Table of Contents
Advertisement
Average power can be measured directly using the internal power meter of the
HP 83487A, by pressing: blue Shift key, More meas key on the numeric keypad and then
the Avg Power softkey. Then select the data to be reported in dBm.
Average power measurements are made independent of the amplifier in the
optical receiver and are accurate up to an average input power level of 500 µW
or –3.0 dBm (2000 µW peak power input).
If overshoot is present, the correct level of attenuation is the difference
between the average power and –10 dBm. For example, a –3 dBm average
power signal would require 7 dB of attenuation (–3 dBm minus –10 dBm =
7 dBm, which requires a 7 dB attenuator). This is based upon the assumption
of a worst case overshoot of 100%. The end result is that the maximum peak
signal at the instrument input must be below 400 µW (–4 dBm). Again, this is
peak power and should not be confused with average power. Attenuation is
not required for signals that do not exceed 400 µW peak.
page 5-8
shows the conversion from average power to peak power when the
overshoot is 100% (the peak power is double the "1" level power), and the
attenuation needed to make measurements for power levels of these magni-
tudes. Note that the current maximum average power allowed by the stan-
dards is –5 dBm.
Measuring High Power Waveforms
Table 5-1 on
Reference
5-7
Advertisement
Table of Contents
