MODULATION AND CODING TECHNIQUES

Multiplexing

When two or more signals share a common channel, it is called:

Time-Division Multiplexing

TDM stands for.

the power in the outer sidebands is negligible

The bandwidth of an FM signal is considered to be limited because

• Creation of harmonics baseband frequencies

• Baseband frequencies “mixing” with each other

• Shift in phase relationships between baseband frequencies

Distortion is caused by;

• The sender

• The receiver

• The channel

Noise in a communication system originates in

Its amplitude, frequency, and phase angle

The part or parts of a sinusoidal carrier that can be modulated are:

• Audio

• Video

• Digital data

The type of information that can be sent using AM is:

Morse Code

The first digital code was the:

A regenerative repeater

In digital transmission, signal degradation can removed using:

• PDM

• PWM

• PPM

  (PPS is not pulse modulation technique)

What are the pulse modulation technique?

I=ktB

Hartley’s Law is:

Duplex

Method of telecommunications operation where transmission can be made simultaneously in both direction of a channel.

Digital, analog

Communication through the use of a modem, is transmission of data information in medium.

Bandwidth

A term used in radio communication defining the frequency band from the lowest to its highest limits, designed to be passed through a component, system or a device with an accepted attenuation

ITU-T

What are body in the present ITU structure took the place of CCITT?

Bits are transferred simultaneously

Why parallel transfer method in data transmission faster than serial?

Baseband

In data transmission technology, signals such as a voice, video are binary transmitted over a cable known as ____signals

Modulation

What is the process in radio communication where information or intelligence signal at lower frequency is put unto higher radio frequency for transmission to receiving station

Analog

Transmission of information through a communication modem is intended to transmit digital information over which of the following type of communications medium.

Bandwidth

In basic transmitter such as CW transmission, the rounding off square wave emission will reduce _____.

• Begins with PAM

• Is a coding system

• Does not transmit the actual signal that is the input

PCM

PCM

What is the easiest type of system to use for secure (encrypted) computer communications?

• In wide use throughout the world

• The key to the telephone expansion that has occurred since 1920’s

• Not ideal for data transmission but usable

Frequency division multiplexing is

Nothing

What can you hear from radio transmitting station without modulation over a radio receiver tune to the same frequency?

To reshape the pulses after they have become distorted

What is the function of a regenerative repeater?

The approximation of the quantized signal

What causes quantization noise of PCM system?

• A BCD code

• An eight-bit cod

• Used in IBM system 360 and 370

What is EBCDIC

Modulation

A process which occur in the transmitter part of the transceiver.

Half Duplex

Mode of communication system where both sides of the system wait for their turn to transmit at a time.

communication medium

What causes the signal to be attenuated?

QAM

The digital information is contained in both the amplitude and phase of the modulated carrier.

Channel capacity

_______ is defined to be the maximum rate at which information can be transmitted through a channel.

Pulse

In ______ modulation the carrier is a periodic rain pulses.

Pulse code modulation

Which of the following pulse modulation techniques is a digital transmission system?

Shannon-Hartley theorem

Which theorem sets the limit on the maximum capacity of a channel with a given noise level?

Sampling, quantizing and coding

What are the steps to follow to produce a PCM signal?

Full duplex

All bits in a character can be sent / received simultaneously.

Agreed upon in advance between sender and receiver

Codes must be:

3.32

One dit is equal to ____ bits.

ASCII

What is the most widely used data communications code?

1 and 0

Mark and space refer respectively to

Muldex

What is the device that contains both a digital multiplexer and a demultiplexer?

TDM

Multiplexing scheme used by baseband transmission

FSK

Which of the following is not commonly used modem modulation