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barcode reading in asp.net CLAMPING in Software
CLAMPING Code 128 Code Set A Reader In None Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications. Code 128 Code Set A Printer In None Using Barcode generator for Software Control to generate, create Code 128B image in Software applications. The continuous functionf(t) is said to be clamped to produce the function fc(t) as shown in Fig. 22.3. The period of sampling is T and the frequency is ws = 2dT radians/time. The clamping can be described mathematically by the combination of impulse modulation and the application of a zeroorder hold as will soon be shown. Code 128 Code Set C Decoder In None Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications. Code 128 Code Set A Printer In Visual C#.NET Using Barcode generator for .NET Control to generate, create Code 128 image in .NET framework applications. T 2T 3T 4T 5T
Code128 Drawer In .NET Using Barcode generator for ASP.NET Control to generate, create Code 128 Code Set A image in ASP.NET applications. Code 128B Generator In .NET Using Barcode maker for .NET framework Control to generate, create ANSI/AIM Code 128 image in .NET applications. FIGURE 223 Clamping.
Encoding Code 128 Code Set A In VB.NET Using Barcode drawer for .NET framework Control to generate, create Code 128B image in VS .NET applications. Barcode Encoder In None Using Barcode generator for Software Control to generate, create barcode image in Software applications. SAMPLEDDATACONTROLSYSTEMS
UPCA Supplement 5 Printer In None Using Barcode generator for Software Control to generate, create UPCA Supplement 5 image in Software applications. EAN 13 Maker In None Using Barcode maker for Software Control to generate, create GS1  13 image in Software applications. FIGURE 224 Impulse modulation.
EAN / UCC  14 Generator In None Using Barcode maker for Software Control to generate, create GS1128 image in Software applications. Encode Code 39 Extended In None Using Barcode creator for Software Control to generate, create USS Code 39 image in Software applications. Impulse Modulation
Making C 2 Of 5 In None Using Barcode creation for Software Control to generate, create Industrial 2 of 5 image in Software applications. Bar Code Printer In Visual C#.NET Using Barcode printer for .NET Control to generate, create bar code image in VS .NET applications. As shown in Fig. 22.4, an impulsemodulated function consists of a sequence of impulse functions, the magnitudes of which equal the values of the continuous function at sampling instants. The impulsemodulated function is given the symbol f*(t). A convenient symbol for the impulse modulation sampler is shown as a switch (J ), which closes momentarily every T sec. It should be noted that the impulse modulation switch is purely symbolic, for there is no switch of this type present in the hardware used in sampling signals. Printing Code128 In VB.NET Using Barcode creator for VS .NET Control to generate, create Code 128 Code Set B image in VS .NET applications. Code 128A Printer In Visual C# Using Barcode printer for VS .NET Control to generate, create Code128 image in Visual Studio .NET applications. Zeroorder Hold
Decoding UPC  13 In VB.NET Using Barcode reader for .NET Control to read, scan read, scan image in VS .NET applications. UPC  13 Maker In None Using Barcode generator for Font Control to generate, create GS1  13 image in Font applications. The zeroorder hold is defined by the transfer function 1  eTs G/t,&) = s
Print ECC200 In None Using Barcode creation for Font Control to generate, create Data Matrix ECC200 image in Font applications. Linear 1D Barcode Generator In Java Using Barcode creator for Java Control to generate, create Linear image in Java applications. (22.1) Combining impulse modulation with the zeroorder hold, as shown in Fig. 22.5, provides the clamping. To illustrate how the zeroorder hold shapes the sequence of impulses into a clamped signal, a block diagram of the hold is shown in Fig. 22.6 in which an integrator and a transport lag are connected to implement the zeroorder hold. The operation of a zeroorder hold can be understood by expressing F,(s) as follows (see Fig. 22.5): Fc(s) = F+(s)1  eTs F*(s)eTs _ F*(s) s S s
(22.2) where F*(s) is the Laplace transform of the impulsemodulated function, f*(t). This expression shows that the clamped function fc(t) is obtained by a combination of integration, transport lag, and subtraction. Recall that integration in Eq. (22.2) is represented by l/s and transport lag by emTs. To understand the signals at the output of the integrator, one must recall that the integration of an impulse f(t) F(s) f*(t) F*(s) 1 @ fc(t) F,(s) F(z) FIGURE 225 Clamping.
SAMPLING
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f(c) 2T 3T 4T
T2T3T
FIGURE 226 Construction of a clamped signal.
function is a step function. The impulse occurring at t = 0 results in a pulse* of width T. (See Fig. 22.6.) The impulse occurring at t = T results in a pulse of width T starting at t = T. The remaining impulses each contribute a pulse of width T starting at successive values of T. The height of each pulse equals the magnitude of the impulse that produced it. The combination of these pulse functions provide the stairstep function associated with clamping. This rather mechanical description of clamping through implementation of the zeroorder hold transfer function may give the reader an intuitive feel for the abstract mathematical expression involved. LAPLACE TRANSFORM OF THE IMPULSEMODULATED FUNCTION
Let i(t) be a sequence, or train, of unit impulses that are separated by period T. This may be expressed as follows: co i(t) = s(t) + @t  T) + s(t  2T) + ... = c i (t  nT) n=O (22.3) The starred function f*(t) may be written as the product of f(t) and i(t): f*(t) = fW(t) Introducing the expression for i(t) from EQ. (22.3) into this equation gives f*(t) = f(t) g*(t  nT) n=O (22.4) *The pulse occurs because the integration of the impulse at I = 0 is combined with the integration of a delayed impulse of the same magnitude, but opposite sign, at t = 2 . SAMPLEDDATA
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Since i(t) has a nonzero value only at sampling instants (t = nT), f(t) may be replaced by f(nT) and then placed within the summation to produce the result f*(t) = &T)s(r n=O  nT) (22.5) Applying the Laplace transform of a unit. impulse, which is unity, and applying the theorem on translation of a function (See Chap. 4) to this expression for f*(t) give the Laplace transform of the impulsemodulated function: F*(s) = LCf*(t)} = &T)e T n=O
(22.6) The function F*(s) is referred to as the starred transform of f(t). An alternate form for F*(s) which is useful in proofs and derivations is given in the appendix of this chapter. This alternate form is based on the Fourier series representation of a periodic function.

