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1、第10單元 帶通與帶拒濾波器之設(shè)計與製作,帶通與帶拒濾波器之設(shè)計與製作,Band Pass Filter Design,Transformation form Low Pass to Band Pass,,Frequency,Elements Transformation form Low Pass to Band Pass,Band Pass Filter Design,Shunt Element becomes Parallel-Resonant Series Element becomes Series-Resonant,,BPF Frequency and Impedance Scal

2、ing,For Parallel-Resonant Branches:,For Series-Resonant Branches:,Where,R=The Final Load Impedance B=3-dB Bandwidth fo=The Center Frequency Ln=normalized Inductor Cn=normalized Capacitor,Summary of the Bandpass Filter Design Procedure,1. Transfer the Bandpass requirements into equivalent low-pass r

3、equirements. 2. Refer to the low-pass attenuation curves provided in order to find a response that meets the requirements of step1. 3. Find the corresponding low-pass prototype and write it down. 4. Transform the low-pass network into a bandpass configuration. 5. Scale the bandpass configuration in

4、 both impedance and frequency.,BPF Design Example,Ex. Design a BPF with the following requirement,fo = 75 MHz BW3 dB = 7 MHz BW45 dB = 35 MHz,Passband Ripple = 1 dB RS = 50 ohms RL = 100 ohms,Sol:,參考13-22頁之右圖可知，n = 3時之Chebyshev 可滿足設(shè)計之需求。,參考相關(guān)書本可得低通濾波器之雛形電路圖。,將前面所得之低通濾波器之雛形電路圖轉(zhuǎn)成帶通濾波器之 雛形電路。,,Low-Pass

5、 Prototype,Band-Pass Prototype,參考14-4頁可得,二階帶通濾波器 帶通濾波器可由低通與高通濾波器串連而成,,簡易二階 RLC 被動帶通濾波器,Band Rejection Filter Design,Design approach similar to band pass filter,Transformation form Low Pass to Band Rejection,Shunt Element becomes Shunt Series-Resonant Circuits Series Element becomes Series Parallel-R

6、esonant Circuit,,BRF Frequency and Impedance Scaling,For Series-Resonant Branches:,For Parallel-Resonant Branches:,Where,R = The Final Load Impedance B = 3-dB Bandwidth fo = The Center Frequency Ln = normalized Inductor Cn = normalized Capacitor,70 MHz 帶通濾波器,帶通濾波器之頻率響應(yīng)量測結(jié)果,帶通濾波器之輸出入返回?fù)p耗量測結(jié)果,帶通濾波器之介入耗損量測結(jié)果,900 MHz 帶拒濾波器,帶拒濾波器之頻率響應(yīng)量測結(jié)果,帶拒濾波器之輸出入返回?fù)p耗量測結(jié)果,帶拒濾波器之介入耗損量測結(jié)果,濾波器類型之比較,Character,Type,