  A technique that allows a harmonic oscillator to be used as a wideband,
vector signal analyzer is described and demonstrated using a single trapped
40Ca+ ion cooled near its motional ground state. Further, the analyzer is shown
to be compatible with both quantum amplification via squeezing and measurement
in the Fock basis, allowing performance beyond the standard quantum limit. In
addition to providing an attractive platform for quantum sensing of small
fields, the technique allows in situ calibration of qubit control lines in
systems using quantum harmonic oscillators and transduction of external,
non-resonant drives into oscillator motion. This technique is extendable to
other quantum harmonic oscillator systems.
