  For a virtual knot $K$ and an integer $r$ with $r\geq2$, we introduce a
method of constructing an $r$-component virtual link $L(K;r)$, which we call
the $r$-multiplexing of $K$. Every invariant of $L(K;r)$ is an invariant of
$K$. We give a way of calculating three kinds of invariants of $L(K;r)$ using
invariants of $K$. As an application of our method, we also show that
Manturov's virtual $n$-colorings for $K$ can be interpreted as certain
classical $n$-colorings for $L(K;2)$.
