4.5 Ground electronics noise
The DSN ground electronics have been carefully designed to minimize phase/frequency noise and
produce only a small contribution to the overall error budget. (Here I distinguish this noise
from the white phase noise due to finite signal-to-noise ratio; see Section 4.7). In a controlled
test at DSS 25 (antenna stationary, FTS common to the transmit and received chains and
thus cancelled in this zero two-way light time test) the sum of the noises from the exciter,
transmitter, downconversion electronics, and receiver was measured (Figure 5). The power
spectrum of those test data is shown in [1
]; the corresponding Allan deviation at 
= 1000 s is
2 
10–16.
). The power
spectrum of those test data is shown in [1