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Models PH – Power Heads
Power heads have response variations (with respect to the reference frequency) at high frequencies.
Calibration factors ranging from ±3 dB are entered into the instrument memories at the desired frequencies.
Generally, calibration factors are within ±0.5 dB. These calibrations factors must be traceable to the National
Institute of Standards Technology (NIST) to be meaningful. This is accomplished by sending a standard
power head (Thermocouple type) to NIST or a certified calibration house and comparing this standard head
against each production head. The predominant error term is the uncertainty of the reference head, which is
typically 2% to 6%, depending on the frequency. See Figure 1-3. Calibration Factor Traceability.
Figure 1-3. Calibration Factor Traceability
1.4
SPECIFICATIONS
Refer to the AR data sheet at the end of this section for detailed specifications for your model.
Rev C
3
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