Figure 4-22
Remote Interface Operation
Use the following commands from your PC terminal to make the dB
measurement:
CALCulate:FUNCtion DB
CALCulate:STATe {OFF|ON}
CALCulate:STATe?
CALCulate:DB:REFerence {<
value
>|MINimum|MAXimum}
B. dBm
Definition
With dBm selected, a voltage measurement is displayed as the level of
power, relative to 1 milliwatt, dissipated through a reference
resistance. The reference resistance is adjustable in ATM3500A. The
calculation of dBm is defined as below:
mW
Z
V
dB
ref
in
m
1
/
log
10
2
×
=
Note:
※
in
V
is the input signal voltage.
ref
Z
is the reference resistance.
Note:
※
Change of reference resistance will not affect the stored
relative reference value.
The Zref is adjustable with a range from 50Ω to 8000 Ω. The
default value is 600 Ω.
94
or