JDS Uniphase BACKREFLECTION METER RM3750 User Manual - page 31
RM3 SERIES BACKREFLECTION METER
USER’S MANUAL
10112341 Rev 002
Page 30 of 39
Figure 9: Measuring Relative Power
Power Accuracy
The absolute accuracy of power measurements made with the RM meter is dependent on the
power level to be measured. The RM meter does not measure power levels below -50 dBm
unless the dark signal from extraneous sources (
I
D
) is stored.
To ensure accurate power measurements below -65 dBm, store
I
D
frequently.
The value of
I
D
can change with temperature fluctuations.
Data Logging Using the Foot Pedal
The RM meter is supplied with a foot pedal for convenient data logging to either a computer or
printer. Data logging operates at a baud rate of 2400.
To use the foot pedal:
1. Ensure the computer or printer is connected to the RS232C or IEEE 488 (GPIB) port at the
back of the meter.
2. If the foot pedal is not already operational, connect the foot pedal plug to the Log jack on
the rear panel of the meter.
3. Press the foot pedal. The message “Log” appears on the right-hand side of the front-panel
display, and the most recent measurements made are sent to the computer or printer
through the RS232 serial or IEEE 488 (GPIB) port.
Messages and Symbols
The messages and symbols displayed by the RM meter are described in Table 7.
Table 7: RM Meter Display Messages and Symbols
Display
Description
RMXXXXB VERY.Y
Displayed momentarily during the power-up sequence and indicates