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Characteristic information about generated signal



S = info(nco) returns a structure containing the characteristic information, S, about the dsp.NCO System object™, nco.


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The characteristic information of the NCO object is defined by the following fields:

  • NumPointsLUT — Number of data points in the lookup table.

  • SineLUTSize — Quarter-wave sine lookup table size in bytes.

  • TheoreticalSFDR — Theoretical spurious free dynamic range (SFDR) in dBc.

  • FrequencyResolution — Frequency resolultion of the NCO.

To obtain the above characteristics for a specific NCO object, call the info function on the object.

nco = dsp.NCO
nco = 
  dsp.NCO with properties:

                PhaseIncrementSource: 'Input port'
                   PhaseOffsetSource: 'Property'
                         PhaseOffset: 0
                              Dither: true
                       NumDitherBits: 4
                   PhaseQuantization: true
         NumQuantizerAccumulatorBits: 12
    PhaseQuantizationErrorOutputPort: false
                            Waveform: 'Sine'
                     SamplesPerFrame: 1
                      OutputDataType: 'Custom'

  Show all properties

ans = struct with fields:
           NumPointsLUT: 1025
            SineLUTSize: 2050
        TheoreticalSFDR: 84
    FrequencyResolution: 1.5259e-05

The fields and their corresponding values change depending on the settings of the object. For instance, if the PhaseQuantization property is set to false, the TheoreticalSFDR field does not appear.

nco.PhaseQuantization = false;
ans = struct with fields:
           NumPointsLUT: 16385
            SineLUTSize: 32770
    FrequencyResolution: 1.5259e-05

Input Arguments

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Numerically controlled oscillator, specified as a dsp.NCO System object.

Output Arguments

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Characteristic information about the dsp.NCO System object, returned as a structure, S. The number of fields of S and their values vary depending on the property value settings of nco. The possible fields and their values are:

NumPointsLUTNumber of data points for lookup table. The lookup table is implemented as a quarter-wave sine table.
SineLUTSizeQuarter-wave sine lookup table size in bytes.
TheoreticalSFDRTheoretical spurious free dynamic range (SFDR) in dBc. This field applies when you set the PhaseQuantization property to true.
FrequencyResolutionFrequency resolution of the NCO in Hz. The sample time of the output signal is assumed to be 1 second.

Data Types: struct

Version History

Introduced in R2012a

See Also