Programmer Guide/SPU Reference/UCONV

Apply amplitude or frequency scale conversion.

[SPU UCONV X TYP A B OUT Y]

input	description	data type	value type	default value
X	input date	number, vector	variable
TYP	conversion (see description)	number (int.), string	constant	0
A, B	conversion parameters (see description)	number	variable
output	description	data type	value type	comment
Y	converted input data	same type as A	variable

Description

This atom performs a conversion of the input X (containing physical data) into another unit or domain. The type of conversion is controlled by the selection input TYPE and the parameter inputs A and B. The input data can be stored in a number or vector. If the input is a vector, the conversion is applied to all elements.

TYPE	default A	default B	applied transformation /conversion
0 or LINEAR	1	0	Linear transformation. Parameter A is used as slope and parameter B as offset Y = A . X + B {\displaystyle Y=A.X+B\!} $Y=A.X+B\!$
1 or HZ2CENT	1	0	Convert frequency from Hertz to Cents. Parameter A is used as reference frequency and B as offset in Cents. Y = 1200 ⋅ log 2 ⁡ ( X A ) + B {\displaystyle Y=1200\cdot \log _{2}\left({\frac {X}{A}}\right)+B} $Y=1200\cdot \log _{2}\left({\frac {X}{A}}\right)+B$
2 or CENT2HZ	1	0	Convert frequency from Cents to Hertz. Parameter A is used as reference frequency and B as offset in Cents. Y = A ⋅ 2 X − B 1200 {\displaystyle Y=A\cdot 2^{\frac {X-B}{1200}}} $Y=A\cdot 2^{\frac {X-B}{1200}}$
3 or HZ2BARK	-	-	Convert frequency from Hertz to Barks. Uses the transformation published by Zwicker and Fastl (1990). The parameters A and B are ignored.
4 or BARK2HZ	-	-	Convert frequency from Barks to Hertz. Uses an iteration method that minimizes the distance to the forward conversion algorithm. The parameters A and B are ignored.
5 or LIN2LOG	1	20	Convert from linear to logarithmic scale. Parameter a is used as reference value and b as factor: y=b.log10(x/a)
6 or LOG2LIN	1	20	Convert from logarithmic to linear scale. Parameter a is used as reference value and b as factor: y=a.10x/b
7 or HZ2MEL	-	-	Convert from Hertz to Mel. The parameters A and B are ignored.
8 or MEL2HZ	-	-	Convert from Mel to Hertz. The parameters A and B are ignored.
9 or HZ2ERB	-	-	Convert from Hertz to ERB (Equivalent Rectangular Bandwidth). The parameters A and B are ignored.
10 or ERB2HZ	-	-	Convert from ERB (Equivalent Rectangular Bandwidth) to Hertz. The parameters A and B are ignored.

See also

<SP-atoms>