Hello Lisunov,
The TG44A is a companion product to the SA44B and they are meant to operate together. The tracking generator (TG) is simply a CW generator that has been designed to operate with the SA44B to function as a Scalar Network Analyzer. Our software exposes this functionality to the user when both devices are present. Both devices are needed if you want this functionality.
If you have any further questions please email support@signalhound.com
Regards,
A.J.
