1. Communication Systems (EC-326)
TELEVISION - 2
Communication Systems (EC-326)

2. EC 326 COMMUNICATION SYSTEMS UNIT - III
T Srinivasa Rao
Dept. of ECE
Bapatla Engineering College

3. Communication Systems (EC-326)
Part 1
Vision characteristics and scanning systems, Composite video signal.
Part 2
Camera tubes: Principle of operation, Image Orthicon, Vidicon, Plumbicon.
Part 3
Block diagram of broad cast TV transmitter
Block diagram of broadcast TV receiver.
Communication Systems (EC-326)

4. Simplified cross-sectional view of a Vidicon TV camera tube
Communication Systems (EC-326)

5. Elements of a picture tube
Communication Systems (EC-326)

6. Communication Systems (EC-326)
Signal transmission paths illustrating compatibility between colour and monochrome TV systems. R, G and B represent three camera tubes which develop video signals corresponding to the red, green and blue contents of the scene being televised
Communication Systems (EC-326)

7. A Rectangular Picture Tube
Communication Systems (EC-326)

8. Communication Systems (EC-326)
Monochrome Picture Tube
One Electron Gun
Continuous phosphor coating
Colour Picture Tube
Three electron beams
Three phosphors.
Communication Systems (EC-326)

9. Communication Systems (EC-326)

10. Communication Systems (EC-326)
Electron Gun
Control Grid
Accelerating Grid
Focusing Grid
Communication Systems (EC-326)

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20. Vidicon camera tube cross-section
Communication Systems (EC-326)

21. Circuit for output signal from a Vidicon camera tube
Communication Systems (EC-326)

22. Leaky Capacitor Concept
Communication Systems (EC-326)

23. Communication Systems (EC-326)
THE PLUMBICON
Target Details Output Signal Current Characteristics
Communication Systems (EC-326)

24. Communication Systems (EC-326)

25. Switcher for selecting any camera output to one monitor.
A sync generator driving
several camera units
Communication Systems (EC-326)

26. Block diagram of a drive and sync pulse generator
Communication Systems (EC-326)

27. Block Diagram of a Television Transmitter
Communication Systems (EC-326)

28. Rear view of a black and white receiver with the back removed
Communication Systems (EC-326)

29. Block diagram of a monochrome television receiver
Communication Systems (EC-326)

30. Communication Systems (EC-326)

31. CHOICE OF INTERMEDIATE FREQUENCY IN TV
(i) Image Rejection Ratio
(ii) Pick-up Due to Local Oscillator Radiation from TV Receivers
(iii) Ease of Separation of Modulating Signal from IF Carrier at the Demodulator
(iv) Image Frequencies Should Not Lie in the FM Band
(v) Interference or Direct Pick-Up from Bands Assigned for other Services
(vi) Gain
Communication Systems (EC-326)

32. Communication Systems (EC-326)
V S B CORRECTION
Communication Systems (EC-326)

33. Communication Systems (EC-326)
VIDEO DETECTOIN
Communication Systems (EC-326)

34. Detector and filter circuit of a radio receiver
Communication Systems (EC-326)

35. Communication Systems (EC-326)
REQUIREMENTS
(a) The detector load must provide a suitable impedance as seen through the diode, at input of the detector to tune and damp secondary of the last IF coupling circuit correctly. (b) The detector load must remove from the output, the IF content in the signal as much as possible. For this purpose the load usually includes one or two low-pass filter sections. (c) The detector load should have a trap circuit (a series rejector circuit) for separating the intercarrier sound signal. (d) The detector load must also include a provision to boost the higher video frequencies to compensate for the loss due to input capacitance of the video amplifier.
Communication Systems (EC-326)

36. FUNCTIONS OF THE COMPOSITE VIDEO SIGNAL
Communication Systems (EC-326)

37. SOUND SIGNAL SEPARATION
Communication Systems (EC-326)

38. Block diagram of AGC system
Communication Systems (EC-326)

39. High Voltage (EHT) Supply
Communication Systems (EC-326)

40. Communication Systems (EC-326)
Deflection Circuits
Communication Systems (EC-326)

41. Communication Systems (EC-326)

42. Operating Controls of a T V Receiver
Channel Selector
Fine Tuning
Volume
Tone
Contrast
Brightness
Vertical Hold
Horizontal Hold.
Communication Systems (EC-326)

43. Next… Colour Television…
Communication Systems (EC-326)