Formation of signal corrupted with noise

Function forms a signal corrupted with noise and signal-to-noise ratio has a specified value

Function SNRS forms an array of a signal which is corrupted with noise and signal-to-noise ratio has a specified value SNR.
We suppose that SNR was defined as a ratio of the root-mean-square value of amplitudes of a signal A(s) and a noise A(n). It is supposed that value of SNR was expressed in decibels (dB). It is supposed, too, that both the signal and the noise were measured at the same points, within the same bandwidth, and across the same impedance. Thus, for calculations we used the following formula: SNR = 20log10(A(s)/A(n)).
If array of noise has length not equal to length of array of signal then array of noise will be automatically resized to fit length of array of signal.
If length of array "noise" less than length of array "signal" then we can change type of noise aggression and apply noise only to the first part of array "signal".
Both array "signal" and array "noise" should have floating point format.
Though function SNRS is universal it is recommended to use function SNRN for audio signal.