臺灣博碩士論文加值系統

隨著乙太網路的蓬勃發展，區域網路資料傳輸速率的要求已增加到每秒百億位元的需求，就光纖系統而言，每秒百億位元的資料傳輸速率在幾年前就已被提出並且實做，但為了成本的考量，現在希望能將百億位元的資料傳輸速率實現在一般雙絞銅線上。
在這篇論文之中，我利用CMOS製程實做了一個適用於百億位元乙太網路系統之類比前端電路，其中包含了一個零點漂移補償線路(BLW Cancellation Loop)、一個可程式增益放大器(PGA)、一個低通濾波器(LPF)以及一個增益放大器(Gain Amplifier)。零點漂移補償線路透過一個數位類比轉換器(DAC)將信號回授給接收信號以消去飄移信號。可程式增益放大器則是負責補償因通道長度不同而造成的不同的通道衰減。低通濾波器負責對外來串擾進行抑制。增益放大器則是負責將接收端增益放大到系統所需求的大小。此外，本次設計中還包含了一個頻率調整線路用來控制低通濾波器的頻率響應。
本晶片是由0.18μm 1P6M CMOS製程來實現，根據佈局後模擬，類比前端線路所能涵蓋的增益範圍從4.9dB到13.9dB，增益的增加量1.5dB，頻寬則為293MHz。晶片之面積為0.88 × 0.82mm２，在1.8伏特電壓下之總功率消耗為48mW。晶片經佈局後模擬加以驗證，量測考量及結果也都會呈現在本論文中。

Since the Internet expands rapidly, the data rate of the local area network reaches 10 Gb/s. The optical systems with the data rate of 10 Gb/s have been proposed and implemented a few years ago. However, for the cost point of view, it is desired to implement the system with data rate of 10 Gb/s on the copper twisted-pair.
In this thesis, an analog front-end circuit suitable for 10 GBASE-T Ethernet system has been designed and implemented using CMOS technology. The analog front-end circuit includes a baseline wander (BLW) cancellation loop, a programmable gain amplifier (PGA), a low-pass filter (LPF) and a gain amplifier. The baseline wander cancellation loop compensates the BLW by a feedback loop using a digital-to-analog converter (DAC). The programmable gain amplifier compensates the signal loss due to different channel length. The low-pass filter suppresses the alien crosstalk. The gain amplifier increases the overall gain of the entire analog front-end to satisfy the system requirement. Moreover, a frequency tuning loop which controls the frequency response of the low-pass filter is implemented in this design.
The chip is fabricated using 0.18μm 1P6M CMOS technology. According to the post-layout simulations, this AFE has gain range from 4.9dB to 13.9dB with 1.5dB gain step and 293MHz bandwidth. The chip area is 0.88 x 0.82 mm2. The power consumption is 48mW under 1.8 V supply voltage. The chip is designed and verified with post-layout simulations. Testing considerations and experimental results are also presented.

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Present Generation LAN System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 10Base-T. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.2 100Base-T. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1.3 1000Base-T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 10 Gigabit Ethernet on Copper Wire. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Overview of Thesis Topics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Backgrounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Environment of 10Gigabit Ethernet On Copper Wire . . . . . . . . . . . . . . . 5
2.2 Channel Impairments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1 Channel Loss. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.2 Echo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.3 Crosstalk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.4 Alien Crosstalk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3. Subsystems Characteristics and Specifications . . . . . . . . . . . . . . . . . . . . . . 11
3.1 Programmable Gain Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2 Low-pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3 Baseline Wander Cancellation.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4. Subsystems Circuits Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.1 Programmable Gain Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1.1 Linearization Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1.2 PGA Circuit Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.2 Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.2.1 Gm-C Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2.2 Filter Circuit Designs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4.2.3 Frequency Tuning Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.3 Output Gain Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.4 Baseline Wander Cancellation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.4.1 DAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
4.4.2 Summing Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.5 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.6 Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5. Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.1 Measurement of Receiver Front End . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.1.1 Testing Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
5.1.2 Measurement Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.1.3 Performance Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
6. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

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