InterviewSolution

Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

51.	Waveform coders and Vocoders are the types of ____________(a) Speech coders(b) Modulation technique(c) Frequency translation methods(d) Channel allocation for transmissionThis question was addressed to me during an online interview.Enquiry is from Frequency Domain Coding of Speech in chapter Speech Coding of Wireless/Mobile
Answer» RIGHT answer is (a) Speech CODERS For explanation I would say: Speech coders can be classified into waveform coders and Vocoders. Waveform coders convert the ANALOG signal into digital signal. Vocoders EXPLOIT the SPECIAL properties of speech signal to reduce the bit rate.

52.	In frequency domain coding of speech, the number of bits used to encode each frequency component is constant.(a) True(b) FalseThe question was asked by my college professor while I was bunking the class.Question is from Frequency Domain Coding of Speech topic in division Speech Coding of Wireless/Mobile
Answer» The correct answer is (b) False The best I can explain: Frequency domain coders have an advantage that number of bits USED to encode each frequency component can be dynamically varied. They can ALSO be shared among DIFFERENT bands.

53.	________ exaggerates the bit errors originally received at the base station.(a) Non linear transformation(b) Tandem signalling(c) Large cell size(d) Complex vocodersI got this question in an internship interview.My question comes from Speech Codecs in section Speech Coding of Wireless/Mobile
Answer» Right choice is (B) Tandem signalling Easy explanation: Tandem signalling tends to EXAGGERATE the bit errors ORIGINALLY received at the BASE station. Tandem signalling is difficult to protect against but is an important evaluation criterion in the evaluation of SPEECH coders.

54.	Frequency domain coders divides the speech signal into __________(a) A set of frequency components(b) A set of different amplitudes(c) A set of time delays(d) A set of phase componentsThe question was posed to me by my college professor while I was bunking the class.This interesting question is from Frequency Domain Coding of Speech in portion Speech Coding of Wireless/Mobile
Answer» The correct option is (a) A set of frequency COMPONENTS To EXPLAIN I WOULD say: In the CLASS of frequency domain coders, the speech signal is divided into a set of frequency components. Each frequency component is quantized and encoded SEPARATELY.

55.	Vocoders analyse the speech signals at ______(a) Transmitter(b) Receiver(c) Channel(d) IF FilterThis question was posed to me during an online exam.The above asked question is from Vocoders topic in division Speech Coding of Wireless/Mobile
Answer» RIGHT choice is (a) Transmitter The explanation: VOCODERS are a CLASS of speech CODING systems. They analyse the speech signal at the transmitter. And then transmit the parameters derived from the analysis.

56.	Distortion produced by quantization is directly proportion to ________ and inversely proportional to ______(a) Number of levels, step size(b) Amplitude of the signal, step size(c) Square of step size, number of levels(d) Amplitude of the signal, number of levelsI had been asked this question by my college professor while I was bunking the class.I would like to ask this question from Quantization Techniques topic in section Speech Coding of Wireless/Mobile
Answer» The CORRECT CHOICE is (c) Square of step SIZE, number of levels Easiest EXPLANATION: The distortion introduced by any quantization operation is DIRECTLY proportional to the square of the step size. It is inversely proportional to the number of levels for a given amplitude range.

57.	Low frequency signals contribute very little to the total speech signals.(a) True(b) FalseThis question was posed to me in an interview for internship.This question is from Characteristics of Speech Signals in division Speech Coding of Wireless/Mobile
Answer» The correct answer is (b) False Best explanation: LON term AVERAGED PSD’s of speech show that high frequency signals contribute very little to the total speech ENERGY. However, high frequency components are insignificant in energy, they are very important carriers of speech information.

58.	Formant vocoders use large number of control signals.(a) True(b) FalseI have been asked this question by my college professor while I was bunking the class.Enquiry is from Vocoders in portion Speech Coding of Wireless/Mobile
Answer» Right CHOICE is (b) False To ELABORATE: Formant vocoders use fewer control signals. Therefore, formant vocoders can operate at lower bit rates than the CHANNEL VOCODER. Instead of transmitting the power spectrum envelope, formant vocoders attempt to transmit the position of peaks of SPECTRAL envelope.

