Term
| Device that replaces a small low-energy signal with a matching high-energy signal |
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Definition
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Term
| An amplifier is an electrical instrument that changes the ___ (usually increases) of the signal fed at its input, while keeping all other characteristics of the signal like phase and shape ___. Thus, it only ___ the energy of the signal without changing its information content |
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Definition
| amplitude; intact; boosts |
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Term
| When does Edison invent the incandescent light bulb? |
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Definition
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Term
Edison invents the incandescent light bulb:
-Conducting filament mounted in a glass bulb from which air had been ___ using a vacuum
-Edison found that he could measure the flow of electrons through the ___ from the filament to a metal plate inside the bulb |
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Definition
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Term
| When does John A. Fleming develop the diode vacuum tube? |
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Definition
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Term
Diode Vacuum Tube:
-Tube containing two electrodes (___ and ___), causing electrons to flow in one direction
-“The measure of amplification of a signal is called the ___ ___ or just ___ and is denoted by the letter A.”
-The gain A “of an amplifier is simply defined as the ratio of the amplitude of the ___ signal to the amplitude of the ___ signal.” |
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Definition
| anode and cathode; amplifier gain; gain; output; input |
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Term
| When does the scientist Lee De Forest invents the triode or audion? |
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Definition
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Term
American scientist Lee De Forest invents the “triode” or “audion":
-Added a ___ electrode to the diode tube
-Making small voltage changes at the 3rd electrode (grid) caused large changes in voltage at the ___ (plate)
-This was the first ___ amplifier |
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Definition
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Term
Vacuum tube amplifiers:
-For ___ years this powered all amplifiers
-vacuum tubes are very ___ and get very ___
-Also ___ |
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Definition
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Term
-A vacuum tube is composed of a cylindrical glass tube consisting of a ___ filament, a ___ ___, and an ___ plate placed in a vacuum
-The filament “is heated using an external source causing it to emit ___ into the vacuum forming an ___ ___. The plate (anode) has a very high ___ potential to attract the electrons emitted by the filament. |
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Definition
| cathode; control grid; anode; electrons; electron cloud; positive |
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Term
Vacuum Tube:
The controlling action (like a volume control) is performed by the ___ ___. The grid is a thin metallic mesh placed very close to the plate so that it can ___ the electrons collected by the plate. The low voltage input signal to be amplified is connected to the ___. This changes the electric field around the grid as per the input signal and modulates the flow of electrons from the ___ to the plate. As the input signal is used to modulate the flow of electrons in the tube, the output signal taken from the plate is an ___ version of the input signal. Vacuum tubes are ___, inexpensive, and provide better ___ for high power applications like radar, television transmission, and so forth. However they are ___ and need extra power to ___ up the filament. This makes it impractical for use in low power applications where there are power supply and ___ constraints. Bipolar junction ___ are used for this purpose |
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Definition
| control grid; influence; grid; filament; amplified; robust; amplification; bulky; heat; space; transistors |
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Term
| When did Bell Laboratories invent the transistor? |
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Definition
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Term
Transistors invented at Bell Laboratories:
-Studied behavior of electrons when ___ and ___ materials were placed very close together
-Amplified like vacuum tubes (small voltage increase at one contact caused large voltage increase at a second contact) but did not produce wasted ___ or take time to “___ ___” for use |
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Definition
| metal; semiconductor; heat; warm up |
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Term
| Bipolar junction transistor (BJT) commonly known as a transistor is a 3-terminal semiconductor device capable of controlling the ___ of current that flows through it. BJTs are ___ and consume less ___ because they do not require an external heating supply for operation as do vacuum tubes. They are made of ___ crystals and are sturdy components with a size comparable to ___ and___. This makes it possible to implement it in a circuit. |
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Definition
| flow; small; power; semiconductor; resistors; capacitors; |
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Term
| Millions of transistors can also be fabricated onto small ___ that can be used as switching devices. Thus, almost every modern day ___ device uses many transistors for multiple applications. |
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Definition
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Term
-Transistors extract power from ___ voltage sources and apply that power to ___ signals
-The ___ of the DC source determines how much current is allowed to flow across the transistor from the AC signal source to the receiver of the AC voltage
-Transistors are the ___ for all modern “steady-state” electronics
