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ELEC 412 RF & Microwave Engineering. Fall 2004 Lecture 12 Low and High Pass Filter Examples. Low-Pass Filter Design Example. Design a Low-Pass Filter with cut-off frequency of 900 MHz and a stop band attenuation of 18 dB @1.8 GHz.
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ELEC 412 RF & Microwave Engineering Fall 2004 Lecture 12 Low and High Pass Filter Examples Low and High-Pass Filter Examples
Low-Pass Filter Design Example • Design a Low-Pass Filter with cut-off frequency of 900 MHz and a stop band attenuation of 18 dB @1.8 GHz. • From the Butterworth Nomograph, Amax = 1 and Amin = 18. Amax = 1 since unity gain. And the order of the filter is N = 3. • From Butterworth Tables, g1 = g3=1.0 and g2 = 2. Low and High-Pass Filter Examples
Transformation From Low-Pass Filter Low and High-Pass Filter Examples
Normalized Lumped Parameter values • What to do with the gk ‘s and Where fc is the cutoff frequency and Lk_norm and Ck_norm are normalized element values Low and High-Pass Filter Examples
P5.7 Low-Pass Filter Design The normalized lumped element values: g0=1; g1=0.7654/(2fc ); g2=1.8478/(2fc ); g3=1.8478/(2fc ); g4=0.7654/(2fc ); g5=1.; Low and High-Pass Filter Examples
Denormalized Lumped Parameter Values and For all filter configurations Low and High-Pass Filter Examples
Low-Pass Filter Design Example Low and High-Pass Filter Examples
Low- To High-Pass Transformation • Transform the Low-Pass Filter Normalized Component Values to the Normalized High-Pass Values • Inductors in Low-Pass Configuration Become Capacitors in High-Pass. • Capacitors in Low-Pass Configuration Become Inductors in High-Pass Low and High-Pass Filter Examples
Denormalized Lumped Parameter Values and Same as that for the Low-Pass Filter Low and High-Pass Filter Examples
De-Normalizing Filter Component Values • All Normalized Component Values Are De-Normalized Using the Following: and Low and High-Pass Filter Examples