A music reproduction apparatus comprises an audio player and a headphone. This avoids complications that can arise due to the packet data service being discontinued upon registration and the resulting inability to reach the mobile station. The selected correction vector incorporates dynamic aspects of pattern signals. One or more processing elements can store values associated with one or more flows into a structure without locking the structure. Techniques for generating separate bias voltages using a bidirectional and unidirectional current digital-to-analog converter are also disclosed.