# Differential Equation

Categories: Linear Equations

Assume that the resulting system is linear and time-invariant. x[n] O + r0n] D y[n] +1 3 -2 Figure P6. 5 (a) Find the direct form I realization of the difference equation. (b) Find the difference equation described by the direct form I realization. (c) Consider the intermediate signal r[n] in Figure P6. 5. (i) Find the relation between r[n] and y[n]. (ii) Find the relation between r[n] and x[n]. (iii) Using your answers to parts (i) and (ii), verify that the relation between y[n] and x[n] in the direct form II realization is the same as your answer to part (b).

Systems Represented by Differential and Difference Equations / Problems P6-3

P6. 6 Consider the following differential equation governing an LTI system. dx(t) dytt) dt + ay(t) = b di + cx(t) dt dt (P6. 6-1) (a) Draw the direct form I realization of eq.

Get quality help now Marrie pro writer Verified writer

Proficient in: Linear Equations    5 (204)

“ She followed all my directions. It was really easy to contact her and respond very fast as well. ”   +84 relevant experts are online

(P6. 6-1). (b) Draw the direct form II realization of eq. (P6. 6-1). Optional Problems P6. 7 Consider the block diagram in Figure P6. 7. The system is causal and is initially at rest. r [n] x [n] + D y [n] -4 Figure P6. 7 (a) Find the difference equation relating x[n] and y[n]. (b) For x[n] = [n], find r[n] for all n. (c) Find the system impulse response. P6. 8 Consider the system shown in Figure P6. 8. Find the differential equation relating x(t) and y(t). x(t) + r(t) + y t a Figure P6. 8 b Signals and Systems P6-4 P6.

Get to Know The Price Estimate For Your Paper
Topic
Number of pages
Email Invalid email

By clicking “Check Writers’ Offers”, you agree to our terms of service and privacy policy. We’ll occasionally send you promo and account related email

You won’t be charged yet!

9 Consider the following difference equation: y[n] – ly[n – 1] = x[n] (P6. 9-1) (P6. 9-2) with x[n] = K(cos gon)u[n] Assume that the solution y[n] consists of the sum of a particular solution y,[n] to eq. (P6. 9-1) for n 0 and a homogeneous solution yjn] satisfying the equation Yh[flI – 12Yhn – 1] =0. (a) If we assume that Yh[n] = Az”, what value must be chosen for zo? (b) If we assume that for n 0, y,[n] = B cos(Qon + 0), what are the values of B and 0? [Hint: It is convenient to view x[n] = Re{Kej”onu[n]} and y[n] = Re{Ye”onu[n]}, where Y is a complex number to be determined. P6. 10 Show that if r(t) satisfies the homogeneous differential equation m d=r(t) dt 0 and if s(t) is the response of an arbitrary LTI system H to the input r(t), then s(t) satisfies the same homogeneous differential equation. P6. 11 (a) Consider the homogeneous differential equation N dky) k~=0 dtk (P6. 11-1) k=ak Show that if so is a solution of the equation p(s) = E akss k=O N = 0, (P6. 11-2) then Aeso’ is a solution of eq. (P6. 11-1), where A is an arbitrary complex constant. (b) The polynomial p(s) in eq. (P6. 11-2) can be factored in terms of its roots S1, … ,S,. : p(s) = aN(S – SI)1P(S tiplicities.

Note that – S2)2 . . . (S – Sr)ar, where the si are the distinct solutions of eq. (P6. 11-2) and the a are their mul­ U+ 1 o2 + + Ur = N In general, if a, ;gt; 1, then not only is Ae”’ a solution of eq. (P6. 11-1) but so is Atiesi’ as long as j is an integer greater than or equal to zero and less than or Systems Represented by Differential and Difference Equations / Problems P6-5 equal to oa – 1. To illustrate this, show that if ao = 2, then Atesi is a solution of eq. (P6. 11-1). [Hint: Show that if s is an arbitrary complex number, then N ak dtk = Ap(s)te’ t + A estI Thus, the most general solution of eq. P6. 11-1) is p ci-1 ( i=1 j=0 Aesi , where the Ai, are arbitrary complex constants. (c) Solve the following homogeneous differential equation with the specified aux­ iliary conditions. d 2 y(t) 2 dt2 + 2 dy(t) + y(t) = 0, dt y(0) = 1, y'() = 1 MIT OpenCourseWare http://ocw. mit. edu Resource: Signals and Systems Professor Alan V. Oppenheim The following may not correspond to a particular course on MIT OpenCourseWare, but has been provided by the author as an individual learning resource. For information about citing these materials or our Terms of Use, visit: http://ocw. mit. edu/terms. 