Active Filters
• 0 Vote(s) - 0 Average
• 1
• 2
• 3
• 4
• 5
 seminar surveyer Active In SP Posts: 3,541 Joined: Sep 2010 12-10-2010, 10:53 AM Abstract A filter is a system that processes a signal in some desired fashion. A continuous-time signal or continuous signal of x(t) is a function of the continuous variable t. A continuous-time signal is often called an analog signal. A discrete-time signal or discrete signal x(kT) is defined only at discrete instances t=kT, where k is an integer and T is the uniform spacing or period between samples   active filters.ppt (Size: 816 KB / Downloads: 133)
 project girl Moderator Posts: 10,114 Joined: Nov 2012 10-11-2012, 10:49 AM Active Filter   Active Filter.ppt (Size: 798 KB / Downloads: 99) Passive Filters made up of passive components - resistors, capacitors and inductors no amplifying elements (- transistors, op-amps, etc) no signal gain 1st order - design is simple (just use standard equations to find resonant frequency of the circuit) 2nd order - complex equations require no power supplies not restricted by the bandwidth limitations of the op-amps can be used at very high frequencies can handle larger current or voltage levels than active devices buffer amplifiers might be required Passive elements : Inductor BIG PROBLEM! high accuracy (1% or 2%), small physical size, or large inductance values are required ?? standard values of inductors are not very closely spaced difficult to find an off-the-shelf inductor within 10 percent of any arbitrary value adjustable inductors are used tuning such inductors to the required values is time-consuming and expensive for larger quantities of filters inductors are often prohibitively expensive Active Filter no inductors made up of op-amps, resistors and capacitors provides virtually any arbitrary gain generally easier to design high input impedance prevents excessive loading of the driving source low output impedance prevents the filter from being affected by the load at high frequencies is limited by the gain-bandwidth of the op-amps easy to adjust over a wide frequency range without altering the desired response