Translation,　dilation,　and　modulation　are　fundamental　operations　in　wavelet　analysis.　Affine　frames　based　on　translation-and-dilation　operation　and　Gabor　frames　based　on　translation-and-modulation　operation　have　been　extensively　studied　and　seen　great　achievements.　But　dilation-and-modulation　frames　have　not.　This　paper　addresses　a　class　of　dilation-and-modulation　systems　in　L-2(R+).　We　characterize　frames,　dual　frames,　and　Parseval　frames　in　L-2(R+)　generated　by　such　systems.　Interestingly,　it　turns　out　that,　for　such　systems,　Parseval　frames,　orthonormal　bases,　and　orthonormal　systems　are　mutually　equivalent　to　each　other,　while　this　is　not　the　case　for　affine　systems　and　Gabor　systems.