Advanced Frequency Synthesis by Phase Lock

APPENDIX M

MASH PPSD

The PPSD due to a MASH modulator of order p is given by Miller and Conley [1991]^M1 as

where the resulting output PPSD is

That is, Eq. (M.1) gives the output PPSD except for the modification at higher f_m due to the loop roll-off. Equation (F.8.74) is corrected to this form in the revised footnote 8. In the region of greatest concern, where f_m « f_ref, this reduces to Eq. (F.8.75), which is essentially the same as Miller and Conley's Eq. (15),

or, in decibel units,

FIGURE M.1   MASH-11…quantization noise, linear plot, normalized. This is multiplied by H(f_m/f_ref) to give output PPSD due to MASH quantization.

A normalized version of Eq. (M.1) is plotted in Figs. M.1 and M.2.

It is shown in Appendix Q that

FIGURE M.2   MASH-11…quantization noise, log plot, normalized. ...