The document outlines the syllabus for a unit on attenuators and filters, covering key concepts such as characteristic impedance, filter design, and types of filters including low pass, high pass, band pass, and band stop filters. It discusses the properties and applications of filters, defining important terms such as cut-off frequency and characteristic impedance. Additionally, it delves into the design of various filter types, including constant k and composite filters.

1. prepared by
D V S Ramanjaneyulu
Asst.professor
Ace engineering college
1
UNIT-5
ATTENUATORS &FILTERS

2. Syllabus ……
2
Characteristic impedance, image transfer
constants,.
Design of Attenuators, impedance
matching network.
T and π Conversion.
LC Networks and Filters: Properties of
LC Networks, Foster’s Reactance theorem.
design of constant K, LP, HP and BP
Filters, Composite filter design.
Problem solving.

3. 3

4. FILTERS
Definition : Filters are frequency selective networks that attenuate signals
at some frequency and allow others to pass with or with out attenuation
Properties of filters
A Filter is constructed from purely reactive elements
Ideally filters should produce no attenuation in the desired band called
pass band and should provide attenuation at all other frequencies called
attenuation band or stop band
The frequency which separates the pass band and he stop band is called cut-off
frequency.
Applications of filters

5. Classification of filters :
On basis of frequency characteristics filters are classified
in to four types
i. Low Pass
ii. High Pass
iii. Band Pass
iv. and stop
Low Pass Filter : A low pass filter allows all frequencies
up to a certain cut-off frequency to pass through it
and attenuates all the other frequencies above cut off
frequency
High Pass Filter : A high-pass filter attenuates all the
frequency below the cut- off frequency and allows all
other frequencies above the cut-off frequency
Band Pass Filter :A band-pass filter allows a limited band
of frequencies to pass through it attenuates all other
frequencies below or above the frequency band
Band stop Filter : A band-stop filter attenuates a limited
band of frequencies but allows all other frequencies
to pass through it

6. Characteristics of ideal filter

7. Characteristics of Practical
filter

8. CHARACTERISTICS IMPEDANCE OF T NETWORK
Definition : The value of load resistance at which power transfer is maximum and
hence network experiences minimum losses is called Characteristic Impedance

10. PROPAGATION CONSTANT(γ) OF T NETWORK
THE current leaving any section will be definite
proportion of that entering section and in general will
Be out of phase with it.

11. CHARACTERISTICS IMPEDANCE OF ∏ NETWORK