Abstract: A novel universal signal generator is disclosed comprising a composite system including a library or bank of signals consisting of pre-recorded signals of desired form which may be selected as the output of the apparatus. The output of the library or bank of signals may be varied in a manner which is permutated, systematic, random, jittered or wobulated, or in accordance with a predetermined mathematical curve. The output of the bank or library of signals, either as is or as modified, may be fed through a suitable correlator and/or a power spectra density comparator. The signal output, as is or as modified, or the output from the correlator or the power spectra density comparator may be modified by a suitable secondary modulator or second signal generator. A recording mechanism is provided for amplifying and recording a signal from within the system on separator recording tracks in both a forward and reverse direction.