Frequency Response Analysis using Oscilloscopes

Bode gain & phase, power supply control loop response

Thanks for watching the Keysight Oscilloscopes Webcast Series!

Learn more about using digital storage oscilloscopes:

Check out our blog:

Like our Facebook page:

More about Keysight scopes:

Agenda:

Power Supply Design Trends 2:08

Output Ripple 3:11
(output noise, PARD, Power Integrity)
-common probes used 4:10
-Probing techniques & example measurements 6:39
--10:1 passive probe 7:56
--10:1 passive probe with probe socket 9:06
-Using FFT analysis to measure ripple 10:31
--10:1 vs 1:1 probe 13:29
--Use a Power Rail Probe (N7020A) 14:10

Power Supply Rejection Ration 18:58
(Power Supply Ripple Rejection)
-Physical Setup 21:21
-Setting up a PSRR measurement 22:47
-Measuring PSRR 24:40
-Oscilloscope vs Network Analyzer (VNA) 26:08

Control Loop response measurements 27:02
-Power supply transient response analysis 28:02
-DC-DC converter block diagram 28:19
-Typical Loop Gain Measurement 29:40
-Control loop response measurement configuration 31:42
-Control loop response physical test setup 34:00
-Setting up a control loop response measurement on the oscilloscope 34:46
-Control Loop Response (Bode plot) - Gain plot 36:17
-Control Loop Response (Bode plot) - Phase plot 37:47
-Manual phase margin measurement 38:52
-Oscilloscope vs Network Analyzer (VNA) 39:36

Oscilloscope vs Network Analyzer overview 40:30

Review & summary 44:31

Keysight Oscilloscope Portfolio 45:18

Recommended probes for power supply measurements 47:05

Additional Technical Resources 49:13

Live Q&A 50:28

[yaghiyahbrenner]

What a great talk thanks johnny much appreciated!

[mineown]

If only boards were always laid out with scope probing in mind we could file that ground lead where we file the parts never used, the "what's this do ?" parts and the manuals of course .
20:1 passive probe from a 1k resistor on a 50ohm coax, with the given drawbacks but the joy of just tacking the probe tips on but beware circuit loading though without ac coupling ... Life's all ups and downs with oscilloscopes.