ADS学习第五课ChannelSIm

ADS学习第五课ChannelSIm Agenda • Introduction to Channel Simulator in ADS 2009 Update1 – Bit-by-bit mode – Statistical mode • Channel Simulator hands on lab – Eye diagram simulation using Bit-by-Bit mode – Eye mask analysis – Statistical eye diagram and BER analysis Channel Simulator 2 PDF 文件使用 "pdfFactory Pro" 试用版本创建 Channel Simulator 3 Introduction to Serial Link Channel ∑ Jitter EQ RX Received Signal ∑ Jitter XTalk1 PRBS EQ ∑ Jitter XTalkN PRBS EQ ∑ Jitter TX PRBS EQ PDF 文件使用 "pdfFactory Pro" 试用版本创建 Challenges and Solutions with Serial Link Analysis Challenges • Low BER performance (10- 12 or less) used to imply long simulations • Issues with interconnect models • Multiple crosstalk channels • Jitter modeling for transmitter and receiver Solution: ADS Channel Simulator • New in ADS 2009: Bit-by-bit mode • New in ADS 2009 Update 1: Statistical mode Channel Simulator 4 PDF 文件使用 "pdfFactory Pro" 试用版本创建 Channel Simulator 5 Comparison of Techniques in ADS 2009 Update 1 Transient Simulator Channel Simulator: Bit-by-bit mode Channel Simulator: Statistical mode Method Modified nodal analysis of Kirchoff’s current laws for every time step Bit-by-bit superposition of step responses Statistical calculations based on step response Applicability Linear and non￾linear circuits LTI, any specific bit pattern, adaptive eq. taps, IBIS AMI LTI, fixed (general) bit pattern, fixed eq. taps BER floor in one minute simulation ~10-3 ~10-6 Arbitrarily low PDF 文件使用 "pdfFactory Pro" 试用版本创建 Channel Simulator: Bit-by-bit mode 1) SPICE-like transient response of single bit: runs on existing schematic 2) Response of millions of bits per minute using signal processing techniques Superposition ISI Channel Simulator 6 PDF 文件使用 "pdfFactory Pro" 试用版本创建 Channel Simulator: Statistical mode 1) SPICE-like transient response of single bit: runs on existing schematic 2) Statistical calculations including ISI, crosstalk, jitter specification, equalizers, and encoding Channel Simulator 7 PDF 文件使用 "pdfFactory Pro" 试用版本创建 Channel Simulator 8 Channel Simulator: Bit-by-bit and Statistical Modes Subst1 Dielectric-i : ER[i], H[i], TAND[i] Metal-i : T[i], COND[i], TYPE[i] M etal-2 M etal-1 Dielectric-1 TL2 TL1 blah blah_1 ModelType=MW Via2 Via1 S4P SNP1 4 1 2 3 Ref ML2CTL_V CLin1 EyeDiff_Probe EyeDiff V+ V- Integrate layout artwork into schematic PDF 文件使用 "pdfFactory Pro" 试用版本创建 Lab Exercise 1: Simulate PCI Express channel to determine eye diagram performance • Complete PCI Express channel topology by connecting source/load impedance, transmitter and eye probe • Configure behavioral transmitter model for PCI Express Gen 2 specs • Insert receive mask and check violations Channel Simulator 9 PDF 文件使用 "pdfFactory Pro" 试用版本创建 PCI Express Channel- Passive Interconnects Goal: To create and complete PCI Express channel for eye diagram simulation • On an ADS schematic page place a PCI Express Channel model using menu – DesignGuide à PCI Express à PCI Express Interconnect Models à Channel Model • Using tool bar icon Push into hierarchy of this channel to study various components and Pop out Channel Simulator 10 PDF 文件使用 "pdfFactory Pro" 试用版本创建 PCI Express Channel- Passive Interconnects • Select and connect differential source termination – DesignGuide à PCI Express à PCI Express Source/Load Terminations à Source Impedance – Connect Source impedance to input differential pin • Use function key f5 to move component text • Select and connect differential load termination – DesignGuide à PCI Express à PCI Express Source/Load Terminations à Load Impedance – Connect Load impedance to other three differential pins Channel Simulator 11 PDF 文件使用 "pdfFactory Pro" 试用版本创建 Channel Simulator 12 PCI Express Channel- Transmitter and Eye Probe Goal: Connect differential transmitter, modify it for PCI Express specs and connect eye diagram probe • Change Component Palette to Simulation – ChannelSim • Select TX_Diff component from Palette and connect it to the input differential pins • Edit TX_Diff component using mouse double click and define following parameters Ø PRBS > Bit rate : 5 Gbps Ø PRBS > Vhigh : 1.2 V Ø PRBS > Vlow : -1.2 V Ø PRBS > Rise/Fall : 30 psec Ø PRBS > Resister Length : 23 Ø Encoder > 8B10B : Enable Ø EQ> Specify De-emphasis : 3.5 dB PDF 文件使用 "pdfFactory Pro" 试用版本创建 PCI Express Channel- Transmitter and Eye Probe • Select EyeDiff_Probe from Palette and connect it to the output differential pins Channel Simulator 13 PDF 文件使用 "pdfFactory Pro" 试用版本创建 PCI Express Channel Simulation Goal: Simulate PCI Express channel for its eye diagram behavior • From Palette place Channel Simulation Controller (ChannelSim) on the schematic page • Edit Channel Simulation Controller using mouse double click and define number of bits as 50000 • Run simulation using tool bar icon • In the data display window, place a rectangular plot and add Density trace • Place List trace and add Height and Width measurements