All C3D files support a single sample rate for POINT data and a single sample rate for ANALOG data. The ANALOG sample rate is always either the same as the POINT rate or an exact multiple of the POINT rate. While this may seem restrictive, this requirement ensures that the ANALOG data is always exactly synchronized with the POINT data. In addition, this restriction allows any application to easily calculate the exact location of any frame of data within the C3D file.
One consequence of this limitation is that all analog data is sampled at the highest sample rate required by the channel with the highest frequency signals.