# ArbitraryWave

Advanced Analysis Library Only

AnalysisLibErrType ArbitraryWave (int numberOfElements, double amplitude, double frequency, double *phase, double waveTable[], int tableSize, int interpolation, double arbitraryWave[]);

## Purpose

Generates an array that contains an arbitrary wave, with each cycle described by an interpolated version of the waveTable you specify. ArbitraryWave generates the output array x according to the following formula:

xi = amplitude × arb (phase + f × 360.0 × i)

where | arb(p) = WT(p modulo 360.0)
| f is frequency in cycles per sample

ArbitraryWave calculates WT(x) according to the following interpolation values:

where | ix = (int)x
| dx = x — (int)x
| (int) is the integral part of the variable x

You can use ArbitraryWave to simulate a continuous acquisition from an arbitrary wave function generator. The unit of the input phase is in degrees, and ArbitraryWave sets phase to
(phase + f x 360.0 x n) mod 360.0 before it returns.

## Parameters

Input
Name | Type | Description
numberOfElements | integer | Number of elements to generate in the arbitrary wave signal.
amplitude | double-precision | Amplitude of the resulting wave. The values in waveTable are multiplied by this amount when the function forms the arbitrary wave signal. Default Value: 1.0.
frequency | double-precision | Frequency of the resulting arbitrary wave signal. Frequency is in normalized units of cycles/sample. Default Value: 7.8125E-3 (1 cycle/128 samples).
waveTable | double-precision array | Contains equally spaced samples of one cycle of the generated signal.
tableSize | integer | Number of elements that the waveTable array contains.
interpolation | integer | Determines the type of interpolation used to generate the arbitrary wave signal from the waveTable samples. 0 = no interpolation 1 = linear interpolation Default Value: 0 (No Interpolation).
Output
Name | Type | Description
phase | double-precision | Points to the initial phase, in degrees, of the generated signal.
phase | double-precision | Upon completion of ArbitraryWave, phase points to the phase of the next portion of the signal. Use this parameter in the next call to ArbitraryWave to simulate a continuous function acquisition.
arbitraryWave | double-precision array | The generated arbitrary wave signal.

## Return Value

Name | Type | Description
status | AnalysisLibErrType | A value that specifies the type of error that occurred. Refer to analysis.h for definitions of these constants.