Communications Circuits

Question 1

A passive circuit that variably reduces the amplitude or power of a signal without considerably distorting its waveform

Answer 1

Pad/Attenuator

Question 2

What do you call fixed attenuators?

Answer 2

Pads

Question 3

A measure of attenuation introduced by the system in dB

Answer 3

Insertion Loss

Question 4

It represents the ratio of signal level at one point in a circuit to the signal level at another point in a circuit

Answer 4

Decibel Notation

Question 5

The decibel originated as Be is named after

Answer 5

Alexander Graham Bell

Question 6

The impedance which when used to terminate one end of a two-port network will make the impedance seen on the other end equal

Answer 6

Iterative Impedance

Question 7

Adjusting the source/load impedance

Answer 7

Impedance Matching

Question 8

It is a frequency-selective circuit designed to pass some frequencies and reject others

Answer 8

Filters

Question 9

The range of output that have a high output

Answer 9

passband

Question 10

The range of frequencies that are attenuated or rejected

Answer 10

stopband

Question 11

The frequency between a passband and a stopband

Answer 11

cut-off frequency

Question 12

The rate of transition from passband to stopband, and vice versa, is

Answer 12

roll-off rate

Question 13

The frequency at which the output power is 50% of the maximum or the output amplitude is 70.7% of the maximum

Answer 13

cut-off frequency

Question 14

Also known as critical frequency, corner frequency, break frequency, and half-power point frequency

Answer 14

cut-off frequency

Question 15

Composed of only passive components

Answer 15

Passive Filters

Question 16

A filter that provides no amplification

Answer 16

Passive

Question 17

Typically employs RC networks and amplifiers with feedback

Answer 17

Active

Question 18

Termed maximally-flat-magnitude-response filters, optimized for gail flatness in the pass-band and have slow transition.

Answer 18

Butterworth

Question 19

Optimized for maximally-flat time delay

Answer 19

Bessel

Question 20

Designed to have a ripple in the passband, but they have a steeper roll-off after the cut-off frequency

Answer 20

Chebyshev

Question 21

Has an almost perfect frequency response but has variations on both the passband and stopband

Answer 21

Elliptic

Question 22

Passes freuencies below the cut-off frequency and attenuated those above

Answer 22

Low-Pass Filter

Question 23

Passes Frequencies above critical frequency but rejects those below

Answer 23

High-Pass Filter

Question 23

Passes only frequencies in a narrow range between the upper and lower cut-off

Answer 23

Bandpass Filter

Question 24

Rejects or stops frequencies in a narrow range but passes others.

Answer 24

Bandstop Filter

Question 25

It is the ratio between the frequencies at two signals

Answer 25

Interval

Question 26

The condition in an AC circuit where Xl equals Xc

Answer 26

Resonance

Question 27

It is the basis of all transmitters, receiver, and antenna operation.

Answer 27

Resonant Circuits

Question 28

Minimum impedance and maximum current happens at

Answer 28

Series resonance

Question 29

The exchange of energy between the inductor and the capacitor

Answer 29

Flywheel effect

Question 30

What is the primary purpose of the parallel tuned circuits?

Answer 30

To form a complete AC sine wave output as it produced damped sine wave at resonant frequency.

Question 31

Maximum Impedance and minimum current

Answer 31

Parallel Resonance

Question 32

The ratio of the reactive power to the true power

Answer 32

Quality factor

Question 33

A measure of the band pass filter's selectivity

Answer 33

Quality Factor

Question 33

Amplify only a relatively narrow portion of the spectrum, attenuating all other frequencies.

Answer 33

RF Amplifiers

Question 34

What is the fundamental difference between the AF and RF amplifier?

Answer 34

The band of frequencies they are expected to amplify.

Question 35

The first stage of an amplifying system showed a low-noise type because all following stages will be amplifying any noise that the system generates.

Answer 35

Power Amplifiers

Question 36

is biased so that it conducts continuously for 360° of an input sine wave

Answer 36

Class A

Question 37

In class A amplifiers, bias is set so that the output ______

Answer 37

never saturates of cuts-off

Question 38

used primarily as small-signal voltage amplifiers or for low-power amplifiers.

Answer 38

Class A amplifier

Question 39

biased near cut-off

Answer 39

Class AB

Question 40

used primarily in push-pull amplifiers

Answer 40

Class AB

Question 41

biased at cut-off and conducts only one-half of the sine wave input

Answer 41

Class B

Question 42

Normally connected in a push-pull arrangement so that both positive and negative alternations of the input are amplified simultaneously

Answer 42

Class B

Question 43

The _______ amplifier, being the most efficient, makes a good power amplifier

Answer 43

Class C

Question 43

An amplifier whose output conducts load current during less than one-half cycle of an input sine wave

Answer 43

Class C