自二戰時期人類發明雷達以來，雷達便逐漸在人們的生活中佔據重要的腳色，雖然一開始是以戰爭中搜索敵軍為目的而誕生，但隨著和平的到來雷達也漸漸走進人們的生活，不論是飛航安全、汽車防撞系統、天氣預報、天文研究、醫療照護等都用的到雷達，因此雷達對於人們生活的重要性自然是不言可喻。
在雷達系統中，由接收器及前端電路將訊號接收並且降頻之後，便交給類比基頻電路將訊號做進一步的放大，並消除製程變異及佈局誤差產生之直流偏移，放大過的訊號將經由濾波器濾除頻帶外雜訊之後交由類比數位轉換器處理，而前端電路降頻的部分可以分為直接取樣式及混頻器降頻式，由於直接取樣式的降頻方式降頻後的訊號即為直流訊號，因此基頻電路不使用濾波器而是使用積分器來將雜訊平均掉，而混頻器降頻式的雷達後端電路則需要中頻濾波器來濾波。
本論文提出一個用於直流訊號之類比基頻電路及一個用於中頻之後端電路，前者包含電壓緩衝器、可變增益放大器、斬波開關、積分器、以及直流偏差消除器，使用台積電65奈米製程設計，操作電壓為1伏特；後者包含電壓緩衝器、可變增益放大器、六階巴特沃茲低通濾波器、四階等化器、以及差動差分放大器，使用台積電65奈米製程設計，操作電壓為1.2伏特。

Since World War Ⅱ human created radar, radar became an important character in people's lives. Although radar is created for searching enemy in the beginning. But with the arrival of peace, radar fade in people's lives. By using radar, we can ensure flight safety, achieve collision avoidance system, do weather forecast, research astronomy, do healthcare and so on.
In the radar system, the analog baseband circuit will amplify the signal and remove the DC offset generated by layout variation and process variation after the signal is received by receptor and reduced signal frequency by frontend circuit. then amplified signal will be referred to the ADC to operate after the filter filters the out of band noise.
This thesis presents a analog baseband for DC signal and one back-end circuit for intermediate frequency signal. The former includes voltage buffers, a programmable gain amplifier, a chopper switch, an integrator, and DC offset cancellation and is implemented with TSMC 65nm process, operating voltage at 1 volt. The latter includes a voltage buffer, programmable gain amplifiers, a sixth-order Butterworth low pass filter, a fourth-order equalizer, and differential difference amplifier and is implemented with TSMC 65nm process, operating voltage at 1.2 volt.

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