-___ element of computers, audiometers, mobile telephones, and all other communications equipment |
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Definition
| DC; AC; voltage; basis; Fundamental |
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Term
Amplifier:
-Input circuit from the acoustic transducer (i.e., ___) passes through the amplifier
-Output circuit generated by the ___ supply of the amplifier (i.e., battery or electric power supply converted to DC)
-Amplifier applies a varying ___ to the output circuit which mimics the voltage changes in the input circuit |
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Definition
| microphone; power; resistance |
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Term
| how much the volume is being turned up |
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Definition
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Term
Amplifier characteristics:
-The ___ ___ is the ratio of the input signal to the output signal of an amplifier
-The ___ ___ is he range, usually expressed in dB, between the smallest and largest functional output levels of the amplifier |
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Definition
| transfer function; dynamic range |
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Term
| ___ is the magnitude of the transfer function, usually expressed in dB |
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Definition
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Term
Amplifier Characteristics:
-___ is the relation between input and output signals as a function of input amplitude
-The ___ ___ is the relation between an input signal and an
output signal as a function of signal frequency and amplitude |
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Definition
| linearity; frequency response |
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Term
| HA are designed to be ___ after a certain amplitude so it doesn't damage the patient's hearing further |
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Definition
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Term
Amplifier Characteristics:
The ___ is the precision of the reproduction of input signal
characteristics in the output signal
-___ ___ means high quality reproduction of sound by an amplifier or amplifying system |
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Definition
| Fidelity; high fidelity (Hi-Fi) |
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Term
Distortion: amplification...
-which is not ___
-in which part of the ___ signal is lost
-and/or in which the output signal contains energy not present in the ___ waveform |
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Definition
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Term
| Circuit used to reduce voltage amplitude within a specified frequency range |
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Definition
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Term
Attenuators generally consist of networks of ___ that are
taken in and out of the circuit by switches, allowing the signal to be attenuated incrementally |
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Definition
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Term
| Signal processing device or function that shapes a signal by removing unwanted components or enhancing desired components |
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Definition
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Term
| the selective elimination of noise outside of the frequency range of a desired response |
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Definition
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Term
| Reduces the amplitude of signals above the cutoff frequency |
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Definition
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Term
| Low pass filters may be used to eliminate high-frequency ___ or ___ ("hiss filter) |
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Definition
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Term
| Reduces the amplitude of signals below the cutoff frequency |
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Definition
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Term
| High-pass filters may be used to eliminate low-frequency ___ ("rumble filter") |
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Definition
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Term
| Reduces the amplitude of signals above and below two cutoff frequencies |
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Definition
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Term
| Band-pass filters are a combination of ___ filter and ___ filter. This is how we get ___ noise. |
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Definition
| high-pass; low-pass; narrowband |
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Term
| Reduces the amplitude of signals between two cutoff frequencies |
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Definition
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Term
| Band-reject filter may be used to eliminate ___. Sometime called a ___ filter or ___ filter |
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Definition
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Term
Filter characteristics:
-___: the frequency above which (or below which) energy is attenuated
-____: the rate of attenuation below (or above) the kneepoint, usually expressed as a function of dB/octave or dB/Hz
[image] |
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Definition
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Term
Filter Characteristics:
-___: the range between the lower and upper half power point
-___-___ ___: the frequency at which output power has dropped to 50% (i.e., a 3 dB decrease) of its level at the middle of the band |
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Definition
| Bandwidth; Half-Power Point |
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Term
-High-pass and low- pass filters have ___ half-power point
-Band-pass and notch filters have ___ half-power points |
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Definition
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Term
[image]
