Signal generator 1.0.2

• Outputs sine, pink noise, and white noise
• Volume and frequency sliders
  • Controls are hard to grab at the edges
  • Volume control is independent from the phone’s volume control
  • Doesn’t go below 100 Hz
• Sine waves are distorted and badly aliased at high frequencies.  THD+N measurements:
  • 100 Hz 0.149%
  • 1 kHz: 0.08%
  • 10 kHz: 7.1%
  • 20 kHz: 20.15%
  • Spectrum for 997 Hz:
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• Although the control says “1.00 kHz” at startup, it’s actually playing 765 Hz.  Frequencies are correct after you start moving it around, though.
• White noise level is higher than sine wave — sine wave never reaches the peak output of the phone, even at “0 dB”
• There doesn’t seem to be any way to enter levels other than 0 dB manually, since it doesn’t let you type a minus sign.
• White noise sounds like it’s repeating every 1.4 seconds
• Noise is the same in both channels

Frequency generator 200909150

• Outputs sine, square, triangle, sawtooth
• Playing more than one sine wave causes clipping, but you can decrease the phone’s volume control
• Default setting is 440, 444, and 448 Hz, but when played together, the waveform changes abruptly once per second
• Sine wave THD+N:
  • 40 Hz: 1.00%
  • 440 Hz: 0.056%
  • 10 kHz: 0.051%
  • 20 kHz: 0.222%
• I don’t know how the square, triangle and sawtooth are generated, but it ain’t right.
  • This is what the “square wave” looks like at 10 kHz:
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  • And this is the spectrum:
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  • Nooot even close

(Using ExtUSB headphone cable, Adobe Audition, Audio Precision.)