Author Institution: Agilent TechnologiesSlides presented at the 5th Annual Photonic Doppler Velocimetry (PDV) Users Conference held at The Ohio State University, Columbus, Ohio, September 8-9, 2010

Asay, Brig

KnowledgeBank at OSU

Understanding how real time oscilloscopes  achieve > 16 GHz bandwidth Agilent Technologies 7000B Series  U1600A/B Series 6000 Series  5000 Series  NEW April 27 90000 Series  U2700 Series 1000 Series  Agilent Oscilloscope Portfolio Fastest growing oscilloscope manufacturer  DCA-J Sampling  90000 X-Series  9000 Series   Highest bandwidth and signal to noise ratio at 8 and 12 GHz   8 channels and only 7 rack U high   40 GSa/s across all eight channels   Up to 25mS of captured data (1 G memory)   PCIe download speeds of 80 Mb/s, including Fibre connector   Full Diskless Operation, Run Without Hard Drive  90000A 8 Channel Form Factor DSA-X 91604A DSA-X 92004A DSA-X 92504A DSA-X 92804A DSA-X 93204A Analog Bandwidth 16 GHz 20 GHz 25 GHz 28 GHz 32 GHz Max Sample Rate 80 GSa/s Max Memory 2 Gpt Probe Bandwidth Up to 30 GHz Introducing the Infiniium 90000 X-Series Oscilloscopes  The industry’s highest real-time measurement accuracy   The industry’s first 30 GHz oscilloscope probing system   The industry’s most comprehensive measurement software  Bandwidth upgradable scopes and probes Engineered for 32 GHz true analog bandwidth that delivers: Schedule 1. Brief de-embedding presentation  2. Scope Architecture 3. Hardware Performance 4. Frequency Interleaving 5. DSP Boosting 6. Measurement Comparisons 7. Conclusion A common system: Link Die Bonding wire/pins Pc transmission line Standard connector Pc transmission line Cable Standard connector Bonding wire/pins Die Life Cycle of a Transported sample… Starts in here Ends in here May 28th, 2009 Agilent Confidential Familiar Sight? Agilent Confidential 7 Bank Temperature sign Ambient Air2 ~102 Degrees F Temperature Sensor Ambient Air1 ~85 Degrees F Sun Thermocouple Factors:  Clouds, trees, wind, Sensor enclosure, time May 28th, 2009 Measurement Plane Agilent Confidential 8 Device Test Cables Standard Connector Test Access Fixture May 28th, 2009 Measuring Waveforms on a System Agilent Confidential 9 50Ω  What you want to Do… What you End up Having… M M T-linecable 0 length Realtime Oscilloscope= Waveform Analyzer 1 meter or more S 50W  Instrument Termination Waveform Analyzer Measurement  Plane Simulated Measurement  Plane May 28th, 2009 Digital Source Digital Source Simulating an Additional Channel Element Agilent Confidential 10 Standard Cable  Model S Realtime Oscilloscope= Waveform Analyzer 50W  Instrument Termination What you Want… What you Have… Simulated Measurement  Plane M T-linecable Realtime Oscilloscope= Waveform Analyzer 1 meter or more 50W  Instrument Termination May 28th, 2009 Digital Source Digital Source Virtual Probing (or Measurement Plane Relocation) Agilent Confidential 11 50Ω  M Waveform Analyzer S Connector  Fixture Cable Connector  Fixture Cable Realtime Oscilloscope= Waveform Analyzer 50W  Instrument Termination What you Want… What you Have… Measurement  Plane Simulated Measurement  Plane May 28th, 2009 Digital Source Digital Source Virtual Probing (or Measurement Plane Relocation) Agilent Confidential 12 What you Have… What you Want… M S Connector  Back Plane Connector Connector  Back Plane Connector High Z Probe May 28th, 2009 50Ω  Digital Receiver 50Ω  Digital Receiver Digital Source Digital Source ‘Simulated’ Measurements? Is it Unreasonable to consider that these scenarios can yield a new class of measurements where a waveform acquisition can be TRANSFORMED to a VIEW at another location either real or virtual??  NO!! It is NOT Unreasonable!  If we can describe the system accurately then it is „just math‟! Agilent Confidential 13 May 28th, 2009 Modeling your system Agilent Confidential 14 Circuit Elements: capacitors, inductors, resistors Parameters: Z, Y, S-Parameters Time Domain: Impulse Response Frequency Domain: Transfer Functions  A B C D Virtual Probing 50Ω  Source Device May 28th, 2009 Digital Source How a Source might be modeled: Agilent Confidential 15 Bond Wires CPad T-linepcb T-lineconnector KCoup1 KCoup2 CCon Z0 Z0 L L L L May 28th, 2009 Creating models in ADS (Agilent Design System) Agilent Confidential 16 May 28th, 2009 Stratix II FPGAS4P File forBoard/ConnectorS2P Filefor