Complementing the features of the 2-antenna simulator. It was detected a requirement of adding a fixed-frequency signal into the simulation scheme. This is interpreted as a spectral line in observations (such as oxygen, sugar or other complex chemical compounds), useful for testing the sensitivity degree of the correlator when the antennas capture a weak single-frequency signal. For this, a PIC\texttrademark\ micro-controller is connected to a \ac{TTL} to RS232 converter that implements a special communications port for setting the desired tone through a \ac{DAC} connected to a \ac{VCO}, creating a \ac{DCO}. The micro-controller then manipulates the \ac{DCO} for adjusting a moving tone in the range of 0-2GHz that is converted by the 2-antenna simulator into a 2-4GHz spectral line, which is the frequency range accepted by \ac{DTX} units.