Filters Flashcards
What is the definition of a filter?
A device or process that removes some unwanted components or features from a signal. It is designed to pass certain inputs that match a predetermined frequency while also blocking other inputs.
What are the various filter classes?
- Linear or Non Linear.
- Time invariant or time variant
- Casual or non Casual
- Analog or Digital
- Discrete time(sampled) or continuous time
- Passive or Active type
- Infinite impulse response(IIR) or Finite impulse response(FIR)
What is an Active Electronic Component?
They rely on a source of energy, and can usually inject power into a circuit. These components include transistors or vacuum tubes….
What is a Passive Electronic Component?
Passive Components can’t introduce net energy into a circuit and can’t rely on a source of power. As a consequence they can’t amplify the power of a signal but they can increase or decrease voltage or current. Components include two terminal components like resistors and capacitors, inductors and transformers.
What is an Active Filter?
An analog filter that is made out of active components like an amplifier.
What is a passive filter?
A filter that is made up entirely out of Passive components. The main difference between it and an active filter is that it can’t cause a power gain( add energy or control current)
What are the advantages of Active Filters?
Usually preferred to passive filters. They come in a compact form,
Have a very high input impedance to prevent excessive loading of a driving source.
Very low output impedance, so the load won’t effect the filter.
Usable with low signal levels as it is able to amplify.
Less affected by noise from electromechanical interference.
Generally easier to design.
What are the disadvantages of Active Filters?
They need an external power supply.
Op Amps have limited bandwidth so can’t be used at high frequencies. And they can also introduce internal noise and signal errors due to offset and bias signals.
Can’t handle as large current and voltage levels as Passive filters.
What are the main types of Filters?
Low-pass Filters
High-pass Filters
Band-pass Filters
Band-Stop Filters
What is a high pass Filter?
A filter that passes signals with a frequency higher than the cut off frequency and will reject signals that have a frequency lower than their predetermined value.
What is another name for a high pass filter?
Low cut
What is a Low pass Filter
A filter that will only pass signals that have a frequency lower than their set value. It is the compliment of a high pass filter.
What is another name for a Low Pass Filter?
High Cut
What is a band pass Filter?
A filter that will only let through signals that have a frequency within a set range. We can also create these filters out of low and high pass filters. An example of an analogue band pass is an RLC circuit.
What is a band stop Filter?
It will let all signals through apart from those within a set range. It is the opposite of a band pass filter and can also be created by combing high and low pass filters.
