày tải lên: 24/12/2013, 11:17

... diagram only signal flow lines are indicated; invisible are the logic indications sent from the doubletalk detector to the adaptation mechanism and NLP, and the fact that the adaptation mechanism ... this artificially reconstructed signal as the reference This trick is known as Decision Directed Equalization (DDE) Using DDE makes adaptive equalization similar to adaptive noise cancellation and ... system varies too rapidly, even an adaptive algorithm may not be able to keep up The LMS algorithm is by far the most popular adaptive algorithm, and the Widrow-Hoff equation appears in many contexts,...

Ngày tải lên: 24/12/2013, 11:17

... (e.g., ‘book’ and ‘cook’ have different meanings), while and r are indistinguishable to speakers of many oriental languages, b and p are the same in Arabic, and various gutturals and clicks are not ... Bark (named after the acoustician H.G Barkhausen) scale approximates the natural frequency scale of the auditory system Psychophysically, signals heard simultaneously are perceived as separate ... functions, and various task geometries mapped onto brain geometries As early as 1861, Paul Broca described a patient who had lost his ability to speak although he did understand spoken language After...

Ngày tải lên: 21/01/2014, 17:20

... vertical rectangular arrays These vertical arrays are called racks; racks are made up of slots, and each slot can hold a single piece of equipment The piece of equipment in a specific rack and ... the city was annexed to the USSR and renamed Kaliningrad (Russian for ‘Kalinin’s city’) after the Soviet leader M.I Kalinin Today it is the capital of the Kaliningrad Oblast and is Russia’s sole ... shortened to RAX as an acronym for Really Awesome boxes RAX was a visual programming environment that simulated the operation of an analysis station Using a pointing device (originally a joystick, but...

Ngày tải lên: 21/01/2014, 17:20

... the available data Many of today’s DSP practitioners consider the FFT-based periodogram to be the most natural power spectral estimator Commercially available hardware and software digital spectrum ... BIBLIOGRAPHICAL NOTES Bibliographical Notes Kay and Marple have written a good tutorial of modern approaches to spectral analysis [128], and each has written a book as well [127, 1231 The periodogram ... This can be expressed as the combination of p previous values P Xn = c akxn -k k=l Substituting the definition and thus P c k= l ake-qik = (13.17) 518 SPECTRAL ANALYSIS we see that 1- akzvk k= l has...

Ngày tải lên: 21/01/2014, 17:20

... spectral points as there were time samples For general spectral analysis this may be taken as an advantage since we get higher spectral resolution, but some applications may require conservation ... means that on-theaverage enough computational resources are available In such cases double buffering can be used in the acquisition hardware, in order to compensate for peak MIPS demands Can hardware ... more accurate frequency estimates will be For block calculations one accumulates samples in an array, known as a buffer, and then processes this buffer as a single entity A technique known as double-buflering...

Ngày tải lên: 21/01/2014, 17:20

... we have the filter completely overlapping signal aA aAx0 Xl aAx2 al xx-1 a0 a- 1 xx xx+1 a- A+1 l ** X2X-l a- A x2x 52x+1 * *a DIGITAL FILTER IMPLEMENTATION 572 Likewise the last X outputs have ... What can be done if there are an even number of coefficients (half sample delay)? What are the advantages of such a implementation? What are the disadvantages? 15.3.4 Obtain a routine for factoring ... theorem of algebra (see Appendix A. 6) guarantees that all polynomials can be factored into linear factors (or linear and quadratic if we use only real arithmetic); so any filter can be decomposed...

Ngày tải lên: 21/01/2014, 17:20

... BIBLIOGRAPHICAL Bibliographical NOTES Notes The reader is referred to the mathematical handbook of Abramowitz and Stegun [l] for properties of functions, and polynomial and rational approximation ... quadratic approximation Knuth’s METRFONT typeface design program (which generates the fonts usually used with Tj$ and IX&$) is an example of a language that has @ as a primitive Its manual and entire ... its instantaneous phase $71= tan-l(yn, xn) - wn using one of the arctangent approximations and correcting for the four-quadrant arctangent How can you find w? Is the phase always accurately recovered?...

Ngày tải lên: 21/01/2014, 17:20

... self-modifying learning programs Slightly before the ENIAC, the Mark I computer was built by a Harvard team headed by Howard Aiken This machine was electromechanical and was programmed via paper tape, but ... once again, to use separate buses and memory banks These memory banks are called program memory and data memory respectively Standard computers use the same memory space for program code and data; ... zj and yk arrays in separate banks allows their simultaneous transfer to the appropriate registers The existence of more than one memory area for data is a radical departure from the memory architecture...

Ngày tải lên: 21/01/2014, 17:20

... takes an analog input signal and creates an analog communications signal is called a transmitter, while a receiver inputs an analog communications signal and attempts to recover, as accurately as ... original analog message signal A device that takes a digital input and creates a digital communications signal is usually called a modulator, while a demodulator inputs a digital communications ... signals back into digital data and convert the digital data back into the original message, respectively By using this model, rather than directly transmitting an analog signal over an analog channel...

Ngày tải lên: 21/01/2014, 17:20

... subbands the remaining ones are sorted in order of dynamic range and available bits awarded accordingly Subbands with relatively constant signals can be replaced by scalar-quantized averages, ... are particularly difficult in this regard All this said, there are many pitch tracking algorithms available One major class of algorithms is based on finding peaks in the empirical autocorrelation ... and a manually manipulated resonance chamber Unfortunately, the machine was not taken seriously after von Kempelen’s earlier invention of a chess-playing machine had been exposed as concealing a...

Ngày tải lên: 21/01/2014, 17:20