What is the function of OTDR

 i) OTDR detects faults going in the optical fiber       link.

 ii) Fast automatic testing.

 iii) Troubleshoot the faults in optical fiber                   communication.

iv) Maintain optical telecommunication network.

Requirements of rectifiers

Rectifier is a electronic circuit or a device which is used for converting AC voltage/current to DC voltage/current.

Requirements of rectifiers:- i) Rectifier is able to convert two directional Alternate Current (AC) to unidirectional pulsating Direct Current (DC).

ii) Rectifier removes, the negative part from Alternate Current (AC).

iii) By using Rectifier and step-down transformer we get desired DC voltage.

iv) Rectifier divided into two types:-  a) Half wave rectifier

                                                    b) Full wave rectifier

State concept of GPON

 

GPON or Gigabit passive optical network is a point to multipoint access mechanism.

The main characteristics of GPON is the use of passive splitters, which enable a single feeding fiber from the networks provider's central location to serve multiple users with their homes and small business. 

GPON uses the advanced Encryption standard (AES) for security purpose, which was designed to be efficient in both hardware and software and support a block length of 128 bits and key length 128, 192 and 256 bits.

GPON also support all types of Ethernet protocol.

Describe DWDM development of multiple wavelength with the help of a neat diagram. State its advantages also

Fig shows DWDM deployment on an OC-192 trunk ring for wavelength.

DWDM is a technology that puts together multiplexes data signals from different sources so, they can share a single optical fiber pair while maintaining complete partition of the data stream.

Individual signal is carried on a separate light wavelength. The dense part of DWDM refers to the fact that more than 80 separate wavelength, each about 0.8 of a nano-meter (nm) wide can short a single optical fiber.

DWDM allows enormous amount of data to traverse a single network link. Because they are

carried an clear wavelength, the streams also called channel do not interfere with each other.

Consequently data integrity if maintained of well as any security related positioning is also maintained.

Advantage:-

i) Improve scalability

ii) Provide extra resilience

iii) Maximum Capacity system available.

iv) Greater fiber capacity

v) Easier network expansion

vi) Can conserve switched bandwidth

vii) DWDM System Capable of longer span length

True or False in maths

1)  If A = {1,2,3} then {2,3} is proper subset of A.

True

False

Ans:- True

2) If A = {1, 2}, B = { 2, 3, 5 } and C = { 1, 2, 5 } then find A intersection B intersection C.

{2}

{1}

{3}

Ans:- {2}

What is the difference between potentiometer as an error detector and synchro as an error detector

 1) Potentiometer →  Two pots connected in uniform.

2) Synchro → Interconnection of a synchro transmitter and synchro control transformer.

3) Potentiometer → Potentiometer as an error detector associated with angular as well as linear position control system.

4) Synchro → Synchro as an error detector associated with only angular position control.

Enlist the effect of adding a zero and a pole in transfer function of system

 When a zero is added in the transfer function

1) Bandwidth increases, hence rise time decreases

2) Setting time increases

3) System more stable

When a pole is added in the transfer function

1) Bandwidth decreases hence rise time increases

2) Resonance peaks (Mr) increase

3) System become less stable

Draw the diagram of two fiber UPSR and explain how it is useful in stand by mode of continuous fiber optic communication

 

Block Diagram of Two fiber UPSR









The full form of UPSR is Two Fiber Unidirectional Path Switched Ring (UPSR).
Normally the working of traffic travels clockwise around the ring on primary path.

Connection from Node 1 to Node 3 links 1 & 2.
Traffic clockwise path is the protection path, if the link or Node fails, protection path (Link 5 to 8) is indicated by dashed lines.

To achieve protection, signals from a transmitting Node is a dual fed into both primary and protection fiber.

In case of failure of fiber optic communication, how does four fiber BLSR help. Explain with neat diagram

 

The full form of BLSR is Bidirectional Line Switched Ring.
Two primary fiber loops (1p to 8p) are used for normal bidirectional communication.
And other two secondary fiber loops are stand by links for protection purposes (1s to 8s).

Lets consider, the connection between Node 1 and Node 3 then traffic from Node 1 to Node 3 flow in clockwise direction links 1p & 2p.
In return path, traffic flow counter clockwise from Node 3 to Node 1 along links 7p & 8p.
If a transmitter or receiver circuit card fails, then the affected Node detects a loss of signal condition.
And switches both primary fiber connecting Nodes to secondary protection pair.

So in that condition four fiber bidirectional line switched ring is very useful and helpful.