Signal processor

DETAILED DESCRIPTION An object of the present invention is to provide a signal processor of the above known type, but which reduces the need for clipping of the output signal and which thus allows the use of a cheaper DAC converter without possible loss of information.
According to the present invention, this is achieved due to the fact that said signal processor further includes a cascade connection of third means, said first means and second means, said second means being adapted to activate a control signal at a control terminal thereof if the amplitude of said output signal exceeds a predetermined amplitude threshold, said third means being adapted to perform a predetermined transformation of said input vectors upon said control signal being activated, said second means further being adapted to provide said output signal at an output terminal of said signal processor.
Indeed, the amplitude value of the output signal is accurately modelled as a Gaussian Random Variable due to the fact that the output signal equals the sum of a plurality of modulated signals.
The probability P that the amplitude of the output signal is bigger than the amplitude threshold and that the input vectors are transformed by the third means, is smaller than one, i.
e.
P<1.
As a result, the first means provides an output signal for which the probability that the amplitude is larger than the amplitude threshold is P.
P which is smaller than P.
The latter probability is unconditional due to the predetermined transformation.
A characteristic feature of the invention is that said plurality of input vectors are represented in said signal vector plane by a plurality of orthogonal coordinate pairs and that said first means is adapted to process said output signal by means of an inverse fast fourier transformation of said plurality of orthogonal coordinate airs.
In this way, the first means provides the output signal in a very reliable way.
Another characteristic feature is that said predetermined transformation comprises a rotation in said signal vector plane of said input vectors over respective predetermined angles