RBSE Sec Voc Telecom flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Ohm's Law

Current through a conductor is directly proportional to applied voltage and inversely proportional to resistance, expressed as V = IR, where V is volts, I amperes and R ohms.

Zener Diode

A heavily doped diode operated in reverse breakdown to hold a nearly constant voltage across its terminals, used for voltage regulation and reference levels in power supplies.

LC Resonance

A series or parallel LC circuit resonates when inductive and capacitive reactances are equal, giving resonant frequency f0 = 1/(2π√(LC)) and minimum or maximum impedance depending on configuration.

AM Modulation Index

Ratio of modulating signal amplitude to carrier amplitude, m = Vm/Vc. Values above one cause overmodulation and distortion; total power equals Pc(1 + m²/2).

Carson's Rule

Approximate FM bandwidth equal to twice the sum of peak frequency deviation and highest modulating frequency, written as BW ≈ 2(Δf + fm) for wideband frequency modulation.

Sampling Theorem

A band-limited signal with highest frequency fm can be reconstructed exactly if sampled at fs ≥ 2fm; lower sampling rates cause aliasing, prevented by an anti-alias filter.

Erlang Traffic Formula

Traffic intensity in erlangs equals call arrival rate multiplied by mean holding time; one erlang means one circuit is continuously occupied for the whole measurement period.

PCM E1 Frame

Thirty-two time slots of eight bits transmitted 8000 times per second, giving 2.048 Mbit/s; slot zero carries framing and slot sixteen carries signalling.

SS7 Signalling

Common channel signalling system using a dedicated packet link and layered protocols MTP, SCCP, ISUP and TCAP, enabling fast call setup and database services in telephone networks.

Shannon Capacity

Maximum error-free data rate of a noisy channel, C = B log2(1 + S/N) bit/s, where B is bandwidth and S/N is the linear signal-to-noise power ratio.

Manchester Coding

A line code where each bit has a transition at mid-bit, high-to-low or low-to-high, providing self-clocking and zero DC average but requiring twice the bandwidth of NRZ.

Hamming Code

An error-correcting block code adding r parity bits to m data bits such that 2^r ≥ m + r + 1, allowing detection and correction of single-bit errors.

TCP Three-Way Handshake

Connection setup using SYN, then SYN-ACK from the server, then ACK from the client, synchronising sequence numbers before data transfer begins on a reliable transport connection.

Subnet Mask

A 32-bit pattern marking network and host portions of an IPv4 address; a /24 mask leaves eight host bits, giving 254 usable addresses after network and broadcast.

DHCP DORA

Four-step address assignment: Discover broadcast by client, Offer from server, Request from client accepting the offer, and Acknowledge confirming the lease and parameters.

Numerical Aperture

Light-gathering measure of a fibre, NA = √(n1² − n2²), where n1 and n2 are core and cladding refractive indices; its arcsine gives the acceptance angle.

Fibre Attenuation

Signal loss expressed as 10 log10(Pin/Pout) decibels; single-mode fibre reaches about 0.2 dB/km at 1550 nm, the lowest-loss telecom window.

OTDR

Optical time domain reflectometer that sends pulses and measures backscatter and reflections, reporting splice loss, connector loss, fibre length and fault location along a link.

Frequency Reuse Factor

Cluster size N = i² + ij + j² in a cellular plan; the same frequencies repeat in cells separated by reuse distance D = R√(3N) to limit co-channel interference.

OFDMA

Orthogonal frequency division multiple access, dividing a wideband carrier into many narrow orthogonal subcarriers and allocating subsets to users; used in 4G and 5G downlinks.

5G URLLC

Ultra-reliable low-latency communication service class of IMT-2020 targeting about one millisecond latency and very high reliability for industrial control and remote operation.

EIRP

Effective isotropic radiated power, the product of transmitter power and antenna gain reduced by feed losses, usually stated in dBm or dBW for link budget calculations.

Free-Space Path Loss

Spreading loss between isotropic antennas, FSPL(dB) = 32.44 + 20log10(d in km) + 20log10(f in MHz), increasing with both distance and frequency.

VSWR

Voltage standing wave ratio, (1 + |Γ|)/(1 − |Γ|), where Γ is the reflection coefficient; 1:1 means perfect match and 1.5:1 reflects about four percent power.

Rectangular Waveguide Cutoff

Lowest propagating mode TE10 has cutoff frequency fc = c/(2a), where a is the broad wall dimension; signals below cutoff are attenuated evanescently.

TRAI

Telecom Regulatory Authority of India, the statutory regulator that issues tariff orders, quality-of-service norms and recommendations on telecom and broadcasting matters.

Unified Licence

Indian telecom licence framework permitting an operator to offer access, national long distance, international long distance and internet services under one authorisation, subject to fees.

Laser Eye Safety

Invisible 1310 and 1550 nm fibre laser light can cause retinal damage; never view a fibre end or connector without confirming the source is off and using proper procedures.

NSQF Level

National Skills Qualification Framework ranks competencies from level one to ten by complexity, autonomy and knowledge, linking vocational courses to recognised job roles.

Demonstration Method

Teacher performs the operation step by step while explaining, followed by learner imitation under supervision, commonly used for splicing, crimping and instrument use in telecom labs.

Rubric Assessment

A scoring guide listing criteria and performance levels, used to judge practical work consistently and give learners specific feedback on procedure, safety and accuracy.

Guru Shikhar

Highest peak of the Aravalli range and of Rajasthan, located near Mount Abu in Sirohi district, standing about 1722 metres above sea level.