We　propose　a　scheme　to　generate　a　superposition　of　several　coherent　states　with　arbitrary　coefficients　on　a　line　in　phase　space　and　directly　measure　the　Wigner　characteristic　function　for　the　motion　of　a　trapped　ion.　Unlike　previous　schemes　for　motional　quantum-state　engineering　and　endoscopy,　the　present　scheme　works　in　the　strong-excitation　regime,　which　may　be　of　experimental　importance　in　view　of　decoherence.