Data Communication
Q. Criteria for cable selection for data transmission
A. Selection depends on Bandwidth requirements, transmission distance (attenuation), electromagnetic interference (EMI) resistance, and cost.
Q. 2.4GHz vs 5GHz WiFi performance
A. 5 GHz offers higher speeds and less congestion but has a shorter range. 2.4 GHz has better wall penetration but is often congested by other household devices (Bluetooth, microwaves).
Q. What is the baud rate of a channel transferring 20 symbols in 5 seconds?
A. Baud rate = Total Symbols / Total Time = 20 / 5 = 4 Baud.
Q. Why are wireless channels more prone to bit errors than wired?
A. Due to multi-path fading, atmospheric interference, shadowing, and the open nature of the medium which introduces more noise.
Frequency Bands
Q. What is the SHF frequency range?
A. Super High Frequency (SHF) ranges from 3 GHz to 30 GHz.
Q. What is the UWB frequency range?
A. Ultra-Wideband (UWB) typically operates in the 3.1 GHz to 10.6 GHz range.
5G & Antennas
Q. How does 5G achieve higher reliability than 4G?
A. Through URLLC (Ultra-Reliable Low Latency Communications) features, advanced channel coding (LDPC/Polar codes), and massive MIMO.
Q. The best antenna spacing for a Broadside Array (BSA) is:
A. Generally $\lambda/2$ (half-wavelength) to avoid grating lobes while maintaining high directivity.
Networking & IoT
Q. The data plane in the network model is responsible for:
A. Forwarding user data packets from an input interface to an output interface based on the control plane's logic.
Q. What is Machine-to-Machine (M2M) communication in IoT?
A. It refers to automated data exchange between devices without human intervention (e.g., a smart meter sending usage data to a utility server).
Signal Processing
Q. What is Aliasing?
A. Aliasing is a distortion that occurs when a signal is sampled at a rate less than the Nyquist rate, causing high-frequency components to "fold" into lower frequencies.
Q. What is a Raised Cosine Filter?
A. It is a pulse-shaping filter used in digital modulation to minimize Inter-Symbol Interference (ISI) by providing a smooth transition in the frequency domain.