mazerom wrote:

exactly sir but im referring to the spectral content of the signal its
carrier and sidebands for that matter.how significant will be the
doppler shift of its spectral components other than its carrier
signal?thanks


Doppler shift is applicable to all frequency components of a signal.

It is a percentage change of the base frequenc[ies] as a function of the
rate of closure or divergence between an observer and the originator of
the signal.

So, for FM it applies to the carrier frequency at ONE doppler shifted
value. It applies to the individual frequency [secondary] components as
another doppler shifted component for each frequency. In practice, the
doppler shifted frequenc[ies] among the secondary components are
extremely small when compared to the prime frequency.

For spread spectrum, it is applicable to ALL frequencies.
For AM, it is applicable to ALL frequencies.
For SSB, it is applicable to ALL frequencies.
For CW it is applicable to ALL frequencies
For FM/NBFM/WBFM, it is applicable to ALL frequencies.
For unmodulated carriers, it is applicable to ALL frequencies.
For audio, it is applicable to ALL frequencies.
For ...., it is applicable to ALL frequencies.