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21 Cards in this Set
- Front
- Back
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SSPL90/ MPO |
Measurements of the upper limit level in a hearing aid directly apply to UCL on the patient |
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What does a line flatter than 45° indicate? |
A form of compression |
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A linear input output curve always..... |
Maintains a 45° slope until the limit of the amplifier is reached |
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When the input sound increases 1 dB then... |
The output changes by one Decibel and the hearing aid has a constant gain |
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T/F
A linear amplifier has a 2:1 relationship |
False It has a 1:1 relationship |
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What determines the saturation output level? |
The entire circuit including the receiver, microphone and battery voltage |
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Linear amplifier |
Amplifies the input sound at a constant rate until the amplifier reaches a natural limit and saturates or overloads causing distortion |
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All amplifiers produce some form of ______________. |
Distortion |
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What does a good amplifier do? |
Makes an accurate, undistorted copy of the input signal from the microphone |
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T/F
Amplifiers maintain the frequency response of the microphone |
True |
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Fidelity |
Reproduction of the signal as accurately as possible |
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What do hybrid circuits do? |
They include more components on the silicone wafer including integrated circuits |
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T/F
Appropriate connections for parts that cannot be built into the circuit or included on the integrated circuit like capacitors, the microphone, battery, volume control and receiver |
True |
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What does an integrated circuit amplifier do? |
Combines dozens of transistors and other components and layers on the tiny wafer of silicone |
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What does coupling do? |
connects one stage in the amplifier to another |
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The amplifier was the largest section of the hearing aid with transistors, capacitors , resistors and switches until the development of what? |
The integrated circuit |
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What do amplifiers do? |
Increase the strength/ intensity of electrical impulses from the microphone |
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What is acoustic Damping? |
A filter placed in the ear hook or earmold tubing on a hearing aid |
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What types of affects do acoustic damping and earmold modifications have? |
smooth out sharp peaks in the frequency response |
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T/F
Most air conduction receivers are internal built into the hearing aid in the behind the ear, in the ear and canal models |
True |
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Resonant frequency |
The frequency where the receiver is most efficient |
