  We report the occurrence of vibrational resonance (VR) and the underlying
mechanism in a simple piecewise linear electronic circuit, namely the
Murali-Lakshmanan-Chua (MLC) circuit, driven by an additional biharmonic signal
with widely different frequency. When the amplitude of the high-frequency force
is tuned, the resultant vibrational resonance is used to detect the
low-frequency signal and also to enhance it into a high-frequency signal.
Further, we also show that even when the low-frequency signal is changed from
sine wave to square and sawtooth waves, vibrational resonance can be used to
detect and enhance them into high-frequency signals. These behaviors, confirmed
by experimental results, are illustrated with appropriate analytical and
numerical solutions of the corresponding circuit equations describing the
system. Finally, we also verify the signal detection in the above circuit even
with the addition of noise.
