BSNL JTO key terms

The loss of signal strength as it travels along a cable, fibre, or radio path, usually measured in decibels per unit length or per kilometre.

A logarithmic unit that compares two power or voltage levels, widely used to express gain, loss, and signal-to-noise margins in telecom systems.

A thin glass or plastic strand that carries information as pulses of light, offering very high bandwidth and immunity to electromagnetic interference over long distances.

A technique that sends several independent signals simultaneously over one fibre by assigning each a different light wavelength, multiplying the capacity of that fibre.

Combining multiple separate information streams into one shared transmission medium so that several users or channels use the same link efficiently.

A digital cellular access scheme in which each radio channel is split into repeating time slots, and each user transmits only during an assigned slot.

The process by which a mobile network transfers an active call or data session from one cell or base station to another as the subscriber moves.

The radio equipment and antennas at a cell site that transmit to and receive from mobile handsets and connect them to the rest of the network.

Dividing a service area into many small radio cells, each with its own low-power base station, so frequencies can be reused with acceptable interference.

Assigning the same radio channels to cells that are far enough apart that their signals do not interfere significantly, thereby raising overall system capacity.

Interference caused by two or more transmitters using the same frequency at the same time, degrading reception in the affected receiver.

The ratio of wanted signal power to unwanted noise power at a point in a system, indicating how clearly the information can be recovered.

A seven-layer conceptual framework describing how network functions are organised, from physical transmission up to user applications, used to reason about protocols.

The practical set of internet protocols in which IP delivers packets across networks and TCP provides reliable, ordered, connection-oriented transport between hosts.

The process of selecting a path through one or more networks for a packet, based on addressing information and a routing table maintained by routers.

A 32-bit pattern used with an IPv4 address to separate the network portion from the host portion, defining which addresses are local to a subnet.

An addressing and routing method that uses variable-length prefixes, written like /24, instead of fixed address classes, conserving IPv4 space and shrinking routing tables.

A connection-oriented packet-switching technology that carries all traffic in small fixed-length 53-byte cells, supporting voice, video, and data with quality guarantees.

A set of mechanisms that prioritise or reserve network resources so that delay-sensitive traffic such as voice receives adequate bandwidth, low latency, and low jitter.

Variation in the arrival time of successive packets belonging to the same stream, which can cause glitches in real-time voice or video unless buffered or controlled.

The time delay between sending a signal or packet and its arrival at the destination, made up of propagation, transmission, processing, and queuing delays.

For a noiseless channel of bandwidth B, the maximum symbol rate without intersymbol interference is 2B symbols per second, setting a theoretical limit on signalling speed.

States that the maximum error-free data rate of a noisy channel equals B log2(1 + S/N), where B is bandwidth and S/N is the signal-to-noise power ratio.

The step in analogue-to-digital conversion that rounds each sampled value to the nearest of a finite set of levels, introducing a small quantisation error or noise.

An analogue signal containing no frequencies above f-max can be reconstructed exactly if sampled at a rate greater than twice f-max, the Nyquist rate.

A digital encoding method that samples an analogue signal at regular intervals, quantises the samples, and represents each as a binary code for transmission.

An analogue modulation scheme in which the instantaneous frequency of a carrier is varied in proportion to the message signal, giving good immunity to amplitude noise.

A feedback circuit that locks an oscillator's phase to a reference signal, used for frequency synthesis, clock recovery, and demodulation in communication receivers.

A high-gain differential voltage amplifier used with external feedback networks to build adders, filters, buffers, and precise gain stages in analogue circuits.

Returning a fraction of an amplifier's output to its input in opposing phase, which stabilises gain, widens bandwidth, and reduces distortion at the cost of lower gain.

A pair of graphs showing a system's magnitude and phase response against logarithmic frequency, used to judge stability margins and bandwidth of feedback circuits.

A mathematical system of binary variables and logic operations such as AND, OR, and NOT, used to simplify and design digital logic circuits.

A grid arrangement of truth-table entries used to simplify Boolean expressions by visually grouping adjacent cells that differ in only one variable.

A bistable digital storage element that holds one bit and changes state on a clock edge or input condition, forming the basis of registers and counters.

A programmable integrated circuit that fetches, decodes, and executes instructions, containing an arithmetic logic unit, registers, and control circuitry on one chip.

A small, fast memory placed close to the processor that holds recently used data and instructions to reduce average access time to main memory.

A technique that gives programs an enlarged, contiguous address space by mapping pages to physical memory or disk, with hardware assisting translation.

A situation where two or more processes each hold a resource and wait indefinitely for another held by the others, so none can proceed.

Organising relational database tables to remove redundancy and update anomalies by splitting them according to functional dependencies into higher normal forms.

The standard language for defining, querying, and modifying data in relational databases, including statements such as SELECT, INSERT, UPDATE, and DELETE.

Changing a value's representation between bases such as binary, octal, decimal, and hexadecimal while preserving its magnitude, a routine aptitude and digital-electronics skill.

Comparing quantities by division and equating two such comparisons, used to solve problems on mixtures, partnership shares, and scaling in the aptitude section.

A fraction expressed out of one hundred, used to describe increase, decrease, discount, and interest, and frequently converted to and from fractions in numerical questions.

A class of aptitude problems where rates of completing a job are added or compared to find combined completion time or individual efficiency.

A reasoning question presenting two or more premises and asking which conclusion necessarily follows from them, solved with set diagrams or rules of validity.

A reasoning topic in which family relationships described in a passage must be decoded to identify how two named persons are related.

A reasoning task requiring identification of the pattern governing a sequence of numbers, letters, or figures so that the next or missing element can be found.