How do 64us per second scanning in india television system?

In the Indian television system (PAL, 625 lines, 25 frames/sec), the horizontal scanning time is 64 µs per line, not per second.

Let’s break it down clearly:

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1. Frame rate:
25 frames per second.

2. Total lines per frame:
625 lines (including blanking lines).

3. Active lines per frame:
About 585 visible lines; the rest are blanked for synchronization and retrace.

4. Time for 1 frame:
$\frac{1}{25}$ second = 40,000 µs.

5. Time for 1 line (including blanking):

$$\frac{40,000\mu \text{s}}{625\text{ lines}}=64\mu \text{s per line}\mathrm{.}$$

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What happens in 64 µs?

• ~52 µs → Active trace (beam moves left to right, drawing the picture).

• ~12 µs → Horizontal blanking & retrace (beam returns invisibly to the left).

This 64 µs per line repeats 625 times to complete 1 frame in 40,000 µs, and 25 such frames are scanned per second.

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So 64 µs is the time to scan one horizontal line, not per second. It ensures smooth and synchronized picture display in the Indian TV system.