calicut university bca avs question paper and answers 2017

Part I

1. The power of speech signals can be expressed in _____
Ans:Decibal

2. Reverberation is caused by _______ of sound waves
Ans:Reflection of sound wave

3. For quality microphones nonlinear distortion should be less than
Ans: It should be less than 5%

4. A transducer that converts sound wave,to electrical signals is called
Ans:Microphone

5. recording is based on magnetization of magnetic materials in an external magnetic field.
Ans:

6. The expansion of MPEG is_____
Ans: Moving Picture Expert Group

7. Ultrasonic’s refer to sound waves having frequency above ______ Hz
Ans:Above 20000Hz (20KHz)

8. Name the nerve that carry signals from ear to brain
Ans:Choeclear Nerve

9. The base coating material in a magnetic tape is
Ans:Either plastic or metal. Plastic type is used more than metal

10. A camera converts brightness and color into signals
Ans:Electric Signal

Part II

11. What are the factors on which reverberation time depends?
Ans:Reverberation time depends on size and shape of the space along with the amount,Quality & position of absorbing surface within the space

12. Explain Sabine, formula for reverberation time.
Ans:

Sabines Reverberation Equation
It is the Relationship between the T60(Reverbe Time) of a room,Its volume & Its total absorbtion. This is given by this rquation

T60 = 24ln10

Where,
C20 – Speed of sound in room with 20C
V – Volume
S – Surface Area
a – Average absorbtion coefficient of room
Sa – Total absorbtion in sabins

13. Explain any two noise reduction techniques.
Ans:
i. Compounds based on noise reduction system
ii. Dynamic noise limiter & Dynamic noise reduction
iii. Softwear programmes
iv. To reduce noise in hall use sound absorbtion materiels

14. Explain about MP3
Ans: MP3
i. Formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III
ii. It is standard technology and format for compressing a sound sequence into a very small file
iii. It is identified with the filename of suffix .mp3

15. Explain the principle of analog video recording.
Ans:

Recording on Tape:
It is done in the form of tiny magnets. Reproduction is done usingthe principle of electro magnetic induction

Recording on disk:
It is done in the form of tiny pits.Reproduction is done by sencing the capacitance between stylus & pits.

16. List the characteristic that determine quality of a microphone.
Ans:
1. Electrical Impedence
2. Directivity
3. Frequencey Response
4. Signal to Noise Ratio

17. Define directivity of a microphone.
Ans:It is the pattern of sensing the sound relative to direction or angle which the sound arrives.
Types:
i. Omni-Directional
ii. Uni Directional
iii. Bi Directional

Part III

18. Discuss the following characteristics of a microphone -sensitivity, S/N ratio and frequency response.
Ans:Frequence Response
> The output level or sensitivity of the microphone over its operating range from lowest to highest
> A microphone whose output is equal at all frequency will have a flat frequency response
> A mikcrophone whose response has peaks and dips in certain frequencies shows shaped response
Microphone Sensitivity
> It is a measurment of microphone efficieny as a tranduser
> A microphone sensitivity rating is determined by its output voltage relative to the sound pressure level it subject to
Signal-to-Noise Ratio
> It is defined the ratio of signal power to the noise
> Expresed in Decibal(dB)
> A ratio higher than 1:1 indicates more signal than the ratio
> Which means higher the ratio, Micropone will give a good output

19. Discuss the principle, construction and working of a crystal microphone.
Ans:

20. Discuss digital coding using A/D parallel and flash methods.
Ans:

21. Derive the relation between tape speed and band width explaining each.
Ans:

22. Discuss H26 compression standards.
Ans:

23. Discuss the electrodynamic loud speaker.
Ans:

24. Distinguish parametric and graphic equalisers.
Ans:

25. Distinguish MPEG 1, 2 and 3.
Ans:

Part IV

Answer any two questions. Each question carries 15 marks

26. Explain the construction and working of to moving coil microphone.
Ans:

27. Discuss digital tape recording systems
Ans:

28. Discuss recording of video signals on magnetic tape and its reproduction with block diagrams.
Ans:

29. Discuss magnetic recording on a tape and explain recorded wavelength, gap width and tape speed.
Ans: