SignalScope for iPhone OS devices is a real-time analysis toolset, suitable for use in areas such as acoustics, audio, electronics, and vibration. Out of the box, SignalScope includes an FFT-based spectrum analyzer and an oscilloscope. Additional tools, including a level meter, octave and 1/3-octave spectrum analyzer (RTA), and a signal generator are available via in-app purchase. Alternatively, it is possible to upgrade SignalScope to the full functionality of SignalScope Pro via in-app purchase.
Another upgrade via in-app purchase enables SignalScope to turn your iPhone or iPod touch into a platform for data acquisition, storing acquired data in tab-delimited text files or MAT-files for later retrieval from your device. Capturing plots as images to your photo library is included out of the box.
Input signals can be acquired from the built-in accelerometer, or from the current audio input path (the iPhone OS automatically selects the audio input path according to which external audio devices, if any, are connected to your device). Units, including Pa (pascals) and FS can be assigned to input channels of the dock connector audio input or the headset input (not available on 1st generation iPod touch devices). Sensitivity calibration can also be performed for any audio input device or input channel.
The data acquisition upgrade enables additional signal units, including Volts, Amps, g's, and ips (inches per second). (g's are always enabled for the built-in accelerometer.)
“Touch” your data with highly interactive, multi-touch enabled analyzer displays.
NOTE: The frequency response of the iPhone's built-in and headset microphones is quite flat. However, the built-in microphone of the original iPhone seems to be routed through a codec, which limits the sample rate to 8 kHz and significantly affects the frequency response. The iPhone 3G rolls off the built-in and headset mic signals below 100 Hz. Those interested in further discussion regarding iPhone microphones are invited to visit the forums.
NOTE: 3rd generation, or older, iPod touch devices require additional external hardware to get audio signals into SignalScope, due to the lack of a built-in microphone.