Term
-Talker wears ___
-Transmitter has a ___
-Microphone should be within ___ inches of the speaker's mouth |
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Definition
| transmitter; microphone; 6 |
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Term
| What is the absorption coefficient? |
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Definition
| How much an object or environment absorbs or reflects sound. It is on a scale from 0-1. 0 being completely reflective and 1 being completely absorptive |
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Term
Short-Range Radio-frequency Transmission:
-In general, the carrier frequency is a ___ ___ until the audio-electrical signal ___ the carrier frequency. The carrier does not convey a message unless it has been ___ by an audio-signal |
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Definition
| sine wave; modifies; modified |
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Term
| What are the two types of modulation most common with hearing aids? |
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Definition
| frequency and amplitude modulation |
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Term
-Transmitters are able to "talk" to receivers when tuned to the same ___ frequency
-Licensing authorities set certain bands of the ___ spectrum for certain purposes
-____ ____: are narrow frequency ranges that contain a number of designated frequencies for special purposes. The frequency bands available for hearing aids are: 37, 43, 72-76, 173, 183, 216, 900, and 240 MHz.
-When there are more than one transmitter on the same frequency band, the transmitter has a tendency to demodulate only the strongest signal which is called the ___ ___ effect |
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Definition
| carrier; elctromagnetic; Transmission channels; FM capture |
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Term
| Digital modulation techniques is accomplished by differential binaural phase-shift keying which occurs when the 1's and 0's of the digital data are represented by the phase of the ___ ___ carrier |
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Definition
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Term
Example of differential binaural phase-shift keying:
-Every time a "1" occurs, the phase of the carrier shifts by ___ degrees
-Every time a "0" occurs, the phase remains ___ |
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Definition
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Term
| Frequency-hopping spread spectrum: is used by ___ technology and occurs when the transmitter changes the carrier frequency by hopping between ___ channels (each 1 MHz wide) ___ times per second between 2402 to 2480 MHz. When a frequency has interference, the transmitter and receiver skip it, which is called ___ ___ ___. |
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Definition
| Bluetooth; 79; 1600X; adaptive frequency hopping |
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Term
Bluetooth technology...
-Limited to __ feet or __ m
-Used for specific ____, like NOAH-link devices
-Disadvantages?
-New standard of ___-powered bluetooth has been developed |
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Definition
| 30; 10; applications; Too much drain on the batter to be place into hearing aids. Too much audio-delay.; low |
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Term
Hardwire such as direct-audio input:
-Advantages:
1. Provides a _______ signal
2. ___-operated switches and adaptive systems are most easily possible
3. ___ is possible
-Disadvantages:
1. ___ convenient
2. Cosmetically ___
3. Less ___ after longtime use |
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Definition
| well-defined; Speech; Stereo; Less; undesirable; reliable |
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Term
Teleloop:
-Advantages:
1. Better ___ appeal (especially for teens)
2. ___ connection
-Disadvantages:
1. Low frequencies can be ___
2. Signal can be attenuated when the head is ___________
3. Signal may experience interference from ____ ___ |
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Definition
| cosmetic; Cordless; attenuated; tilted to either side; electrical sources |
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Term
Silhouette:
-Advantages
1. A ___ connection is possible
2. No change in signal strength with ___ ___
-Disadvantages
1. ___ frequencies can be attenuated
2. Signal may experience interference from ___ ___ |
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Definition
| stereo; head position Low; electrical sources |
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Term
-FM receiver to or in HA: best option is when the coupling occurs ___ the HA or snaps into the aid with a ___ or ___
-Advantages
1. Best ___
2. ____ appeal (no ___!)
-Disadvantages
1. Digital signal processing in HAs can cause interference in a ___ wireless receiver |
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Definition
| inside; shoe or boot; reliability; Cosemetic; wires; nearby |
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Term
Listeners with Hearing Aids and FM Receivers:
-2 microphones:
1. ___ microphone: is the HA microphone
2. ____ microphone: is the mic that picks up the speakers voice
-Problems can occur because the HA mic may pick up ___ sounds that may ___ the speaker's voice
-The problem may be solved by mixing the 2 signals and emphasizing the FM signal which is called FM ____, FM ____, and FM ____
-Children tend to prefer both mics to be ___ because they fell "cut-off" by the environment if they hear the FM mic only |
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Definition
| Local; Transmitter; environmental; mask; FM priority, FM advantage, or FM precedence; equal |
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Term
| The problem with the HA mic picking up environmental sounds that may mask the speaker's voice can be solved by having an automatic switch in the FM system that attenuates the ___ mic when someone speaks into the FM mic. The local mic is unattenuated when there is no input to the ___ mic. This is known as ____-___ switching or ___-___ switching. |
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Definition
| local; FM; speech-operated switching (SOX); voice-operated switching (VOX) |
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Term
| ____ ___ is another solution to this problem and with it, the degree of FM advantage automatically increases as the level of background noise increases, improving speech recognition in noise |
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Definition
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Term
How important is classroom listening?
-___ of a student's day consists of listening to and participating in spoken communication
-Listening environments need to be free of acoustic and non-acoustic ___ |
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Definition
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Term
| Communication in the classroom can be difficult because of what 3 factors? |
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Definition
| noise, reverberation, and distance |
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Term
| What are some results of poor acoustics on kids in school? |
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Definition
| poor performance on cognitive tasks, poor readings skills, poor math skills, and poor attention and on-task behavior |
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Term
-Reverberation occurs when sound encounters a ___ ___
-Sound ___ around a room
-The effect of reverberation is ___ of speech as you move away from the talker
-Normal listeners do best when reverberation times are below ___ seconds |
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Definition
| hard wall; bounces slurring; .6 |
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Term
Problems in the classroom:
-As talker moves from the listener the signal decreases __ dB every time the distance is doubled
-Noise is usually the biggest problem
1. At the back of a typical classroom with no children present, the signal-to-noise ratio (SNR) would be ___ dB
2. With children present, the background noise is going to be at least __ dB, resulting in a SNR of about __ dB |
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Definition
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Term
When noise, distance, and reverberation are combined the result is speech is difficult to understand:
-For normal listeners a +6 dB SNR leads to a ___% decrement in speech recognition
-When a reverberation time of .7 sec is combined with a SNR of +6 dB WRS decrease by as much as ___%
-A student at the ___ of the room has a disadvantage |
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Definition
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Term
| A study to demonstrate the overall effect.... |
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Definition
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