The LD-DPS provides fast and accurate DPOAE measurements in a compact and portable form factor.

The device uses the adaptive modeling of both the DPOAE recording channels and the interference/noise channels to extract real time DPOAE signals. It employs dedicated sensors for noise modelling.  With this signal processing and data acquisition, the system can efficiently filter out the in-band noise and track the DPOAE suppression in real time. The system has achieved higher tracking speeds and accuracy than the Kalman Filter based real-time DPOAE measurement.   


  • Integrated Design:
    • The Data Acquisition box includes all the necessary hardware for DPOAE suppression testing in a single unit
    • Wideband, low noise, low distortion amplifiers for probe microphones and speakers
    • ADC: 4 channels, 24bits, sampling rate-93,750 Hz.
    • DAC: 4 channels, 24bits, sampling rate-93,750 Hz.
    • Primary tone generators, suppressor stimuli generators.
    • Built-in medical grade isolator for noise reduction and electrical safety.
    • High speed USB 2.0.
  • Dual probe configuration:
    • Each probe can function as a DPOAE probe and/or as a suppressor probe. The software configures the probe functions automatically based on test tasks.
  • DP-Gram, IO-Gram test options:
    • F1,F2 :0.2 KHz to 16 KHz, user settable F2/F1 ratio
    • L1,L2: 30 to 85 dBSPL
  • SP-Gram (Suppression Gram) test:
    • Real-time DPOAE as well as synchronized running average.
    • Suppressor configuration:
      • Contra-lateral
      • Ipsi-lateral (optional, under development).
    • Suppressor type:
      • Gaussian white noise
      • Narrow band noise (optional, under development)
      • Pure-tones (optional, under development).
    • Suppressor control: configurable ON-OFF time, Period and level.
    • Synchronized running average: configurable artefacts rejection
    • Time resolution: 0.8 (ms)
  • Database and other support software:
    • DP-Gram, IO-Gram test records:
      • Subject info
      • Test protocols
      • Test Results
    • SP-Gram (Suppression Gram) test records:
      • Subject info
      • Test Protocols
      • Synch Average results and raw Suppression Gram data
    • Utility program functions:
      • Export database data to MS Excel file
      • Post processing of raw Suppression Gram data
        • Allow replay of recorded real-time DPOAE
        • Allow offline re-processing of the recorded real-time SP data with user configurable settings.
        • Multiple view of test data: graph view and table view.
      • Easy to use GUI – many functions are self-explained through labeling and can be done with a single mouse click.


For details of the DSP algorithms please refer LD-DPS DSP Algorithms , for how to use the system, please see the video below.

Narrated Instructional Video