COURSE: AUDIO VIDEO ENGINNERING COURSE CODE: 17537 CHAPTER : 4. TV Transmitter and Receiver Marks: 20 Marks. Contents: Audio and Video signal transmission using AM and FM modulation. Positive and Negative modulation Introduction to TV camera tube (Vidicon, Plumbicon, Solid State camera based on CCD.) Color Picture tube (PIL, Delta gun picture tube, Trinitron) Block diagram of Colour TV transmitter. Block Diagram of color TV receiver (PAL D type) 20 September 201820 September 2018

Audio and Video signal transmission using AM and FM modulation. AM is preferred for picture because the following reasons, The distortion which arises due to interference between multiple signals is more objectionable in FM than AM because the frequency of the FM signal continuously changes. Hence, hardly any steady picture is produced. Alternatively if AM were used, the multiple signal paths can at most produce a ghost image which is steady. In addition to this, circuit complexity and bandwidth requirements are much less in AM than FM. TV Transmitter and Receiver 20 September 201820 September 2018

FM is preferred for sound because the following reasons, The bandwidth assigned to the FM sound signal is about 200 kHz of which not more than 100 kHz is occupied by sidebands of significant amplitude. The latter figure is only 1.4 per cent of the total channel bandwidth of 7 MHz. Thus, without encroaching much, in a relative sense, on the available band space for television transmission all the advantages of FM can be availed. TV Transmitter and Receiver 20 September 201820 September 2018

SUBJECT: AUDIO VIDEO ENGINNERING SUBJECT CODE: 17537 CHAPTER : 4. TV Transmitter and Receiver Marks: 20 Marks. Contents: Audio and Video signal transmission using AM and FM modulation. Positive and Negative modulation Introduction to TV camera tube (Vidicon, Plumbicon, Solid State camera based on CCD.) Color Picture tube (PIL, Delta gun picture tube, Trinitron) Block diagram of Colour TV transmitter. Block Diagram of color TV receiver (PAL D type) 20 September 201820 September 2018

Positive and Negative modulation Positive Modulation Negative Modulation 1. When increase in brightness of that picture results in an increase of the amplitude of modulated envelope.it is called positive modulation. When increase in brightness reduces amplitude of the modulated envelope, it is called negative modulation. 2. White level of video signal corresponds to 100% total magnitude. White level of video signal correspondence to 12.5% of the total amplitude. 3. Waveforms (next slide) 4. Noise pulses do not effect synchronization but cause white spot in the picture Noise pulses are seen as less annoying black spot. 5. More power is required with less efficiency If peak power available from transmitter is considered them less power is required for more efficiency. 6. Black level of video signal correspondence to 25% of total magnitude. Blanking level starts at 75% TV Transmitter and Receiver 20 September 201820 September 2018

TV Transmitter and Receiver 20 September 201820 September 2018

Merits & Demerits of Negative modulation Lesser noise interference on picture signal. Possible to obtain larger peak power output. Less picture signal distortion. Easy to develop true AGC voltage. More efficient operation. More power available from the transmitter Saving in transmission power Demerits: The synchronization of the receiver is affected by spurious random pulses produced due to the effect of noise. The loss of horizontal and vertical synchronization may cause diagonal or vertical rolling of picture. TV Transmitter and Receiver 20 September 201820 September 2018

SUBJECT: AUDIO VIDEO ENGINNERING SUBJECT CODE: 17537 CHAPTER : 4. TV Transmitter and Receiver Marks: 20 Marks. Contents: Audio and Video signal transmission using AM and FM modulation. Positive and Negative modulation Introduction to TV camera tube (Vidicon, Plumbicon, Solid State camera based on CCD.) Color Picture tube (PIL, Delta gun picture tube, Trinitron) Block diagram of Colour TV transmitter. Block Diagram of color TV receiver (PAL D type) 20 September 201820 September 2018

photoemission & photoconductivity. Photo electric effect: The two photoelectric effects used for converting variations of light intensity into electrical variations are photoemission & photoconductivity. TV Transmitter and Receiver 20 September 201820 September 2018

TV Transmitter and Receiver 20 September 201820 September 2018

Solid State camera based on CCD. Image orthicon TV camera tube Vidicon Plumbicon Solid State camera based on CCD. Image orthicon TV Transmitter and Receiver 20 September 201820 September 2018

Based on PHOTOCONDUCTIVITY Vidicon : Based on PHOTOCONDUCTIVITY TV Transmitter and Receiver 20 September 201820 September 2018

TV Transmitter and Receiver 20 September 201820 September 2018

Based on PHOTOCONDUCTIVITY Plumbicon: Based on PHOTOCONDUCTIVITY TV Transmitter and Receiver 20 September 201820 September 2018

TV Transmitter and Receiver 20 September 201820 September 2018

It is similar to vidicon tube except small change in target plate lower image lag. It has fast response and produce high quality pictures at low light level. It has small size and light weight and has low power operating characteristics . It is similar to vidicon tube except small change in target plate TV Transmitter and Receiver 20 September 201820 September 2018

