FONIX® 8000 - Frye Electronics

80 FONIX 8000 Hearing Aid Test System
Figure 3.5.2—Comparison of a digital aid tested with Digital Speech ICRA (CRV1), Digital
Speech ANSI (CRV2), and the Composite signal (CRV3).
3.5.3 Testing with Bias Signals
You can add a pure-tone bias signal to the Digital Speech signal, creating a continuous
signal at the frequency of your choice. This will allow you to see how
the aid reacts to the presence of noise at different frequencies. To add a bias signal:
1. Select the DIG SPEECH signal with [F5] in the Coupler screen.
2. Press [MENU] to enter the local menu.
3. Use [, ] to select Bias Tone under Source Settings. Use the [START] key
to skip ahead sections, if necessary.
4. Use [, ] to select the bias amplitude.
5. Press [EXIT] to return to the Coupler screen.
6. Press [START] to start the frequency response measurement. The Digital
Speech signal will include a bias signal at the amplitude you specified in
Step 4.
7. Use [, ] to change the frequency of the bias signal. The current selected
frequency will be displayed on the screen below the Curve Characteristics
Box.
8. Press [STOP] when done with the measurement. See Figure 3.5.3 for an
example of using the bias signal at several different frequencies.