A child swing comprises a frame including first and second rear legs and first and second housings. The membrane also has a metal-containing gel which has been hydrolysed andor condensed from a metal alkoxide starting material and which is deposited in the polymer andor is chemically bonded to the polymer. A powder blend, whose average composition corresponds to the component alloy constitutes the solder material, the blend comprising at least one elementary powder of the component alloy as one powder type andor a pre-alloy of the component alloy. For example, the particular timing recovery and automatic gain control schemes used by the receiver portion of the second modem may be optimally initialized with a synchronization signal having a specific length, amplitude, or spectrum.