This core object implements a synchronous sample rate converter whose input sample rate / input block length and output sample rate / output block length are integer multiple of each others. This is also an infinite impulse response implementation (IIR).
The object operates in one of 2 modes:
- A predefined mode
- A free user mode
Before we delve into the details, there are some common configuration parameters between the two:
- The input block length needs to be set by the user
- The Biquad filter topology. Currently 2 topologies are exposed:
- Direct Form I
- Direct Form II
Free User Mode
In this mode the user can:
- select the input and output sample rates (as long as the relationship is an integer multiple)
- Number of biquad IIR filters to use for filtering
- pass in the filter coefficients to the embedded object filter
Predefined mode
In this mode, the filtering coefficients will be pre-determined based on the user selected combination (from a drop-down menu) of:
- input sample rate
- output sample rate
- number of biquads
For these pre-defined coefficients, the quality measures are as follows:
Signal to noise ratio: 80 dB
Total harmonic distortion: 2e-3f
Spurious free dynamic Range: 59 dB
Total harmonic distortion plus noise: -60 dB
Frequency response flatness: 3 dB