Reference

Since the line frequency (number of lines per second) is 15625 Hz (625 lines × 50 Hz ÷ 2), the colour carrier frequency calculates as follows: 4.43361875 MHz = 283.75 × 15625 Hz + 25 Hz. ... Almost all other countries using system M use NTSC. The PAL colour system ... standard uses the same video system as PAL-B/G/H (625 lines, 50 Hz field ...

A similar 525-line system was adopted by countries using 60 Hz utility frequency (like the US). ... [13] This was initially known as the I.B.T.O. 625-line system. At a CCIR Geneva meeting in July 1950, Dr. Gerber (a Swiss engineer), proposed a modified 625-line system using a 7 MHz channel bandwidth ...

Analog TV systems global map, with System B in blue. CCIR System B (originally known as the "Gerber Standard" [1][2][3][4]) was the 625-line VHF analog broadcast television system which at its peak was adopted by more than one hundred countries, either with PAL or SECAM colour. [5] It is usually associated with CCIR System G for UHF broadcasts ...