The
Perseus has some kind of log-amp RSSI unit in the "front end".
I don't think so. Between the antenna and the
ADC (an LTC2206-14) the only active component is a THS4509
Wideband, Low-Noise, Low-Distortion, Fully-Differential Amplifier.
The incoming signal is then converted by the ADC to the numeric
realm, and any subsequent processing, S value computation
included, is performed by the accompanying Perseus software, which
knows which bandwidth has been selected by the user, and of course
the S value reported is referred to this bandwidth.
There are no uncertainties, as no analog stages are involved in
this process, all is done numerically.
If you don't believe me, ask Leif Asbrink, who has performed
extensive measurements with the Perseus hardware. And also the
Perseus HW/ Linrad SW combo is capable of accurately measuring the
incoming dBm value at the antenna terminal, which then relates
directly to the S value.
