Agilent Technologies 93000 SOC Series Training Manual page 276

Lesson 7 – Executing the DAC Distortion Test
Coherent Sampling
In order to obtain a pure spectrum, coherent sampling has to be
established.
Unit Test Period (UTP)
1/F
in
M
cycles
N
1/F
sample
M F
cycles in
=
N F
points sample
Coherent Sampling
Sampling Parameters and FFT
When setting up coherent sampling, the following condition must
be met.
Condition for Coherent Sampling
276
Fundamental
Frequency
= 3
FFT
1/UTP
DC
= 16
points
M
cycles
2nd
Harmonic
Nyquist
Frequency
Fin
F
sample
2
= 3
N / 2 = 8
points