RF Measurements You Didn't Know Your Oscilloscope Could Make - Informa

RF Measurements You Didn't Know Your Oscilloscope Could Make January 21, 2015 Brad Frieden Product Manager Keysight Technologies

Agenda – RF Measurements using an oscilloscope (30 min) When to use an Oscilloscope vs Spectrum Analyzer? What RF measurement capability exists on your scope? (FFT) Advances in scope-based FFTs (annotation, gating, multiple FFT) Using Functions for Additional RF analysis Determining how good of RF measurements your scope will make (RF characterization – all scopes are not created equal) – Complimenting the Scope with Additional RF analysis software (15 min) Wideband EVM measurements, & modulation examples Using your scope to make RF measurements Page 2

Why is this so important? – Increase your debug and validation efficiency through oscilloscope frequency domain views Where is that noise coming from in the power distribution system? Quick, convenient view of expected DUT spectral content – May be one of the few ways to perform validation analysis of wideband RF signals – Practical understanding of the limits of test with new oscilloscope technology help you choose the right tools to complete validation – Learn techniques and tools to allow long target capture time, necessary to evaluate prototypes Why is this so important? What valuable thing will you take away/learn that will save you time/money or improve productivity Using your scope to make RF measurements Page 3

0 MHz BW PXA UXA 160 MHz 510 MHz 160 MHz BW 510 MHz BW 8 GHz BW 13 GHz BW Z Series S-Series Oscilloscope 1 90000-X Series 90000A Series # Channels Up to 4 The challenge of signal spectral bandwidth and number of channels needed 32 GHz BW 63 GHz BW RF Signal Spectral Bandwidth Using your scope to make RF measurements Page 4

Product Strengths For RF measurements – Spectrum / signal analyzers – Oscilloscopes In-band measurements In-band measurements Out of band measurements Widest analysis bandwidth Automated RF measurements More than one channel Best dynamic range Segmented memory to maximize target capture time Fast throughput with narrow Resolution Bandwidth Also offers sophisticated time domain analysis tools Using your scope to make RF measurements Page 5

Oscilloscope Functions Advanced Math - Every modern scope includes a variety of math functions - Math functions can: Help you view waveforms in unique and meaningful ways Can be a huge debug/test productivity boost Included are FFTs - # of functions vary by oscilloscope - Some scopes allow Matlab .m import for more complex functions Measurements - Fundamental to scope usage. - Can be made on FFTs and other functions Using your scope to make RF measurements Page 6

Frequency Domain Function Examples Clock signal & harmonics Coupling from unexpected sources Wideband FFTs Using your scope to make RF measurements Page 7

More Memory with Fixed Sample Rate Better RBW Tradeoff processing speed 20Kpts RBW 1.5 MHz 1 Mpts RBW 7.5 kHz Using your scope to make RF measurements Page 8

Live: 1 GHz sine input example Using your scope to make RF measurements Page 9

Hot application today is power integrity Power distribution noise translates into various clock jitter New Power Rail probe, 2 GHz BW, 50k ohm, 1:1, /- 24V offset Can apply offset to allow a close zoom onto the power noise The FFT can yield very important clues for noise sources Customizable in Footer Page 10

Live: Power supply noise measurement example Using your scope to make RF measurements Page 11

10 GHz coupled clock seen in the FFT view Then can trigger on that clock, average out all other noise Power rail Time gate zoom 10 GHz clock Time gate zoom on clock 10 GHz coupled clock seen amidst power supply switching noise Customizable in Footer Page 12

Live: wideband pulse RF measurements Using your scope to make RF measurements Page 13

Use Functions for Advance RF Measurements – 1 GHz Wide Chirp Example using 5 scope functions Example: 1 usec wide RF pulses, linear FM 3.5 GHz to 4.5 GHz, 10 usec PRI “Meas Trend” of Clock TIE to see inverse of phase shift Time view of single RF pulse in pulse train “Meas Trend” of Frequency to see frequency shift across the RF pulse (1 GHz linear shift) FFT of an RF pulse (variety of FFT window options) Using your scope to make RF measurements Page 14

Multiple FFTs – Multiple gates – Multiple FFTs on same waveform with different Start/Stops – FFT per input channel Using your scope to make RF measurements Page 15

Live demo: Gated FFTs Time gate of 80 us Using your scope to make RF measurements Page 16

Gated FFTs for Time/Frequency Correlation Using your scope to make RF measurements Page 17

How Good of RF Measurements Will Your Scope Make? – Not all scopes are created equally – Scope datasheet typically doesn’t include RF characterization – Scopes with better signal integrity technology blocks (low-noise front end, correction filters, higher ENOB) will have higher quality RF measurements – Find out Do a conversion from time-based specs Ask scope manufacturer for this info Using your scope to make RF measurements Page 18

Keysight Characterization Example TOI & EVM MSO-S 804A Third Order Intercept (TOI) Power of one tone (0 dBm) ½ Delta marker 0 22.5 dB 22.5 dB PSG Signal Generator MSOS804A EVM W-LAN 2.4 GHz 20 MHz wide 0.47% EVM rms PSG Signal Generator VSA Using your scope to make RF measurements Page 19

