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Technical Digital Multimeters
Information
Digital multimeters convert analog signals to
digital information. In general, DMMs have a AC AC Digital
minimum of five typical functions. They are DC Attenuator Converter Display
AC Digital
voltage, AC voltage, DC current, AC current, and AC Output
resistance. While specifications vary, most DMMs DC DC Ports
DC A/D
can be described with block diagrams similar to HI
Attenuator Converter (IEEE-488,
Figure 1. Ohms USB,
Amps RS-232,
Ohms Ethernet)
Analog to Digital Conversion INPUT Ohms Precision
Technical information: Digital multimeters
Technical information: Digital multimeters
The A/D converts the analog input signal to a Precision Converter Reference
Shunts
digital output and is primarily responsible for
key instrument characteristics of reading speed, LO
linearity, resolution, normal mode rejection,
and precision. The digital output is shown or
obtained in several ways. One way is visually, via
the front panel with a display of digits and other Figure 1: DMM Block Diagram
information. Another way is electronically, with
results sent via a port (GPIB, RS-232, USB, or
Ethernet) to a computer for further processing.
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