Document type:
Title:
Revision date:
Re vision:
User's Manual (MUT)
N1145 Quad Scaler and Preset Counter/Timer
05/11/2003
0
NPO:
Filename:
Number of pages:
Page:
00115/01:N1145.MUTx/00
N1145_REV0.doc
14
14
The uncertainty of the measurement of an absolute time delay is therefore equal to the
clock period.
For frequency measurements it is:
∆ƒ
i
=ƒ
max
−ƒ
min
=
(Mc)
/
(N
τ
)
−
(Mc-1)
/
(N
τ
)
=1/
(N
τ
)
where
∆ƒ
i is the absolute frequency uncertainty. The relative frequency uncertainty is
then:
∆ƒ
i
=
1
−
(Mc)
and since for a given (constant) frequency Mc(=N
ƒτ
) is proportional to N, the percent
accuracy is increased by increasing N.
