Multiple Simultaneous Input Types

The release of APx500 software version 6.0 introduced a new capability: multiple simultaneous input types, or multi-input for short. Multi-input enables the activation of a second input type on any APx modular audio analyzer, or APx515 analyzer, and to make measurements simultaneously on analog and digital signals. With two input types enabled, measurement results are provided for every enabled input channel. The version 6.0 release also added a new derived result, Sensitivity, which displays the RMS Level relationship between the analog and digital inputs (see images below; click to enlarge). This is especially useful for determining the sensitivity of a digital microphone by comparing its RMS level results to those of an analog reference (measurement) mic.

The multi-input feature is available for use in both Sequence Mode and Bench Mode and supports all the essential measurements used for the analysis of microphones and microphone arrays. This includes Transfer Function, a dual-channel FFT analysis function added in release v5.0. With multi-input and Transfer Function, the complex, magnitude and phase, relationship between multiple analog or digital microphones or other cross-domain devices can be found. Additionally, filters and EQ settings can be applied independently for each configured input.

For audio devices that can have both analog and digital outputs active simultaneously, the new multi-input feature enables the simultaneous evaluation of those outputs, whether in a design lab or on a manufacturing line. Measurement consistency can be improved as a result of acquiring the input signals from all input types simultaneously, rather than sequentially. Testing can also be streamlined and sped up by using parallel, rather than multiple sequential, acquisitions to achieve test results.

Developers of devices with digital microphones—smart speakers, mobile phones, Bluetooth® headsets, and other devices—should find the multi-input capability especially useful, as it allows for the simultaneous measurement of the device’s microphone in conjunction with an analog measurement microphone as a reference.

Release 6.0 is compatible with all analyzers in the APx500 Series and is shipping with all new APx analyzers. Multi-input can be configured on all analyzers except the APx511 and the APx500 Flex. An APx KeyBox is required to run v6.0 on Legacy APx analyzers. APx KeyBoxes already installed on Legacy analyzers (for v4.6 and 5.0), are also compatible with v6.0, requiring only an updated license file once an upgrade is purchased.

To see the multi-input capability in action, check out our videos Measuring MEMS Microphones Using APx500 Multi-Input or QuickTip 216 - Simultaneous Multiple Input Types.