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6.7.9 PowerCalcForMap

6.7.9.1 Outline of the node

This node converts multichannel complex spectra of Map<int, ObjectRef> type IDs into real power/amplitude spectra.

6.7.9.2 Necessary files

No files are required.

6.7.9.3 Usage

When to use

This node is used to convert complex spectra into real power/amplitude spectra when inputs are Map<int, ObjectRef> type. When inputs are of Matrix<complex<float> > type, use the PowerCalcForMatrix node.

Typical connection

Figure 6.107 shows an example of the usage of the PowerCalcForMap node. A Map<int, ObjectRef> type complex spectrum obtained from the MultiFFT node is converted into Map<int, ObjectRef> type power spectrum and input to the MelFilterBank node.

\includegraphics[width=.8\textwidth ]{fig/modules/PowerCalcForMap}
Figure 6.107: Example of a connection of PowerCalcForMap 

6.7.9.4 Input-output and properties of the node

Table 6.79: Parameters of PowerCalcForMap 

Parameter name

Type

Default value

Unit

Description

POWER_TYPE

string 

POW

 

Selection of power/amplitude spectra

Input

INPUT

: Map<int, ObjectRef> type. Complex matrices of Matrix<complex<float> > type are stored in the ObjectRef part.

Output

OUTPUT

: Map<int, ObjectRef> type. Real matrices of power/absolute values are stored in the ObjectRef part for each element of the complex matrices of the inputs.

Parameter

POWER_TYPE

: string type. Selection of power (POW) or amplitude (MAG) spectra for the output.

6.7.9.5 Details of the node

The real matrix Ni,j of the output for the complex matrix Mi,j of an input (i,j indicating the rows and columns of the index, respectively) is obtained as:

  Ni,j = Mi,jMi,j  (if POWER\_ TYPE=POW),    
  Ni,j = abs(Mi,j)  (if POWER\_ TYPE=MAG),    

Here, Mi,j indicates the complex conjugate of Mi,j.