Chapter 15

Front 1

Digital to analog conversion

Back 1

The results of the processing algorithm which is still a series of numbers is converted back into an analog real - world signal

Front 2

Hybrid

Back 2

Merging of two types of technologies

Front 3

T/F
Regardless of the sampling and bit rates used, the performance and frequency limits with digital hearing instruments will be limited by the transducer( ie. microphones and receivers)

Back 3

True

Front 4

What are the 2 processes involved in analog / digital conversion?

Back 4

Sampling and quantization

Front 5

What is a digital memory used for?

Back 5

To store the hearing instrument parameter settings.

Front 6

Analog

Back 6

Data in the form of continuously changing quantities

Front 7

Hipro

Back 7

Hearing aid connects to the PC interface through a cable with a special battery pill that is put into the battery compartment or with a subminiature plug inserted into a socket on the hearing instrument

Front 8

What is the voltage used in HA batteries?

Back 8

1.3 volts

Front 9

How much does each bit contribute to the dynamic range?

Back 9

Approximately 6db

Front 10

Class 1

Back 10

Single channel / single memory

Front 11

NOAH

Back 11

Common software platform for multiple brands of programmable hearing instruments , allowing dispensers to use a PC to fit a variety of hearing instruments with one system

Front 12

Aliasing

Back 12

A type of error when a frequency component higher than the nyquist frequency is sampled audible as distortion

Front 13

Class 2

Back 13

Single channel multiple memories

Front 14

Images

Back 14

Erroneous high frequency components that occur at values above the nyquist frequency

Front 15

Prom

Back 15

Programmable read only memory

Front 16

Anti-aliasing filter

Back 16

A filter placed prior to the a/d converter to prohibit introduction of frequency components higher than the nyquist frequency

Front 17

Nyquist Theorem

Back 17

Basic rule of digital sampling that says the sampling rate must be at least twice as fast as the highest frequency that is desired in the signal processing

Front 18

What are the different types of storage mechanisms in semiconductor memory?

Back 18

Ram (random access memory)
Prom(programmable reado only memory)
Eprom(erasable programmable read only memory)
Eeprom(electrical erasable programmable read only memory)

Front 19

Pre- amp

Back 19

Following the microphone a form of amplification applied to a signal usuall 10-15 DB

Front 20

Direct digital drive

Back 20

Digital signal is passed directly from the DSP to a digital output driver and to the receiver, for both the low pass filtering and demodulation into an audible analog signal

Front 21

How does EPROM allow the parameters to be programmed?

Back 21

Programmed parameters can be changed after exposing the digital memory to an ultra violet light in order to erase it

Front 22

A/D converter considered the best technique for use in digital / audio products

Back 22

Sigma- delta converter

Front 23

Example of a hybrid instrument

Back 23

Zeta noise blocker
DCA digitally controlled analog

Front 24

T/F
Any instrument that is not a "truly " or "fully" digital hearing instrument is an analog hearing instrument

Back 24

True

Front 25

T/F
In a digital HI with a sampling rate of 16khz the instantaneous value of the sine wave is measured 16,000 times per second

Back 25

True

Front 26

Three basic stages of a digital system

Back 26

Analog to digital conversion
Processing algorithm
Digital to analog conversion

Front 27

RAM

Back 27

Can have data written to and read from it in any random order but needs a second back up voltage supply to store the programmed parameters

Front 28

Signal Processor

Back 28

Highly optimized microprocessor that performs mathematical steps thousands of times a second

Front 29

Algorithm

Back 29

A list of rules / instructions for processing a signal

Front 30

EEPROM

Back 30

Electrical erasable programmable read only memory

Front 31

Class 4

Back 31

Multiple memories / multiple channels

Front 32

Number of bits

Back 32

"Word with" tells you the amplitude resolution / amplitude detail of the signal also impacts the dynamic range

Front 33

EPROM

Back 33

Erasable programmable read only memory

Front 34

Prom

Back 34

Parameters can be started only once requiring a physical change in the prom chip to change hearing instrument performance

Front 35

What are some of the advantages of digital sound processing

Back 35

*Lower noise higher fidelity

*Extensive programming capability

The ability to load a variety of processing schemes into one HA using software

Front 36

T/F
When a 1 is placed at the end of a number string the number is doubled

Back 36

FALSE - when a zero is placed at the end the number is doubled

Front 37

Most common analog signal

Back 37

Sine wave

Front 38

Hybrid analog - digital hearing instrument

Back 38

An instrument with a digital chip to control some aspect of how sound is amplified

Front 39

Binary number

Back 39

A number that consists of the numbers 0 and 1

Front 40

T/F
DIgital signals can be manipulated with greater precision and reliability and less additive noise compared to analog processing

Back 40

True

Front 41

What is the sole reason for the analog to digit conversion process

Back 41

To transform the signal into a useable form for the processor

Front 42

Microphone

Back 42

To convert incoming sound into an electrical current

Front 43

T/f the addition of a zero at the end of a decimal system number means a multiplication of 10

Back 43

True

Front 44

Analog electrical system

Back 44

Voltage levels increase and decrease continuously over time.

Front 45

Processing algorithm

Back 45

A set of mathematic steps involving addition, subtraction combined in a comples sequences

Front 46

Nyquist frequency

Back 46

One half the sampling rate