B
Electronic Calibration of the 3458A (Product Note 3458A-3)
124
Keysight 3458A Calibration Manual
of the input signal, which can be shown using
Fourier transform theory.
Figure 5.
The frequency response of the AC attenuator is adjusted based
on two readings taken at specific delays after application of a
step input. Shown in this drawing are two different
uncompensated responses representing under shoot and
overshoot.
The 3458A multimeter produces the required
step input voltage. Then, its analog-to-digital
converter samples the attenuator output. These
measurement results determine constants used
to control the output of the flatness adjusting
DAC. Control of the DAC output effectively
changes the resistance in one leg of the
attenuator to produce the desired maximally flat
response. Calibration constants are separately
determined for each AC range.
AC converters normally have turnover errors. A
standard metrology practice is to use ± signals to
correct these errors. A shorter time between
samples of these ± signals reduces 1/f noise.
Thus the 3458A multimeter samples at a higher
rate to give 1/f rejection, as indicated in Figure 6.
Figure 6.
Positive and negative signals are internally provided to eliminate
turnover errors. This input is also sampled at a higher rate to
reject 1/f noise.
These signals are applied to the RMS converter
and track-and- hold amplifier paths. Attenuated
or amplified levels produce inputs appropriate for
each of six AC voltage ranges. The 3458A
multimeter measures the correct values of these
DC levels with the DC input path that has already
been calibrated. These known values are
compared with the measured gains of the RMS
converter and track-and-hold amplifier paths.
Gain constants are the result of transferring
accuracy between ranges, as discussed under
DC gain adjustments.
Gain of the RMS converter is non-linear at
one-tenth full scale. This non-linearity is
effectively an offset corrected by applying the
chopped DC levels at one-tenth the full-scale
voltage.
Содержание 3458A
Страница 1: ...Keysight 3458A Multimeter Calibration Manual ...
Страница 10: ...10 Keysight 3458A Calibration Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK ...
Страница 14: ...14 Keysight 3458A Calibration Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK ...
Страница 16: ...16 Keysight 3458A Calibration Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK ...
Страница 18: ...18 Keysight 3458A Calibration Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK ...
Страница 39: ...Adjustment Procedures 3 Keysight 3458A Calibration Manual 39 Figure 3 1 4 terminal short ...
Страница 52: ...3 Adjustment Procedures 52 Keysight 3458A Calibration Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK ...
Страница 59: ...Performance Verification Tests 4 Keysight 3458A Calibration Manual 59 Figure 4 1 General test procedure ...
Страница 109: ...Command Summary 5 Keysight 3458A Calibration Manual 109 Related commands ACAL CAL SECURE ...
Страница 116: ...A Specifications 116 Keysight 3458A Calibration Manual THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK ...