1. By default, all analog samples are stored using signed 16-bit integers regardless of the resolution of the original data. The actual resolution and format of the data may be recorded as indicated by setting the optional ANALOG:FORMAT parameter to the value “UNSIGNED” and the optional ANALOG:BITS parameter to the actual number of bits used, i.e., the value 12 or 16.
2. If the ANALOG:FORMAT parameter is “UNSIGNED” then the ANALOG:OFFSET parameter must be interpreted as an unsigned integer.
3. If the ANALOG:FORMAT parameter does not exists then assume that the analog data is signed. This will be correct most of the time.
4. The possibility of 16-bit integer overflow exists when applying the ANALOG:OFFSET parameter to the sampled 16-bit analog data. It is recommended that all applications perform analog scaling calculations with more than 16-bits of resolution (typically 32-bit) to allow for internal math overflow or convert the C3D file format to floating point first.
5. Some software applications “auto-zero” analog data values by adjusting the ANALOG:OFFSET parameter. Thus, for example, 12-bit analog data could easily have varying ANALOG:OFFSET values that are close to 2047 but vary from channel to channel.