This application is the program which uses iPhone as the simple low frequency oscillator.
It takes out a sound signal from the headphone terminal of iPhone and it uses it as the low frequency oscillator of 10 - 19999 Hz.

The form of the wave can be chosen from the "Sine wave", "Square wave", "Triangle wave", "Saw wave", "Free wave" and the "Distortion wave".
It chooses the "Oscillation mode" from the "Continuation wave", "Tone burst wave", "Sweep wave","White noise","Pink noise".
( As for the "Sweep wave", only the sin wave ).

In the "Free wave", it divides a wave in 1 cycle into the time axis in 10.
The corrugation can be freely generated by setting amplitude of vibration in each division position.
In the "Distortion wave", it generates the corrugation which synthesized second, third and forth of the fundamental frequency at the optional rate.
Also, it generates the corrugation which did a clip by the setting level.

It creates this app in the purpose to use signal output from the headphone terminal for the measurement and the test by connecting it with the other equipment.
When using the speaker of iPhone to output the sound signal of the continuation wave continuously, be careful because there is possibility to cause trouble.
Also, when hearing with the headphone, be careful because there is possibility to cause hearing impairments.

At this app, it is generating in a sampling rate 44100 Hz and 16bits.

In the case except the sine wave, when the frequency becomes high, it doesn't become a correct corrugation.
Either side channel is identical output (Monaural).

[ Usage ]

1. This app is composed of four views which are "Oscillator", "Setup", "Design", "Distortion".

2. "Oscillator" view
"Oscillator view" is the view which becomes basic and does the change of wave format, the change of the oscillation mode, the setting of a frequency, the setting of an output volume, and output's Srtart / Stop.
It begins oscillation when pushing the "Start" button, and after doing each setting and it stops it when pressing again.
During the oscillation, it cancels the automatic lock function of iPhone.
The output volume can be adjusted in 0% to 100 %.
When starting up this app, to protect a speaker, an output volume is initialized to 5 %.

3. "Setup" view
In the "Setup view", the oscillation mode sets each parameter in case of the "Tone burst wave", the "Sweep wave".
The "Tone burst wave" enters the number of the cycles of output on, and the number of the cycle of output off by the mode to repeat a set transmission frequency and dumbness.
As for the "Sweep wave", it sets a start frequency, an ending frequency, the number of the sweep time(seconds).

4. "Design" view
In the "Design view", it sets the "Free wave" shape.
It is possible to do four kinds of setting and it switch an optional corrugation at the button which is in the lower part.
The corrugation sets the amplitude of vibration of each point in dragging each point which was divided in 10 on the graph in the upper part.
As the interpolation way between at each point on the graph, it chooses "Spline" and "Straight".
When choosing a straight line, because ringing occurs nearby at each point, generally, choose a spline.
When "free wave", use at less than 4410 Hz.

5. "Distortion" view
In the "Distortion view", it generates the corrugation which contained suspected distortion.
It sets the amplitude of vibration(%) of each of the 2nd harmonic, the 3rd harmonic, the 4th harmonic.
The "Total Harmonic Distortion" is displaying RMS ( Root Mean Square ) of each of the harmonics.
The "Clipping level" sets the level(%) which cuts off a corrugation. ( In case of 100 %, it is equivalent to do clipping nothing. )

[ Requirement ]

1. Because it uses an audio output continuously at this app, be careful of the consumption of the battery.

2. This application is usable only in iPhone4 ( iOS later 4.0 ).