HP 34970A Measurement Fundamentals, Measurement Fundamentals

Chapter 8 Tutorial

Measurement FundamentalsMeasurement Fundamentals

This section explains how the HP 34970A makes measurements and discusses the most common sources of error related to these measurements.

The Internal DMM

The internal DMM provides a universal input front-end for measuring a variety of transducer types without the need for additional external signal conditioning. The internal DMM includes signal conditioning, amplification (or attenuation), and a high resolution (up to 22 bits) analog-to-digital converter. A simplified diagram of the internal DMM is shown below. For complete details on the operation of the internal DMM, refer to “Measurement Input” on page 60.

Analog			Analog to		To / From
	Signal	Amp		Main	Earth
Input			Digital		Referenced
	Conditioning			Processor
Signal			Converter		Section
					= Optical Isolators

The internal DMM can directly make the following types of measurements. Each of these measurements is described in the following sections of this chapter.

∙Temperature (thermocouple, RTD, and thermistor)

∙Voltage (dc and ac up to 300V)

∙Resistance (2-wire and 4-wire up to 100 MΩ)

∙Current (dc and ac up to 1A)

∙Frequency and Period (up to 300 kHz)

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