why number of scanning lines per frame always odd in television?
Answer / jaldip jayswal
If you had an even number of lines then all lines must start
at the beginning of the frame. If you have an odd number of
lines then you will achieve the same resolution on the
screen but the half line (the odd line), split in half with
half at the start of the second frame and half at the end of
the second frame allows for an extra line period in order to
flyback vertically.
This "appears" to the human eye to be a better picture. If
you think about the lines, they are all sloping so if you
use full lines then for a full line scan the area at the top
right and bottom left have no data in for a wider area than
with half line second frame scan. The missing data area
remains the same but is now split into two parts,
immediately before the half line starts and at the end of
the first half line.
For interlaced scanning, an odd number of lines per frame
was required in order to make the vertical retrace distance
identical for the odd and even fields, which meant the
master oscillator frequency had to be divided down by an odd
number. At the time, the only practical method of frequency
division was the use of a chain of vacuum tube
multivibrators, the overall division ratio being the
mathematical product of the division ratios of the chain.
Since all the factors of an odd number also have to be odd
numbers, it follows that all the dividers in the chain also
had to divide by odd numbers, and these had to be relatively
small due to the problems of thermal drift with vacuum tube
devices. The closest practical sequence to 500 that meets
these criteria was 3 × 5 × 5 × 7 = 525.
| Is This Answer Correct ? | 14 Yes | 3 No |
How to programme PIC microcontroller.
Sparking occur when a load is switched off because the circuit has high a.) Inductance b.) Capacitance c.) Resistance d.) None
14 Answers Biwta, BSNL, CDS, DMRC, Infosys, SSC,
What's the difference betweem Pulse dopler radar and MTI RADAR....
Hai Frds, i want to join in testing tools course, pls sugest good institute. And pls tel about Mind Q institute & phone num of Nareswar Roa sir plss, ple mail me plssssss
HOW TO INTERFACE A "MOTOR ASSEMBLY UNIT" WITH 8085 MICROPROCESSOR? MEANS HOW CAN WE USE 8085 TO ASSEMBLE DIFFERENT PARTS OF A VEHICLE?????
WHAT IS MEAN BY GMT
i completed my b.tech recently with full credits... i have confused in calculating my backlogs...actually i failed in 6 subjects(1 in 2-1,4 in 3-2,1 in 4-1) but i cleared them in one attempt in their respective supplymentry.... then how many backlogs i had now... tell me cleraly.....
Explain the different modes of flyback converter
State the difference between ac and dc voltage.
Explain in detail the thevenin`s theorem
what is the working of silicon controlled resistor
what's the cut in voltage for a led?
Civil Engineering (5086)
Mechanical Engineering (4456)
Electrical Engineering (16639)
Electronics Communications (3918)
Chemical Engineering (1095)
Aeronautical Engineering (239)
Bio Engineering (96)
Metallurgy (361)
Industrial Engineering (259)
Instrumentation (3014)
Automobile Engineering (332)
Mechatronics Engineering (97)
Marine Engineering (124)
Power Plant Engineering (172)
Textile Engineering (575)
Production Engineering (25)
Satellite Systems Engineering (106)
Engineering AllOther (1379)