HP 83480A - Computation of Dbv; DC Valu

General Purpose Oscilloscope Menus
FFT Menu
Computation of dBV
Another common unit of amplitude is dBV.A0dBV signal is dened as
a 1 Vrms signal. You can convert a dBm reading to a dBV reading by
subtracting 13 dB.
dB V =20 log

0 : 707107 2 V
p
1 V

Which gives us:
dB V
=20
log

V
p
0
: 316228
V

+20
log

0
: 707107
2 0
:
316228
V
1
V

Therefore:
dB
V
=
dB
m
v
al
ue
0
13
:
01 dB
dc
value
F
or
eciency
reasons
,
the
FFT
computation
produces
a
dc
value
that
is
incorrect.
10-34