59.	Which of the following LPC uses two sources at the receiver?(a) Multiple excited LPC(b) Residual excited LPC(c) LPC Vocoders(d) Code excited LPCI got this question by my school principal while I was bunking the class.This key question is from Linear Predictive Coders in portion Speech Coding of Wireless/Mobile
Answer» Correct ANSWER is (c) LPC Vocoders The best explanation: LPC vocoder uses TWO sources at the RECEIVER, one of white noise and the other with a SERIES of pulses at the current pitch rate. The SELECTION of either of these excitation methods is based on voiced/unvoiced decision made at the transmitter.

60.	________ is often called the formant of the speech signal.(a) Pitch frequency(b) Voice pitch(c) Pole frequency(d) Central frequencyThis question was posed to me during an interview for a job.This interesting question is from Vocoders in section Speech Coding of Wireless/Mobile
Answer» Correct ANSWER is (c) Pole frequency The EXPLANATION is: The pole frequencies correspond to the resonant frequencies of the vocal TRACT. They are often CALLED the formants of the speech signal. For ADULT speakers, the formants are centered around 500 Hz, 1500 Hz, 2500 Hz and 3500 Hz.

61.	The characteristics of compressor in μ-law companding are _________(a) Continuous in nature(b) Logarithmic in nature(c) Linear in nature(d) Discrete in natureThis question was posed to me in an interview for job.My enquiry is from Quantization Techniques topic in portion Speech Coding of Wireless/Mobile
Answer» Correct answer is (a) Continuous in nature For explanation: In the μ law companding, the compressor characteristic is continuous. It APPROXIMATES the LINEAR dependence on X for low INPUT signals and a LOGARITHMIC one for high input signals.

62.	Vocoders __________ the voice at the receiver.(a) Analyse(b) Synthesize(c) Modulate(d) EvaluateThis question was posed to me in an interview.I would like to ask this question from Vocoders topic in section Speech Coding of Wireless/Mobile
Answer» The CORRECT option is (b) Synthesize Explanation: Vocoders synthesize the voice at the receiver. All VOCODER systems attempt to model the SPEECH generation process as a DYNAMIC system and try to quantify certain physical constraints of the system.

63.	The speech coding technique that is dependent on the prior knowledge of the signal is __________(a) Waveform coders(b) Vocoders(c) Sub band coding(d) Block transformI have been asked this question by my college director while I was bunking the class.My enquiry is from Frequency Domain Coding of Speech in division Speech Coding of Wireless/Mobile
Answer» The CORRECT OPTION is (B) Vocoders Explanation: Vocoders are dependent on the prior KNOWLEDGE of the signals. They capture the characteristic elements of audio signal and then uses this characteristic signal to affect other audio signals.

64.	Quantization is a ________ process.(a) Linear(b) Direct(c) Non-linear(d) IndirectThis question was addressed to me during an online exam.Query is from Frequency Domain Coding of Speech topic in section Speech Coding of Wireless/Mobile
Answer» CORRECT option is (c) Non-linear Explanation: Quantization is a non-linear process. It produces DISTORTION products that are typically broad in SPECTRUM.

65.	Waveform coders has _______ complexity and achieves _______ economy in transmission bit rate.(a) Maximum, moderate(b) Maximum, high(c) Minimal, moderate(d) Minimal, highI have been asked this question in a job interview.I would like to ask this question from Characteristics of Speech Signals in chapter Speech Coding of Wireless/Mobile
Answer» Correct choice is (C) Minimal, moderate For EXPLANATION I WOULD SAY: Waveform coders have minimal complexity. This class of coders achieves only moderate ECONOMY in transmission bit rate. They are designed to be source independent and hence code equally well a variety of signals.