CMOS Programmable Gain Amplifier with Hybrid Gain Control Mechanisms
碩士 === 國立臺灣大學 === 電子工程學研究所 === 104 === Several gain control mechanisms for the design of programmable gain amplifier (PGA) are presented in this thesis. In ultrasound imaging receivers, an accurate decibel (dB)-linear PGA is required to convert the dynamic range of reflected signal into an acceptabl...
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| Format: | Others |
| Language: | en_US |
| Published: |
2015
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| Online Access: | http://ndltd.ncl.edu.tw/handle/23256554029288989257 |
| Summary: | 碩士 === 國立臺灣大學 === 電子工程學研究所 === 104 === Several gain control mechanisms for the design of programmable gain amplifier (PGA) are presented in this thesis. In ultrasound imaging receivers, an accurate decibel (dB)-linear PGA is required to convert the dynamic range of reflected signal into an acceptable range for the analog-to-digital converter (ADC). In order to obtain a wide dB-linear gain range and fine step resolution with small gain error, both exponential and exponential approximation functions are used in the proposed PGAs. Several variable gain amplifier architectures and exponential approximation functions are discussed and analyzed in this thesis. Two different PGA architectures are fabricated in 0.18-μm CMOS process for comparison, including an open-loop based and a closed-loop based architectures. The open-loop based PGA can achieve a low noise characteristic, while the closed-loop based PGA can provide a better linearity performance.
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