TD_DFFT Function Example | Teradata Vantage - TD_DFFT Example - Teradata Vantage

Example: Using TD_DFFT with Generated Data

TD_GENSERIES4FORMULA Call to Generate Data

EXECUTE FUNCTION INTO VOLATILE ART(GeneratedData)
TD_GENSERIES4FORMULA(
SERIES_SPEC(TABLE_NAME(genData), SERIES_ID(ID), ROW_AXIS(SEQUENCE(ROW_I)),
PAYLOAD( FIELDS(MAGNITUDE), CONTENT(REAL))
),
FUNC_PARAMS(Formula('Y = 4.0*sin(6.283185307179586476*X1/200.0) +
4.0*sin(6.283185307179586476*X1/16.0 + 3.14159265358979323/4.0) +
4.0*sin(6.283185307179586476*X1/8.0 + 3.14159265358979323/2.0) +
4.0*sin(6.283185307179586476*X1/4.0 + 3.14159265358979323/8.0)'))
);

TD_DFFT Call

EXECUTE FUNCTION INTO VOLATILE ART(DfftRaw_INTEGRAL)
TD_DFFT(
SERIES_SPEC( TABLE_NAME(GeneratedData), SERIES_ID(ID), 
   ROW_AXIS( SEQUENCE(ROW_I) ), 
   PAYLOAD( FIELDS(MAGNITUDE), CONTENT(REAL)) ),
FUNC_PARAMS( FREQ_STYLE("K_INTEGRAL"), HUMAN_READABLE(1) ),
OUTPUT_FMT( CONTENT(AMPL_PHASE_RADIANS) ) );

TD_DFFT Output

Display the primary RETURNS TABLE with this statement:

SELECT * FROM DfftRaw_INTEGRAL WHERE Amplitude_Magnitude > 1.0;

Amplitude_Magnitude > 1.0;
ID ROW_I AMPLITUDE_MAGNITUDE PHASE_MAGNITUDE
----------- ----------- ---------------------- ----------------------
1 -100 8.00000000000000E 002 -3.92699081698714E-001
1 -50 7.99999999999999E 002 -7.85398163397436E-001
1 -25 7.99999999999998E 002 3.92699081698730E-001
1 -2 8.00000000000000E 002 1.53938040025900E 000
1 2 8.00000000000000E 002 -1.53938040025900E 000
1 25 7.99999999999998E 002 -3.92699081698730E-001
1 50 7.99999999999999E 002 7.85398163397437E-001
1 100 8.00000000000000E 002 3.92699081698714E-001