Introduction to the 8000 Hearing Aid
Test System
By: Kristina FryeFrye Electronics, Inc.
Outline Coupler Measurements
Coupler Directional ANSI/IEC Coupler Multicurve Advanced Coupler: Enhanced DSP, Attack &
Release, I/O, Battery Current
Coupler Directional
F3 – Advanced Coupler F5 – Coupler Directional
Directional Measurements
Polar Plot
Difference (0° vs 135°)
Simultaneous, Manual, and Auto Modes In Simultaneous Mode, five polar plot curves are
measured simultaneously A Composite source signal is used to take the
measurements. The response at specified frequencies is graphed
In Manual Mode, the user selects the curve to measure. A Puretone signal at the user specified frequency or a Composite source is used.
In Auto Mode, the user can pre-save manual measurements and run curves automatically
WinCHAP Data Grab
Basic Coupler Measurements
ANSI 03 — F4Coupler Multicurve — F1
ANSI 03 Settings
Choose ear
Aid type
Frequencies Telecoil
ANSI 03 ResultsOSPL90
Response curve
Max
OSPL90-HFA
Distortion
FOG
TelecoilEIN
Battery current
Telecoil I/O curves
Attack & Release
Troubleshooter ANSI
Coupler Multicurve Features
Realistic frequency response measurements
Variety of signal types: Composite, Digital Speech, Pure-tone sweeps
Display 10 different curves simultaneously
Switch back and forth between gain and output. All curves translated.
Coupler Screen Operation
Choose Ear
Select Curve Source Type
Amplitude
Example
50 dB
60 dB
70 dB
80 dB
Troubleshooter Coupler Multicurve
Testing Digital Aids Digital Speech Type of Composite signal Modulated to allow testing of noise
reducing digital aids Used with ANSI or ICRA speech spectra
Example of digital aid test
Digital Speech
Composite
Testing Open Fit Hearing Aids The Open Fit Coupler was designed to
Provide a realistic response for open fit hearing aids.
Provide an easy mechanism for attaching an open fit hearing aid to a coupler
The Open Fit Coupler is a non-standard sized coupler not designed to test to manufacturing specifications
Attaching the Open Fit Coupler
CRV 1 = Open Fit CouplerCRV 2 = HA-1CRV 3 = HA-2 w/attachmentCRV 4 = KEMAR
Coupler Automation Set up own test sequence Select signal type for each curve Select signal amplitude for each curve Add any desired pauses in test sequence Save and auto load test sequence
Programming Auto Mode
F6 — Program Mode
Help window w/instruction
s
F5 — Source TypeAmplitude
START
STOP
Advance to next curve without pause
Advance to next curve with pause
Example of Auto Test
Digital Speech @ 50, 65, 80 dB
Pure-tone sweep @ 90 dB
F6 — Fully Automatic mode
Saving and Loading Settings
Automatically load saved curve group and put analyzer in Auto Mode
Troubleshooter ProfilerGreat for baseline testing… save time!
Advanced Coupler Battery Current [F1] Coupler I/O [F2] Attack & Release [F3] Enhanced DSP [F4]
Function key operations available in the Advanced Coupler Navigation Screen
Battery Current Screen Measure Battery Current as a function of
frequency Measure Battery Current as a function of
amplitude Estimate battery life of hearing aid
Coupler I/O Test Results
Frequency
Test Results
F5: Source Type
Attack & Release Test Screen Visual time graph of Attack and Release
tests Scale graphs independently to zoom in on
results Use Composite or Pure-tone Choose any frequency from 200-8000 Hz
in 100 Hz intervals Customize amplitudes used in tests
Attack & Release Results
Frequency
F5: Source type
F6 & F7: Change graph scales
Enhanced DSP Designed to measure the "group delay" of a
DSP aid. In other words, the actual digital processing time of a hearing aid. 0 ms for analog aids 1-12 ms for DSP Great way to check if aid is analog or DSP
Also tests the "phase" of a hearing aid. This is useful for binaural fittings. Are the aids working together?
Technical Details: Group Delay
An impulse signal is delivered to the hearing aid. The time of the maximum peak of the response is considered the group delay. The 7000 system delay is subtracted from this value to obtain the final measurement.
Technical Details: Phase
One pulse of a 1000 Hz cosine signal is delivered to the aid. This signal is 1 msec long. The first 20 msec of the aid's response to the signal is displayed in graphical format.
ExampleGroup Delay Phase