EEVblog 1521 - Common Mode Rejection Explained & Measured (CMRR)

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Published on December 26, 2022 11:10:02 PM ● Video Link: https://www.youtube.com/watch?v=vDe_BHvRpks

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Duration: 19:56

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What is Common Mode Rejection Ratio (CMRR) and how to measure it on a high voltage differential probe or differential amplifier. Using the new Rohde & Schwarz MXO4 oscilloscope.
https://www.rohde-schwarz.com/us/products/test-and-measurement/oscilloscopes/rs-mxo-4-oscilloscope_63493-1164992.html

Extended 30min version: https://www.youtube.com/watch?v=4gi2B3LrCww
Differential Probe How It Works: https://www.youtube.com/watch?v=GOlgaEK2Hsk
High Voltage Probe reverse engineering: https://www.youtube.com/watch?v=GOk1BYKSsOI&t=2s
Oscilloscope Standard Deviation noise measurement: https://www.youtube.com/watch?v=G8Qoj3TpO9A

Use coupon code ProbeyMcprobeFace for 15% of the HVP70 differential probe:
https://www.eevblog.com/product/hvp70/

Forum: https://www.eevblog.com/forum/blog/eevblog-1521-how-to-measure-differential-probe-cmrr/
00:00 - What is CMRR?
01:53 - Why twist the wires?
03:26 - Typical CMRR figures
04:51 - How to measure CMRR - The Setup
08:54 - Remote R&S Oscilloscope desktop view & settings
11:22 - Output to input voltage ratio
11:58 - Beware of DC offset
13:36 - Does the 20MHz CMRR measaurement match?
14:02 - Input referred measurement
15:02 - Compensating for the gain
16:29 - Automated Frequency Response Analysis

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