SpHEAR/calibration/src/clipdb.m

%% [clipped] = clipdb(s,cutoff)

%% Clip magnitude of s at its maximum + cutoff in dB.
%% Example: clip(s,-100) makes sure the minimum magnitude
%% of s is not more than 100dB below its maximum magnitude.
%% If s is zero, nothing is done.
%%
%% https://ccrma.stanford.edu/~jos/fp2/Matlab_listing_clipdb_m.html

function [clipped] = clipdb(s,cutoff)
  clipped = s;
  as = abs(s);
  mas = max(as(:));
  if mas==0, return; end
  if cutoff >= 0, return; end
  thresh = mas*10^(cutoff/20); % db to linear
  toosmall = find(as < thresh);
  clipped = s;
  clipped(toosmall) = thresh;
end