Solid State camera based on CCD. TV Transmitter and Receiver 20 September 201820 September 2018

SUBJECT: AUDIO VIDEO ENGINNERING SUBJECT CODE: 17537 CHAPTER : 4. TV Transmitter and Receiver Marks: 20 Marks. Contents: Audio and Video signal transmission using AM and FM modulation. Positive and Negative modulation Introduction to TV camera tube (Vidicon, Plumbicon, Solid State camera based on CCD.) Color Picture tube (PIL, Delta gun picture tube, Trinitron) Block diagram of Colour TV transmitter. Block Diagram of color TV receiver (PAL D type) 20 September 201820 September 2018

PIL Delta gun Trinitron Colour Picture tubes TV Transmitter and Receiver 20 September 201820 September 2018

Delta gun: TV Transmitter and Receiver 20 September 201820 September 2018

DRAWBACKS OF DELTA GUN PICTURE TUBE: Convergence is difficult and involves considerable circuit complexity and service adjustments. In most delta-gun tubes, four static convergence magnets and a dynamic convergence assembly are employed. The focus cannot be sharp over the entire screen because the focus and convergence planes cannot remain coincident for the three beams which emanate from guns positioned at 120° with respect to each other around the tube axis. The electron transparency of the mask is very low since it intercepts over 80 percent of the beam currents. TV Transmitter and Receiver 20 September 201820 September 2018

PIL (Precision-in-line): TV Transmitter and Receiver 20 September 201820 September 2018

ADVANTAGES OF PIL: Due to vertical slots, electron transparency is about 50% which is much more than 20%. Hence its efficiency is better. Vertical convergence is not needed & hence convergence adjustment is less than required in delta gun. Focus is sharp all though the screen as the guns are in the same plane. TV Transmitter and Receiver 20 September 201820 September 2018

DRAWBACK Due to nonuniformity of the deflection field all the beams are not deflected by the same amount. As shown in Fig. the central beam (green) deflects by a smaller amount as compared to the other two beams. For a different nonuniformity of the deflection field, the effect could be just opposite producing too large a displacement of the central beam. Such a distortion is known as coma and results in misconvergence of the beams. TV Transmitter and Receiver 20 September 201820 September 2018

Trinitron: TV Transmitter and Receiver 20 September 201820 September 2018

ADVANTAGES OF TRINITRON: Improved Vertical resolution Greater transparency for the electron beam, being about 80% against 20% for delta gun & 50% for PIL. Consequently efficiency is high. Controls are only 6 against 12 each in delta gun & PIL. Sharper focus & brighter picture. No problem of convergence adjustment. TV Transmitter and Receiver 20 September 201820 September 2018

TV Transmitter and Receiver 20 September 201820 September 2018

SUBJECT: AUDIO VIDEO ENGINNERING SUBJECT CODE: 17537 CHAPTER : 4. TV Transmitter and Receiver Marks: 20 Marks. Contents: Audio and Video signal transmission using AM and FM modulation. Positive and Negative modulation Introduction to TV camera tube (Vidicon, Plumbicon, Solid State camera based on CCD.) Color Picture tube (PIL, Delta gun picture tube, Trinitron) Block diagram of Colour TV transmitter. Block Diagram of color TV receiver (PAL D type) 20 September 201820 September 2018

Block diagram of Colour TV transmitter. Colour Camera Matrix, Weighting Ckt & LPF Adder PAL Colour Encoder Sub Carrier Generator Gate Divider Sync. Pulses Video Carrier AMVSB mod. Diplexer FM Mod & Amp. Audio carrier Y Signal V Signal U Signal Colour Signal Sync. Pulse CCVS Audio Signal R G B Antenna TV Transmitter and Receiver 20 September 201820 September 2018

SUBJECT: AUDIO VIDEO ENGINNERING SUBJECT CODE: 17537 CHAPTER : 4. TV Transmitter and Receiver Marks: 20 Marks. Contents: Audio and Video signal transmission using AM and FM modulation. Positive and Negative modulation Introduction to TV camera tube (Vidicon, Plumbicon, Solid State camera based on CCD.) Color Picture tube (PIL, Delta gun picture tube, Trinitron) Block diagram of Colour TV transmitter. Block Diagram of color TV receiver (PAL D type) 20 September 201820 September 2018

Block Diagram of color TV receiver (PAL D type) TV Transmitter and Receiver 20 September 201820 September 2018

Monochrome Colour Television R.R.GULATI page no: 551 TV Transmitter and Receiver 20 September 201820 September 2018

SUBJECT: AUDIO VIDEO ENGINNERING SUBJECT CODE: 17537 CHAPTER : 4. TV Transmitter and Receiver Marks: 20 Marks. Contents: Audio and Video signal transmission using AM and FM modulation. Positive and Negative modulation Introduction to TV camera tube (Vidicon, Plumbicon, Solid State camera based on CCD.) Color Picture tube (PIL, Delta gun picture tube, Trinitron) Block diagram of Colour TV transmitter. Block Diagram of color TV receiver (PAL D type) 20 September 201820 September 2018