Chapter 7- Instruments For Studying Waves

Question 0

Acoustical generator

Answer 0

A transducer that produces acoustical disturbances in matter and is therefore a source of sound

Ex) human voice

Question 1

Transducer

Answer 1

Any device which transforms one form of energy into another

Question 2

Acoustical receiver

Answer 2

Detects acoustical disturbances and thus is a receiver of sound

Ex) human ear

Question 3

Two significant categories of transducing devices

Answer 3

Microphones and loudspeakers

Question 4

Piezoelectric effect in transducing devices (hearing aids, earphones)

Answer 4

Mechanical input into electric charge for using distorted materials

Oppositely, electrical voltage is applied to the Crystal changing its shape transforming electrical energy into mechanical energy

Question 5

Capacitive effect

Answer 5

Condenser microphones

Voltage between the parallel plates vary and the mechanical motion of the plates creates a varying electrical signal

Oppositely electrical voltage creates a varying force between the plates creating a varying pressure (electrostatic loudspeakers)

Question 6

Electromagnetic effect

Answer 6

Used in dynamic loudspeakers to convert electrical energy into acoustical energy or in dynamic microphones to convert acoustical energy into electrical energy

Question 7

Dynamic range (of a transducer)

Answer 7

The range of amplitudes over which its output response is nearly linear

Question 8

Microphone

Answer 8

Acoustical energy into electrical energy in the form of a time varying voltage

Question 9

Which two microphones employ the piezoelectric effect

Answer 9

Crystal microphones and ceramic microphones

Question 10

Condenser microphones

Answer 10

Used in applications requiring high precision and wide uniform frequency response. used in research to produce high fidelity recordings and and hearing aids and portable sound equipment. Typically Inc. a preamplifier in the microphone casing

Question 11

Electret condenser microphones

Answer 11

In wide use because they offer the advantages of a condenser microphone without the disadvantage of needing a polarizing voltage

Question 12

Ribbon microphone

Answer 12

Has a very thin metallic ribbon set in the magnetic field. These are used on things like talkshows on the take in sound from one direction

Question 13

Dynamic microphone

Answer 13

Capable of a relatively high power output over a wide dynamic range often use for life performances and recording sessions

Question 14

Loudspeaker

Answer 14

Transducing device which converts electrical energy into acoustical energy

Question 15

“Pickups”

Answer 15

Similar to microphones but do not have diaphragms. Typically use to convert mechanical energy into electrical energy

Question 16

Accelerometer

Answer 16

Device which measures acceleration. Also velocity and displacement

Question 17

Oscilloscope

Answer 17

A useful instrument employed in a wide range of applications to display a time varying voltage on a phosphorescent screen

Question 18

The main components of an oscilloscope

Answer 18

Cathode-ray tube and electrical control circuitry

Question 19

Function generator

Answer 19

A device that provides a variable frequency oscillating voltage corresponding to one or more of the following wave type

Sine, sawtooth, square, triangular, and pulse

Used in conjunction with an oscilloscope to view and study the wave forms of different wave types

Question 20

Spectrum analyzer

Answer 20

A device that converts a waveform into a spectrum to show the amount of each several different frequency sine waves that are present

Question 21

Analog-to-digital conversion

Answer 21

Continuous voltages are sampled to obtain discrete voltages which are then converted into numbers

Question 22

Digital to analog conversion

Answer 22

Converts numbers into discrete voltages which are smoothed into continuous voltages

Question 23

What is an oscilloscope used for?

Answer 23

To view the waveform of a time varying voltage obtained from microphone

Question 24

What is a spectrum analyzer used for

Answer 24

To measure the spectral content of a waveform