Keysight N4372E, Руководство пользователя

Страница: 99 / 152

Keysight N4372E Lightwave Component Analyzer User’s Guide 99
Definition of Terms 6
It is interesting to note that delta voltages and currents are used as
opposed to RMS values. This is done because we deal with modulation
signals in describing lightwave transducers, where a change in optical
power is proportional to a change in electrical current or voltage.
The overall system forward gain is defined as:
Though the overall system gain is defined as an S-parameter, the
individual transfer functions of the EO and OE devices are typically defined
in terms of responsivities, because signals in both the optical and electrical
domain are used and optical signals do not lend themselves conveniently
to S-parameter definitions. Initially, the input impedance of the EO
converter and the output impedance of the OE converter will be assumed
to be Z
0
(thus S
11
and S
22
are zero).