Microphone Phase Calibrator (SARACAL™)

The Technology

A number of acoustic sensor applications perform sound location, noise cancellation, beam forming, or other signal-processing functions by taking advantage of the phase relationship of acoustic signals between microphones in an array. SARA has developed a custom test set capable of quickly calibrating an array of microphones for phase and gain vs. frequency. The SARACAL™ Calibrator performs phase-and-gain performance calibration across a selected frequency range for up to 8 microphones simultaneously.

The system generates phase-and-gain vs. frequency plots and data files for use in customer signal-processing software. When connected to a laptop computer, the SARACAL™ provides output files in Microsoft Windows ® format, ready for use in other applications such as Excel ® and MATLAB ®.

Modules are available for standard Gentex microphones or Knowles microphones (with voltage bias). Custom modules can be provided to calibrate microphone/preamp assemblies.

The SARACAL™ Calibrator

The Applications

• Calibrates across the frequencies of interest in applications where phase-delay characteristics are important.
• Calibrates microphone performance vs. frequency and uses the calibration data to compensate signal-processing functions.

The Advantages

• SARA has developed a unique instrument that calibrates microphones on a benchtop in minutes, thus eliminating the arduous process that requires an acoustic generator, support equipment, and hours of testing per microphone array in an anechoic chamber.
• The SARACAL™ overcomes the phase-delay characteristics that vary from microphone to microphone within a production run and that vary as a function of acoustic frequency.