Transfer Function Measurement & APx Software v5.0

With the release APx500 software version 5.0, AP has added transfer function measurement capability, enabling cross-spectral analysis of arbitrary, broadband signals. This makes it an ideal choice for analyzing the frequency response of devices used for speech communication (i.e., smart speakers, smartphones, headset microphones, etc.), as many incorporate DSP algorithms that require the use of speech signals or that block sinusoidal signals altogether.

The transfer function measurement provides the complex frequency response function for a device, including the magnitude and phase (or real and imaginary components), using any broadband signal. This feature, a powerful addition to APx software’s Sequence Mode, allows any APx analyzer to be used as a multichannel dynamic signal analyzer or as a so called dual-channel FFT analyzer. With transfer function and any broadband signal—including speech, music, or noise—APx users can now assess the complex frequency response, coherence, and impulse response of their device or system.

AP’s transfer function provides gapless and overlapped analysis of multiple acquisitions. It also includes a ground-breaking signal-based triggering that eliminates the need for a pilot tone in open-loop test applications, an added benefit when testing “smart” audio devices.

Release 5.0 is now shipping with all new APx audio analyzers, B Series or Legacy, and is compatible with all analyzers in the APx500 Series. An APx KeyBox is required to run v5.0 on Legacy APx analyzers and a KeyBox is shipped with all new Legacy systems. Software licensing, including specialized measurement options, will be tied to a specific analyzer (via serial number) and can now be fulfilled electronically. APx500 software v5.0 requires Windows 10, or Windows 8, 64-bit operating systems.

For further information on the Transfer Function Measurement, check out Technote 138: Transfer Function Measurements with APx500 Audio Analyzers.