FOURTH SEMESTER B.Sc. (L.R.P.) DEGREE EXAMINATION, APRIL 2017 (CUCBCSS—UG) Common Course A 14—BASICS OF AUDIO AND VIDEO MEDIA
calicut university bca avs question paper and answers 2017
1. The power of speech signals can be expressed in _____
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
5. recording is based on magnetization of magnetic materials in an external magnetic field.
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
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
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.
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
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.
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
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.
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.
1. Electrical Impedence
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.
ii. Uni Directional
iii. Bi Directional
18. Discuss the following characteristics of a microphone -sensitivity, S/N ratio and frequency 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
> 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
> 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.
20. Discuss digital coding using A/D parallel and flash methods.
21. Derive the relation between tape speed and band width explaining each.
22. Discuss H26 compression standards.
23. Discuss the electrodynamic loud speaker.
24. Distinguish parametric and graphic equalisers.
25. Distinguish MPEG 1, 2 and 3.
Answer any two questions. Each question carries 15 marks
26. Explain the construction and working of to moving coil microphone.
27. Discuss digital tape recording systems
28. Discuss recording of video signals on magnetic tape and its reproduction with block diagrams.
29. Discuss magnetic recording on a tape and explain recorded wavelength, gap width and tape speed.