CableS-Parameters: Definition Agilent Confidential 17 S11 S21 S12 S22 a1 b1 b2 a2 22212122121111212221121121aSaSbaSaSbaaSSSSbb• A Matrix of S-Parameters is used to describe multi-port devices • a1,a2 represent the waves entering ports 1,2 respectively • b1,b2 represent the waves exiting ports 1,2 respectively • The voltage observed on port 1 is described by the vector addition     of the voltage waves described by a1,b1 • Frequency based (Sinusoids) kjjkabS Sjk ak bj Port 2 Port 1 Port 1 Port 2 May 28th, 2009 S-Parameters: Time Domain View Agilent Confidential 18 Device TDR Tx TDR Rx TDR Rx TDT: Time Domain          Transmission TDR: Time Domain           Reflection 1 2 Evaluate Wave Reflected at Port 1 vs Wave incident at Port 1…   S11  Evaluate Wave Transmitted through to Port 2 vs Wave incident at Port 1…   S21  Flip Device around and repeat for S22 and S12.  Digital Communication Analyzer   Agilent 86100C May 28th, 2009 S-Parameters: Frequency Domain View Agilent Confidential 19 Device 1 2 A C B D Vector Network Analyzer  Sinusoidal Stimulus Directional Devices Pick off  voltage waves  A, B, C, D •S21 = B/A  vector •S11 = C/A  vector •S12 = C/D  vector •S22 = B/D  vector   Agilent E5071C May 28th, 2009 S-Parameters: 2 to 4 Port  Agilent Confidential 20 1 3 2 4 2 Port 4 Port 1 2 1 Differential  Lane May 28th, 2009 S-Parameters: 4-Port S11 S21 S34 S22 a1 b1 b2 a2 S33 S12 S43 S44 a3 b3 b4 a4 S23 S32 S41 S14 S13 S31 S42 S24 4321432144434241343332312423222114131211aaaaSSSSSSSSSSSSSSSSbbbbMay 28th, 2009 Agilent Confidential Transfer Functions • A Transfer Function describes the ratio of a voltage wave   entering/exiting one port to a voltage wave exiting/entering    another port. • An S-Parameter or combination of S-Parameters can be used   as a Transfer Function. • Transfer Functions are commonly described in the frequency    domain H(s), where s=jw B 1 2 50Ω  M S If you want  to see signal at S but can only measure at M, what do you do? A 1 2 Device Measurement  Plane Simulated  Measurement  Plane May 28th, 2009 Agilent Confidential Digital Source Transfer Functions, continued B 1 2 50Ω  M S A 1 2 Device Measurement  Plane Simulated  Measurement  Plane VS M * H (s) =  S M(k) * H(n-k) = S(n) Acquisition Data Simulated Measurement Discrete Time Representation  of Transfer Function May 28th, 2009 Agilent Confidential Transfer Functions, continued B 1 2 50Ω  M S A 1 2 Device Measurement  Plane Simulated  Measurement  Plane VS An Ambiguity is what Relationship from M to S truly is: It could be: 1.  S= S21B-1  x M (Simple Gain Compensation) 2.  S = The node voltage, v(t), in the circuit   (Reference Plane Relocation) 3.  S = The node voltage, v(t), with Element B removed and 50W to ground connected (Channel Element Removal or De-Embedding)  v(t) May 28th, 2009 Agilent Confidential Schedule 1. Brief de-embedding presentation  2. Scope Architecture 3. Hardware Performance 4. Frequency Interleaving 5. DSP Boosting 6. Measurement Comparisons 7. Conclusion Maximum  Preamplifier Bandwidth Oscilloscope Bandwidth Spec DSP Boosting 16 GHz 20 GHz Frequency Interleave 16 GHz 30 GHz True Analog Bandwidth 32 GHz 32 GHz Scope Architecture Typical Scope Configuration Attenuator Pre-Amplifier Sampler Trigger Chip ADC Memory Controller Memory This presentation will focus on the pre-amplifier and the importance of understanding its bandwidth The oscilloscope pre-amplifier Agilent‟s proprietary multi-chip modules 1. Presents a DC coupled 50 ohm termination impedance at the scopes inputs to its full bandwidth 2. Provides a mean to offset the dynamic range of the input signal 3. Corrects the response of the oscilloscope 4. Provides anti-aliasing at maximum sample rate 5. Can drive both sampler IC and the trigger IC 6. Isolates the sampler IC from the trigger outputs Preamplifier output bandwidth determines the bandwidth of the oscilloscope Unless:  You DSP boost  You use frequency interleaving Hardware Performance (pre-amplifier BW)  Pre-Amplifier Sampler ADC ADC Sampler Requires significant investment to achieve raw hardware performance to bandwidths > 16 GHz  Semiconductor Process Cutoff Frequency (GHz) Agilent Indium Phosphide HBT 200 IBM 8HP 207 Infineon B7HF200 200 IBM 7HP 110 ST BiCMOS9MW 230 IHP SG25H1 190 Key Points of Hardware Performance  Requires investment in state of the art chip processes  Typically will