this topic lasted longer than I thought, and generated more responses.....
My original objection to the SS approach stems from experience in the EMC
business. While it may seen sufficient that the amplitude of an undesired
signal is reduced, what often occurs is that the CW nature of a clock
harmonic ( is a nuisance agreed, but ) does not corrupt circuits. However,
when you apply modulation, the RF gets the signal into a circuit, and
somewhere there is a demodulator ( intentional or otherwise ) that
demodulates the RF and responds to the modulation.
I guess in a nutshell, just killing the amplitude of a signal will get you
through a test, but may not meet the intent of the testing, which is not to
interfere with other systems. This is the EMC engineers point of view, I'm
open to others...
L F Research EMC Design and Test Facility