Conditions for Code Replacement of DSP System Objects with QHL

Each DSP System object™ that can be used with the Support Package for Qualcomm Hexagon processors requires specific conditions to allow code replacement with the Qualcomm Hexagon Library (QHL). You use this code replacement when generating C code from a model. The Qualcomm Hexagon Library (QHL) supports these DSP System object only when you set specific properties, as indicated in the following table:

	DSP System Object	Input Requirements	Parameter Requirements	Equivalent Functions in Replacement
1	`dsp.FIRFilter` (DSP System Toolbox)	Real values. `single` data type Input size must be even	Structure: `Direct Form`. NumeratorSource:: `Property or Input port`. Any frame-length if filter-length > 24. (or) 8 <= frame-length <=64 if 16<=filter length <=24	`mw_qhdsp_fir_af`
2	`dsp.FIRDecimator` (DSP System Toolbox)	Real values. `single` data type Input size must be even	Structure: `Direct Form`. NumeratorSource:: `Property or Input port or Auto`. Decimation Factor: `2,3,4` AllowArbitraryInputLength: false Decimation Factor: 2 or 3 AND FrameLength > 10 AND FilterLength >10.(or) Decimation Factor: 4 AND FilterLength < 40	`mw_qhdsp_decim_af`
3	`dsp.FFT` (DSP System Toolbox)	Real values. `single` data type Input size must be in powers of 2 Real : 16,32, …. Complex: 8,16,...	FFTImplementation: Auto BitReversedOutput: false FFTLength : <same as input length > (If FFTLengthSource is set to Property)	Real FFT `mw_qhdsp_fft_gen_twiddles_real_acf` `mw_qhdsp_acf_r1dfft_af` Complex FFT `mw_qhdsp_fft_gen_twiddles_complex_acf` `mw_qhdsp_c1dfft_acf`
4	`dsp.IFFT` (DSP System Toolbox)	`single` data type. Complex input values. Input size must be in powers of 2. Real : 32, 64 …. Complex: 16, 32...	FFT Length: same as input length (FFTLengthSource: is set to Property) Bit reversed order: false	Real FFT `mw_qhdsp_fft_gen_twiddles_real_acf` `mw_qhdsp_af_r1difft_acf` Complex FFT `mw_qhdsp_fft_gen_twiddles_complex_acf` `mw_qhdsp_c1idfft_acf`
5	`dsp.SOSFilter` (DSP System Toolbox)	`single` data type. Real values.	Filter structure: Direct-form II Transposed Coefficient sources: Property / Input port HasScaleValues: True / False Number of sections: 2 or 3 AND "FrameLength >= 50 (or) Number of sections>= 4 AND FrameLength >= 9	`mw_qhdsp_iir_af`

Note

Use only column-major layout for QHL/HVX replacements. For more information, see Row-Major and Column-Major Array Layouts.

Conditions for Code Replacement of DSP System Objects with QHL

See Also

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