have linear noise density to full bandwidth  No noise penalty due to DSP  Flat frequency response  Design is still a key part of the oscilloscope performance  Data from 90000 X-Series (Hardware Perf.) Magnitude Flatness +/-0.25dB Linear Noise Density to 32 GHz ENOB >5 to 30 GHz 90000 X-Series features: • 32 GHz pre-amplifier enabled by its InP front end • performance advantages of true analog bandwidth (low noise, jitter, flat response) What is Frequency Interleaving Attenuator Diplexer Down -  converter Preamplifier Preamplifier ADC ADC ADC ADC High frequency components that are greater than the pre-amplifier bandwidth DSP Channel Combiner Frequency Interleaving is an RF Technique that allows for faster time to market to achieve higher bandwidth How does frequency interleaving work? Attenuator Diplexer Down -  converter Preamplifier Preamplifier ADC ADC ADC ADC High frequency components that are greater than the pre-amplifier bandwidth DSP Channel Combiner 1 2 3 4 5 6 1. Signal enters an attenuator 2. Signal then enters a diplexer 3. Low frequency content goes through pre-amplifer 4. High frequency content is immediately down-converted 5. Down-converted HF content, goes through lower BW rated pre-amplifier 6. Signal is all put back together Key Points of Frequency Interleaving  Requires significant DSP processing  Enabled by high powered PC   Achieved through significant advances in RF design  Down-conversion is a key part of the acquisition  Signal is actually interleaved twice  Allows for faster bandwidths with less investment than hardware performance  Data from frequency interleaved oscilloscope Noise density has 8dB gain at the “mixer point” > 3dB magnitude loss Frequency interleaved scopes feature: • preamplifier bandwidth rated to ½ the bandwidth of the oscilloscope • first oscilloscope to reach >20 GHz Hardware performance vs. frequency interleaving Hardware performance has:  25% higher ENOB  ½ the noise floor  ½ the noise density  2-5x lower jitter meas. Floor  5x flatter frequency response DSP boosting (extending the bandwidth) Pre-Amplifier Sampler ADC ADC Sampler  Does not extend the bandwidth as much as frequency interleaving.  Does not require additional hardware to extend the bandwidth  Frequency extension achieved with filters Gain How DSP boosting works 1. Pre-amplifier bandwidth (red trace) does not achieve full bandwidth 2. Filter is applied that “boosts” the high frequency components of the oscilloscope (green trace) 3. Additional bandwidth is achieved, up to 25% bandwidth increase (blue trace) 4. Bit tradeoff of the signal is the noise increase and ENOB erosion of the 2nd harmonic  Filter and software work together to achiever higher bandwidth Key points of DSP boosting  Requires bandwidth boosting of high frequency components through DSP processing  Achieves up to 25% additional bandwidth without the addition of extra hardware  Trades off measurement accuracy for extra bandwidth as the noise density is significantly increased where boosting filter is applied Data from DSP boosted oscilloscope 2nd harmonic distortion caused by DSP boosting at 10 Ghz 3dB of variation in frequency response Notice the gain of the filter, is easily shown in the noise density plot Hardware performance vs. DSP boosting Hardware performance has:  Limited 2nd harmonic ENOB erosion   ½ the noise floor   no noise density spike   2-5x lower jitter meas. floor   3-4x flatter frequency response Noise density increase due to boosting DPO7000, DSA/DPO70000, and DSA/DPO70000B Series Digital Phosphor Oscilloscopes Specifications and Performance Verification Technical Reference”  Conclusion  Agilent‟s 90000 X-Series oscilloscope is the only oscilloscope with >16 GHz pre-amplifier bandwidth and as a result has the lowest noise floor, highest effective bits, and flattest frequency response  Frequency interleaving achieves the highest frequency gain, with the least pre-amplifier bandwidth, but trade-off is signal is down-converted and interleaved twice  DSP boosting achieves higher bandwidth with little additional hardware, but tradeoff is increased noise 

Understanding how real time oscilloscopes achieve > 16 GHz bandwidth

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Understanding how real time oscilloscopes achieve > 16 GHz bandwidth

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