- 2080 Bhadra · 4 marks
Band pass (400 rad/s, 150 rad/s) from 1 dB ladder
Short answer
Using LP→BP transformation s→(s²+ω₀²)/(Bs) with ω₀=400 rad/s, B=150 rad/s: series 1.2817 H becomes 8.545 mH series 731.5 µF; shunt 1.9093 F becomes 12.73 mF ∥ 491.0 µH; series 1.4126 H becomes 9.417 mH series 663.7 µF; shunt 1.0495 F becomes 6.997 mF ∥ 893.3 µH; 1 Ω terminations.
Following circuit is a low pass filter having αp = 1dB and ωp = 1 rad/s. Obtain a bandpass filter ω0 = 400 rad/sec and bandwidth of 150 rad/sec. [Figure: source V1, 1 Ω source resistor, series 1.2817 H, shunt 1.9093 F, series 1.4126 H, shunt 1.0495 F, 1 Ω load]
Use the low-pass to band-pass transformation with rad/s () and rad/s. The prototype has dB at rad/s, so the band-pass filter will have 1 dB ripple between band edges and rad/s.
Element rules:
- series → series and ;
- shunt → parallel and .
Given ladder: series 1.2817 H, shunt 1.9093 F, series 1.4126 H, shunt 1.0495 F, 1 Ω terminations.
Rs=1 [ Z1 ] [ Z3 ]
o-/\/\-[ ]--+-----[ ]--+------+---o
| | | | +
Vs [ Y2 ] [ Y4 ] RL=1 Vo
| | | | -
o--------------+-------------+------+---o
| Arm | Band-pass element |
|---|---|
| Z1 (series) | 8.5447 mH in series with 731.45 μF |
| Y2 (shunt) | 12.729 mF ∥ 491.02 μH |
| Z3 (series) | 9.4173 mH in series with 663.67 μF |
| Y4 (shunt) | 6.9967 mF ∥ 893.28 μH |
Each pair resonates at 400 rad/s (e.g. ). These values are for terminations. For practical values, magnitude-scale by (e.g. for 1 kΩ terminations): multiply every L by and divide every C by .
✓ Answer checked by Claude Sonnet 5.5
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