# Search results

1. ### How to get (frequency response) from this [difference equation]?

Homework Statement Given this difference equation y(k) (of a bandpass FIR filter) ... y(k) = \frac{1}{K^2} \sum_{m = k-K+1}^k \; \sum_{n = m-K+1}^m x(n) - \frac{1}{L^2} \sum_{m = k-L+1}^k \; \sum_{n = m-L+1}^m x(n) ... how does one derive this frequency response H(f)? H(f) = \frac{1}{K^2}...
2. ### Z-transform of conjugated sequence ( a straightforward exercise)

Z-transform of a conjugated sequence ("a straightforward" exercise) Homework Statement The conjugation property is expressed as x^*[n] \stackrel{Z}{\leftrightarrow} X^*(z^*) This property follows in a straightforward maner from the definition of the z-transform, the details of which are left...
3. ### Audio/Video DIY headphone wiring (nylon-stranded wire)

I've connected the 3 wires as shown in the picture: GROUND, GREEN, and RED (the latter 2 having their enamel removed). [PLAIN]http://img821.imageshack.us/img821/4133/nylonstranded.jpg [Broken] But I'm getting only low-volume (un-amplified) sound. Now, if I connect either GREEN or RED wire to...
4. ### Heating oil: effective or real output/yield (per liter)

Heating oil: effective or "real" output/yield (per liter) http://en.wikipedia.org/wiki/Heating_oil" [Broken] says that which is about 11 kWh/L. I was given an unbiased (but not necessarily correct) number that the effective output is about 8 kWh/L ... ... and a potentially biased number...
5. ### Show that power supplied = power dissipated

Show that "power supplied" = "power dissipated" Homework Statement For the circuit of Fig. 3-42, show that the power supplied by the sources is equal to the power dissipated in the resistors. Ans. P_T=940.3\text{ }W [PLAIN]http://img269.imageshack.us/img269/2010/dsc01005kn.jpg [Broken]...
6. ### Find (practical) current source constants, I and R

Homework Statement A practical current source has a current of 22 A. Loading the source with 50 \Omega results in terminal voltage of 390.3 V. Obtain the source constants, I and R. Homework Equations V=I\times R The Attempt at a Solution In my clumsy picture below, shouldn't I_{load} be...
7. ### Given I, find V across the elements (resistor, inductor, and capacitor)

Homework Statement The current after t=0 in a single circuit element is as shown in Fig. 2-37. Find the voltage across the element at t=6.5\mu s, if the element is (a) 10 k\Omega, (b) 15 mH, (c) 0.3 nF with Q(0)=0. Ans. (a) 25 V; (b) -75 V; (c) 81.3 V...
8. ### Given capacitance & energy dissipated, find the charge Q

Homework Statement A capacitance of 2\mu F having a charge Q_0 is switched into a series circuit of 10\Omega resistance. Find Q_0 if the total energy dissipated in the resistance is 3.60 mJ. Ans. 120 \mu C Homework Equations Q=CV The Attempt at a Solution E=\int_0^\infty...
9. ### Capacitance: given V waveform, find max. power

Homework Statement A capacitance of 60 \mu F has the voltage waveform shown in Fig. 2-36. Find P_{max}. [PLAIN]http://img828.imageshack.us/img828/5255/unled2copy.jpg [Broken] Homework Equations p(t)=i(t)u(t)=\left(C\frac{du(t)}{dt}\right)u(t) The Attempt at a Solution When is power at...
10. ### Inductance: given V waveform, find I

Homework Statement An inductance of 3 mH has the following voltage waveform: for 0<t<2\text{ }ms, v=15\text{ }V; for 2ms<t<4ms, v=0; and for 4\text{ }ms<t<6\text{ }ms, v=-30\text{ }V. Assuming i(0)=0, find the current at time (a) 1 ms, (b) 4 ms, (c) 5 ms. Ans. (a) 5 A; (b) 10 A; (c) 0...
11. ### Find max. stored energy (in capacitance and inductance)

Find "max. stored energy" (in capacitance and inductance) 1.) I'll start with capacitance since I get closer to solution (than in inductance problem). :redface: First get the voltage v(t)=\frac{1}{C}\int i(t)dt=\frac{1}{C}\int \frac{V_m}{R}e^{-\frac{t}{RC}}=-V_m e^{-\frac{t}{RC}} Now...
12. ### Rotating cylinder

Homework Statement Cylinder with mass of 2 kg can be rotated around fixed horizontal geometrical axis. Around cylinder's circumference there is wounded rope, end of which is pulled by force equal 2,5 N in a horizontal direction, so that cylinder's rotation is accelerated. In what time does end...
13. ### Simplify: (a+2b+3c, 4a+5b+6c, 7a+8b+9c)

Homework Statement "Simplify: (a+2b+3c, 4a+5b+6c, 7a+8b+9c)." All of these are vectors (a=\vec{a}, etc.) Homework Equations I know that set of vectors \vec{x}_1+\cdots+\vec{x}_n \in V is linearly independent if linear combination \alpha_1\vec{x}_1+\cdots+\alpha_n\vec{x}_n equals \vec{0}...