APx500 v7.1 — Expanding the Scope of Units of Measure
May 11, 2022
Traditionally, Audio Precision (AP) has been associated with the direct measurement of audio signals in units of Volts or FS (full-scale). In recent years, we have expanded our scope to support acoustic units including Pa and dBSPL (dB relative to 20 μPa). In our latest v7.1 software release, the handling of units of measure is now more integrated, improving the presentation of your input units.
This new measure allows you to scale any input in either the native unit domain of that physical input or in Volts, FS, Pascals, or Amps.
This allows you to do things like:
• Scale an analog to digital converter in Volts according to the Volts/FS ratio of the converter.
• Express the sensitivity of a microphone with a digital output in dBSPL or Pa.
• Measure the voltage across a current sense resistor and express amplitude in terms of current, Amps.
In addition, when scaling the input, the sensitivity or conversion factor is separate from gain or attenuation that may be provided by an external signal conditioner.
The updated control in the APx500 v7.1 software release.
• accounting for the gain of a device (like an external microphone pre-amp) so it is not convolved with the sensitivity of the microphone used.
• expressing amplitude figures correctly when attenuation is introduced externally to test devices like very high-powered amplifiers.
Finally, there are times when using a multichannel audio analyzer that you want to use some input channels, but not all, non-sequentially. With version 7.1 you can now select just the input channels you want to use and order them non-sequentially.