61 from Ch 13 Filters

61 from Ch 13 Filters - Making sense of EE / 2nd ed Filters...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
H = V output V input depends on the frequency. Frequency-dependent impedances belong to capacitors and inductors thus filters involve L and C. Quite often, filters are designed to suppress the noise and/or tune into the desired signal (your cell phone tunes into the better channel automatically; for your TV or radio you choose the channel yourself). Even more often, you may find that your circuit works as a filter though you did not want it to! Recall that any circuit has inductance & capacitance! Under sinusoidal steady-state conditions, in circuits with linear elements and sinusoidal input signals, we apply phasors to calculate voltages and currents. Thus phasors are used for analysis of filters. In the language of phasors, the input and output voltages are complex, thus the transfer function is complex; most often, we are interested in its magnitude H ( " ) . Using H ( ) at the very low and very high frequencies, we classify filters into 4 types: Low-Pass, High-Pass, Band-Pass, and Band-Reject (also called Band-Stop or Notch). Here we consider passive filters that act as voltage dividers built of R , L , and C , and active filters based on Op Amps (inverting amplifiers). Passive filters do not have energy sources, while active filters do: recall that Op Amps cannot work without power supplies. The cutoff frequency is the borderline between the Pass-Band and the Stop-Band of a filter. According to the convention that we use, the power of output signal at the cutoff frequency equals 50% of the maximal output power with the same load. Page 1 of 32
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/06/2010 for the course EECS 314 taught by Professor Ganago during the Spring '07 term at University of Michigan.

Page1 / 12

61 from Ch 13 Filters - Making sense of EE / 2nd ed Filters...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online