1. What type of filter is this?
2. Where is the filter's kneepoint?
3. What is the approximate roll-off rate of this filter (in dB/octave)?
4. Where is the half-power point of this filter? |
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Definition
1. low-pass
2. 32,000 Hz
3. 3 dB/octave
4. 64 kHz |
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Term
Speakers:
-Inverse of a ___
-Converts ___ energy to ___ energy |
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Definition
| microphone; electric; acoustic |
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Term
Speakers:
-Electromagnetic devices that convert a ___ into ___ energy (sound)
-Generally consist of one or more ___ housed in an
enclosure. For high-fidelity sound, multiple drivers for different ___ ranges are required
-Important element of sound array – ultimate the quality of a sound output is a function of ___ performance |
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Definition
| voltage; acoustical; drivers; frequency; speaker |
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Term
| What are the components of a driver? |
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Definition
A diaphram, suspension, voice coil, and a magnet
[image] |
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Term
| lightweight, thin diaphragm connected to a wire coil in a flexible suspension |
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Definition
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Term
Driver:
When electrical current passes through the coil, it becomes an ___, generating a mechanical force that moves the coil (and attached diaphragm) ___ and ___ in response to the signal |
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Definition
| electromagnet; back and forth |
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Term
-The driver diaphragm produces sound waves via ___ movement (reverse of microphone diaphragm action)
-The diaphragm is supported by a cone that is usually made of ___ or thick ___, that vibrates ___, and is suspended at the ___ end |
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Definition
| oscillatory; plastic; paper; rapidly; wide |
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Term
-The voice coil of the driver is an ___ wire coil
-The coil is an output signal (to the speaker) that constantly ___ the flow of electricity
-The coil moves back and forth over the magnet and it creates oscillating motion of the ___
-It is supported by a spider, which is a round, tensed piece of fabric that ___ and holds the ___ ___ in place, and during vibration it exerts force to return the coil in ___ position |
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Definition
| electromagnetic; reverses; diaphragm; pleats; wire coil; resting |
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Term
Type of drivers:
-“___” – very low frequencies
– “___” – low frequencies
– “___” – middle frequencies
– “___” – high frequencies |
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Definition
| subwoofers; woofers; squawkers; tweeters |
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Term
Speaker classifications:
-Driver ___
-___ of drivers
-___-SPL produced by a 1 watt input at a distance of 1 meter from the diaphram
-___ ___-The highest output SPL a speaker can handle before it is damaged
-___ ___(based on max SPL)-The continuous and peak power levels a loudspeaker can handle before it is damaged |
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Definition
| type; Number; Sensitivity; maximum SPL; Rated power |
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Term
| total electrical load of inductors and capacitors in the speaker array |
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Definition
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Term
Speaker Classifications:
___ is the resistance plus reactance of the speaker
-Impedance is how much power it takes to ___ the speaker
-Impedance is an essential measure of ___ with the amplifier driving the speaker(s) |
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Definition
| impedance; drive; compatibility |
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Term
-Low impedance speakers require ___ current and may ___ the amplifier
-High impedance speakers require ___ current but produce ___-___ output
-Most commercial speakers have impedance in the range of __-__ Ohms |
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Definition
| more; overstress; less; low-intensity; 6-8 |
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Term
-impedance needs to ___ the amplifier. So low impedance needs a ___ amplifier output.
-no circuit has a 100% flow-theres always some loss of ___ |
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Definition
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Term
There are 3 elements of frequency response:
-frequency range (ideally as ___ as possible)
-Amplitude as a function of ___ (ideally as ___ as possible)
-Response time of the speaker ___ (ideally as ___ as possible). how quickly the diaphram comes to ___. Want this to be as short as possible so that the ___ sound doesn't affect the following sound. |
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Definition
| wide; frequency; flat; cone; short; rest; previous |
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Term
| Headphones are a small ___ |
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Definition
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Term
-Supra-aural headphones have high ___ and low ___
-Nearly ___ frequency response
-if you want to develop an audiometer that consistently produces tones in frequ. and intensity you need to take into account the difference between ___ and ___ for the headphones and for the individual |
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Definition
| sensitivity; distortion; flat; SPL; HL |
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Term
-Circumaural headphones do not have as much of a ___ drop off as the supra-aural headphones
-When fit properly, the cushion entirely encloses the ___
-Used to test hearing above ___ Hz |
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Definition
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Term
-___ headphones are should-mounted transducer coupled
to the ear canal by a sound tube and foam insert headphone tip
-frequency response is ___
-can produce falsely ___ thresholds when the TM is perforated but other than that inserts are ___. |
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Definition
| Insert; flat; low; favorable |
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Term
Other speakers in audiometry:
-___ ___ and ___ stimulus generators in immittance bridge
-___/___ generators in OAE equipment
-___/___ generators in evoked response equipment. Frequently a standard audiometric transducer, such as an ___ earphone |
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Definition
| Probe tone; reflex; tone/click; tone/click; insert |
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Term
-Audiometers use amplifiers and filters to generate ___ ___, and microphones and loudspeakers to present them
-Immittance bridges use loudspeakers to generate the ___ ___ and microphones to ___ the response
-Hearing aid test boxes use all of these components to evaluate hearing aid ___
-___ ___ themselves contain all of these pieces as well |
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Definition
| test signals; probe tone; measure; function; Hearing aids |
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