Keysight Technologies 3458A Guide D'utilisation page 498

E High Resolution Digitizing With the 3458A
Figure E-13
The 3458A offers two input paths. The differences are that the direct ADC path
(DCV) offers up to 160 kHz bandwidth up to a sampling rate of 100,000 samples
per second; the track-and- hold path offers 12 MHz bandwidth at a sampling rate
of 50,000 readings per second. Both paths exhibit single pole roll-off; both are
nominally three dB down (half power) at the bandwidth point. Hence, two errors
can creep into your measurements: aliasing and amplitude roll-off. In the
track-and-hold path aliasing can be eliminated by increasing the effective
sampling rate up to 100 MSamples/s and the track-and-hold circuit can be
characterized for amplitude roll-off over the band of interest to compensate for
the roll-off. In the case of the DCV path, the only real solution to aliasing is to
supply a low pass analog filter. See
498
Analog-to-digital converters that exhibit non-linearity errors
cause spurious responses that averaging will not remove. The
3458A is linear to 16 bits at 100,000 readings/s.
Figure E-14.
Keysight 3458A User's Guide