A method and apparatus for focusing a device for imaging a biologic sample is provided. The RAIL system could create a servo pattern of a recording-head trajectory of a hard disk drive in a master for magnetic-contact printing. The first and second transmitted data streams are transmitted substantially simultaneously on separate transmission channels to at least one receiver. The load network can include multiple loads each to be individually controlled to receive one of the multi-phase IF signals. Each token bucket filter selectively passes the corresponding assigned data frame to the corresponding priority queue based on a determined availability of at least a required number of tokens corresponding to a determined size of the corresponding assigned data frame. The method includes the steps for: as a preliminary test, presenting standard test stimulus to a subject; searching the wave V peak and SN10 peak; and as a main test, presenting test stimulus of each frequency, searching the minimal intensity and determining objective hearing threshold of each frequency.