The second problem is that data is only recorded at discrete times. We do not know what the signal - for example, the sound wave - is doing between the measurements. More than one possible wave can fit. This problem is called [[aliasing]]; it can also be mitigated by taking more frequent measurements but never totally solved. | The second problem is that data is only recorded at discrete times. We do not know what the signal - for example, the sound wave - is doing between the measurements. More than one possible wave can fit. This problem is called [[aliasing]]; it can also be mitigated by taking more frequent measurements but never totally solved. |