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Troubleshooting
This section contains some common questions about AO Series devices. If your questions are
not answered here, visit the
Calculating Frequency Resolution
How can I calculate the frequency resolution of the analog output on the AO Series device?
The analog frequency (f
the number of samples per cycle (S
The onboard 20 MHz clock that generates f
suppose you want to generate a sine wave at 2 kHz with 50 samples per cycle. Substitute 2 kHz
and 50 samples into the previous equation to get:
So f
equals 100 kHz. The 20 MHz clock must be divided by 200 as shown by:
u
Suppose now you want to slightly increase or decrease the frequency of the sine wave. The
closest available update clock you can generate occurs using a divisor of 199 or 201. If you
choose 201, f
equals 99.5 kHz, as the following equation shows:
u
In this case, f
equals 1.99 kHz, according to the following equation:
a
The smallest frequency change that you can generate in this case is approximately 10 Hz.
ni.com/support
) you can generate is determined by the update clock frequency (f
a
):
c
f
u
2 kHz
20 MHz
-------------------
200
20 MHz
-------------------
201
99.50 kHz
f
=
------------------------ -
a
50
and search for your model number.
f
u
=
---- -
a
S
c
can only be divided by an integer. For example,
f
u
=
----- -
50
100 kHz
=
99.50 kHz
=
1.99 kHz
=
B
© National Instruments | B-1
) and
u
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