
42-6 Time and Frequency
frequency metrology because it has the advantage of being convergent for most types of oscillator noise.
e e
quation
f
or
A
DEV
u
sing
f
requency
m
easurements
a
nd
n
onoverlapping
s
amples
i
s
σ τ
y i i
i
M
M
y y( )
( )
=
−
−
( )
+
=
−
∑
1
2 1
1
2
1
1
(42.11)
where
y
–
i
is the ith in a series of M dimensionless frequency measurements averaged over a measurement
or sa
mpling
in
terval
de
signated
as τ. No
te
th
at
wh
ile
cl
assical
de
viation
su
btracts
th
e
me
an
fr
om
ea
ch
me
asurement
be
fore
sq
uaring
th
eir
su
mmation,
AD
EV
su
btracts
th
e
pr
evious
da
ta
po
int
. Si
nce
st
ability
is a me
asure
of fr
equency
u
ctuations
an
d
no
t
of fr
equency
o
set,
th
e
di
erencing
of