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Frequency response of DMM's

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HKJ:
I am comparing a couple of high-end DMMs (Article coming later) and wondered about their frequency response. This is easily checked with my TestController and I decided to check all the meters within easy reach from my bench (That includes bench meters):
http://lygte-info.dk/info/DMMFrequencyResponse%20UK.html

I am lazy, i.e. the test only include meters that connect to TestController and could be tested automatic.

All test are run from 50 to 500kHz at 1V.



And this time I included both Fluke 189 and Gossen Energy.

BeBuLamar:
So either my Fluke 189 or 289 is good enough to use on audio equipment. Thanks.

Kleinstein:
The frequency response of the DMMs in AC mode can depend on the amplitude: there may be a slew rate limit in some cases, effecting a voltage rather close to the full scale. At the low end the analog RMS to DC converters tend to get slower.

HKJ:

--- Quote from: Kleinstein on May 18, 2021, 11:41:29 am ---The frequency response of the DMMs in AC mode can depend on the amplitude: there may be a slew rate limit in some cases, effecting a voltage rather close to the full scale. At the low end the analog RMS to DC converters tend to get slower.

--- End quote ---

A significant factor is the compensation of the input divider, it is a roughly 10Mohm resistor going into a amplifier or ADC with some input capacity. At 100kHz a 1pF capacitor has 1.6Mohm, i.e. without some sort of compensation across the input resistor you are not going to see anything nearly linear.

joeqsmith:

--- Quote from: Kleinstein on May 18, 2021, 11:41:29 am ---The frequency response of the DMMs in AC mode can depend on the amplitude: there may be a slew rate limit in some cases, effecting a voltage rather close to the full scale. At the low end the analog RMS to DC converters tend to get slower.

--- End quote ---
Should be easy enough to repeat the test at a few levels. 

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