What will happen if I send an analog signal through a digital regenerator?
A digital regenerator will ruin an analog signal.
Some analog signals will ruin some digital regenerators.
Most digital signals should have two distinct signal levels, labelled &quot;0&quot; and &quot;1&quot;.
A digital regenerator will attempt to force any input signal into a sequence of these two levels.
An analogue signal has an infinite number of values between certain fixed limits. It is vital to the fidelity of the signal that this range of possible values not be reduced (quantised) below some quality threshold. For an analog signal that threshold is much much greater than two.

(source: antonine-education.co.uk)
In the above diagram, a digital regenerator might convert the signal on the right to that on the left. If you fed this result to an analogue amplifier and into a loudspeaker the result would not be pleasant and the equipment might not survive.
More complex digital signals encode multiple bits of data per bit of signal - this may involve more than two signal states - for example more than two voltage levels. However it is very unlikely that a digital signal regenerator attempting to find such a digital signal in an unrelated analogue signal will happen to do anything useful.