Oscilloscope Improvements over 1 Generation Amplitude and phase flatness Amplitude 1 dB/div Amplitude 1 dB/div Phase 20 deg/div 0 Hz 4 GHz BW 9000 Series --- no acquisition correction 10 GHz Phase 20 deg/div 0 Hz 10 GHz 8 GHz BW S-Series --- using acquisition correction Page 20

Oscilloscope Improvements over 1 Generation Phase Noise Example DSO9000 -106 dB/Hz S Series -120 dBm/Hz Using your scope to make RF measurements Page 21

Example: Getting Noise Density from Vrms Noise From S-Series Data Sheet 50 mV/div and 8 GHz BW http://www.coretechgroup.com/dBm Calculator.php V/div dBm Ref Level dBm/Hz Noise 1mV/div -28 dBm -158 dBm/Hz ** 2mV/div -28 dBm -158 dBm/Hz 5mV/div -24 dBm -156 dBm/Hz 10mV/div -18 dBm -154 dBm/Hz 20mV/div -12 dBm -150 dBm/Hz 50mV/div -4 dBm -143 dBm/Hz 100mV/div 2 dBm -136 dBm/Hz 200mV/div 6 dBm -130 dBm/Hz 500mV/div 16 dBm -124 dBm/Hz 1V/div 22 dBm -118 dBm/Hz 1.4mV rms noise -44dBm @ 8GHz -44dBm – 10log(8E09) -143dBm/Hz noise density Using your scope to make RF measurements Page 22

Ask Your Oscilloscope Manufacturer Keysight Infiniium S-Series example Using your scope to make RF measurements Page 23

Agenda – RF Measurements using an oscilloscope (30 min) When to use an Oscilloscope vs Spectrum Analyzer? What RF measurement capability exists on your scope? (FFT) Advances in scope-based FFTs (annotation, gating, multiple FFT) Using Functions for Additional RF analysis Determining how good of RF measurements your scope will make (RF characterization – all scopes are not created equal) – Complimenting the Scope with Additional RF analysis software (15 min) Wideband EVM measurements, & modulation examples Using your scope to make RF measurements Page 24

Additional Analysis VSA (Vector Signal Analysis) App can run on the scope, or on a PC Additional analysis Spectrum math EVM Channel power PSD ACP OBW Constellation diagrams Using your scope to make RF measurements Page 25

Demo of VSA with Scope --- 16QAM demod 3 GHz wide Using your scope to make RF measurements Page 26

Wideband QAM16 Example 3 GHz carrier, 1 GHz wide modulation QAM16 signal Measure of: Constellation diagram Time domain signal Spectrum EVM 0.58% Using your scope to make RF measurements Page 27

Demo of Chirp Radar analysis --- 2 GHz wide 2 GHz linear FM chirp Measure of: Spectral content Pulse “Real” Frequency across pulse Unwrapped phase across pulse Using your scope to make RF measurements Page 28

Demo of VSA 19 pulse option BHQ Use segmented memory in scopes for long captures Up to 64k segments Full suite of RF pulse measurements Statistical analysis Using your scope to make RF measurements Page 29

What have we seen? Scopes for RF measurements – New scopes make great, wideband RF receivers, that translate into excellent in-band RF measurements – Be careful to consider ResBW / throughput tradeoffs in scope-based FFT measurements – Oscilloscopes offer the widest analysis bandwidth to address the latest pulse and communications oriented applications – The noise density of new scopes is better than you might have realized, making them applicable to small signal applications – Scopes with FFTs are not a replacement for vector signal analyzers – Scopes combined with VSA software become a powerful wideband RF measurement suite Using your scope to make RF measurements Page 30

Keysight Oscilloscopes for High-Quality RF Measurements – S-Series with up to 8 GHz bandwidth – 90000A Series with up to 13 GHz bandwidth – 90000X Series with up to 32 GHz bandwidth – Z-Series with up to 63 GHz bandwidth Using your scope to make RF measurements Page 31

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Questions? Using your scope to make RF measurements Page 33

Backup Page 34

Time and Frequency Domain Translation When you say Time hears Frequency hears Bandwidth DC to a BW Bandwidth around a center frequency Wideband 1GHz or more 10MHz or more DC DC (like a battery) Anything less than 9KHz Channel Connector on front of instrument Communication medium Port Simulation term Connector on front of instrument Decimate Downsample Filter and then downsample Realtime Nyquist max sample rate. Post processing OK. Gap free processing. 50 Ohm termination 50 Ohms to ground- or (for BERTs and some probes) to a Vterm. 50 Ohms AC coupled. Page 35

- Learn techniques and tools to allow long target capture time, necessary to evaluate prototypes Using your scope to make RF measurements 3 . RF measurement suite 30 Scopes for RF measurements Using your scope to make RF measurements . Page Keysight Oscilloscopes for High-Quality RF