is removed from PAL and NTSC-encoded signals with a comb filter (designed to segregate the two signals where the luma spectrum may overlap into the spectral space used by the chroma) by modern displays, some can still be left in certain parts of the picture. Such parts are usually sharp edges on the picture, sudden color or brightness changes along the picture or certain repeating patterns, such as a checker board on clothing. FM SECAM is a continuous spectrum, so unlike PAL and NTSC even a perfect digital comb filter could not entirely separate SECAM colour and luminance signals. SECAM varieties Broadcast systems L, B/G, D/K, H, K, M There are six varieties of SECAM, according to each of the broadcast system it was used with: SECAM-L: Used only in France, Luxembourg (only RTL9 on channel 21 from Dudelange) and Télé Monte-Carlo transmitters in the south of France. SECAM-B/G: Used in parts of the Middle East, former East Germany, Greece and Cyprus SECAM-D/K: Used in the Commonwealth of Independent States and parts of Eastern Europe (this is simply SECAM used with the D and K monochrome TV transmission standards) although most Eastern European countries have now migrated to other systems. SECAM-H: Around 1983–1984 a new color identification standard ("Line SECAM or SECAM-H") was introduced in order to make more space available inside the signal for adding teletext information (originally according to the Antiope standard). Identification bursts were made per-line (like in PAL) rather than per-picture. Very old SECAM TV sets might not be able to display colour for today's broadcasts, although sets manufactured after the mid-1970s should be able to receive either variant. SECAM-K: The standard used in France's overseas possessions (as well as African countries that were once ruled by France) was slightly different from the SECAM used in Metropolitan France. The SECAM standard used in Metropolitan France used the SECAM-L and a variant of the channel information for VHF channels 2–10. French overseas possessions and many French-speaking African countries use the SECAM-K1 standard and a mutually incompatible variant of the channel information for VHF channels 4-9 (not channels 2–10). SECAM-M: Between 1970 and 1991, SECAM-M was used in Cambodia and Vietnam (Hanoi and cities North). MESECAM (home recording) MESECAM is a method of recording SECAM color signals onto VHS or Betamax video tape. It should not be mistaken for a broadcast standard. "Native" SECAM recording (marketing term: "SECAM-West")