When the TV signal is transmitted by wireless broadcasting or wired transmission, the residual sideband amplitude modulation is used for the image signal, and the frequency modulation is used for the audio signal. The frequency band occupied by each TV program is 8MHz (Figure 07-03-9, taking China's TV standard as a parameter). Figure 07-03-9 Spectrum structure and channels of broadcast and television signals (Taking Chinese TV standard as parameter) The open-circuit TV signal stipulated in China is divided into 68 channels. Currently, only 1 to 48 channels are used by radio and television, and the fifth channel has been allocated to FM radio (Table 07-03-4). Table 07-03-4 Division of TV channels in China Frequency band Channel Image carrier Sound carrier frequency frequency band Center frequency VHF I 1 49.75 56.25 48.5 ~ 56.5 52.5 2 57.75 64.25 56.5 ~ 64.5 52.5 3 65.75 72.25 64.5 ~ 72.5 52.5 4 77.25 83.75 76 ~ 84 80 5 85.25 91.75 84 ~ 92 88 FM 87 ~ 108 VHF â…¢ 6 168.25 174.75 167 ~ 175 171 7 176.25 182.75 175 ~ 183 179 8 184.25 190.75 183 ~ 191 187 9 192.25 198.75 191 ~ 199 195 10 200.25 206.75 199 ~ 207 203 11 208.25 214.75 207 ~ 215 211 12 216.25 222.75 215 ~ 223 219 UHF â…£ 13 471.25 477.75 470 ~ 478 474 14 479.25 485.75 478 ~ 486 482 15 487.25 493.75 486 ~ 494 490 16 495.25 501.75 494 ~ 502 498 17 503.25 509.75 502 ~ 510 506 18 511.25 517.75 510 ~ 518 514 19 519.25 525.75 518 ~ 526 522 20 527.25 533.75 526 ~ 534 530 twenty one 535.25 541.75 534 ~ 542 538 twenty two 543.25 549.75 542 ~ 550 546 twenty three 551.25 557.75 550 ~ 558 554 twenty four 559.25 565.75 558 ~ 566 562 UHF â…¤ 25 607.25 613.75 606 ~ 614 610 26 615.25 621.75 614 ~ 622 618 27 623.25 629.75 622 ~ 630 626 28 631.25 637.75 630 ~ 638 634 29 639.25 645.75 638 ~ 646 642 30 647.25 653.75 646 ~ 654 650 31 655.25 661.75 654 ~ 662 658 32 663.25 669.75 662 ~ 670 666 33 671.25 677.75 670 ~ 678 674 34 679.25 685.75 678 ~ 686 682 35 687.25 693.75 686 ~ 694 690 36 695.25 701.75 694 ~ 702 698 37 703.25 709.75 702 ~ 710 706 38 711.25 717.75 710 ~ 718 714 39 719.25 725.75 718 ~ 726 722 40 727.25 733.75 726 ~ 734 730 41 735.25 741.75 734 ~ 742 738 42 743.25 749.75 742 ~ 750 746 43 751.25 757.75 750 ~ 758 754 44 759.25 765.75 758 ~ 766 762 45 767.25 773.75 766 ~ 774 770 46 775.25 781.75 774 ~ 782 778 47 783.25 789.75 782 ~ 790 786 48 791.25 797.75 790 ~ 798 794 49 799.25 805.75 798 ~ 806 802 50 807.25 813.75 806 ~ 814 810 51 815.25 821.75 814 ~ 822 818 52 823.25 829.75 822 ~ 830 826 53 831.25 837.75 830 ~ 838 834 54 839.25 845.75 838 ~ 846 842 55 847.25 853.75 846 ~ 854 850 56 855.25 861.75 854 ~ 862 858 57 863.25 869.75 862 ~ 870 866 58 871.25 877.75 870 ~ 878 874 59 879.25 885.75 878 ~ 886 882 60 887.25 893.75 886 ~ 894 890 61 895.25 901.75 894 ~ 902 898 62 903.25 909.75 902 ~ 910 906 63 911.25 917.75 910 ~ 918 914 64 919.25 925.75 918 ~ 926 922 65 927.25 933.75 926 ~ 934 930 66 935.25 941.75 934 ~ 942 938 67 943.25 949.75 942 ~ 950 946 68 951.25 957.75 950 ~ 958 954 In the radio spectrum, the frequency range of 48 ~ 958MHz is divided into five frequency bands. The frequency band I is for TV broadcasting channels 1 ~ 5, the frequency band II is allocated for FM broadcasting and communications, and the channel III is for TV broadcasting channels 6-12. The frequency band is 13 ~ 24 channels of TV broadcasting, and the â…¤ frequency band is 25 ~ 68 channels of TV broadcasting. Among them, channels 1 ~ 12 belong to "very high frequency band", commonly used in VHF; channels 13 ~ 68 belong to "ultra high frequency band", commonly used in UHF. It can be seen from the table that there is a certain interval between each frequency band of broadcast television, and these frequencies are allocated to applications such as FM broadcasting, telecommunications services and military communications. Radio and TV cannot be used for these frequencies, otherwise it will cause mutual interference between TV and other applications. However, since cable TV is an independent, closed system, as long as it is properly designed, it generally does not interfere with communication, so these frequencies can be used to expand the number of programs. See Table 07-03-5 for additional channel parameters in China. Table 07-03-5 Division of supplementary channels of China's cable TV Frequency band Channel Image carrier Sound carrier frequency frequency band Center frequency A1 1 112.25 118.75 111 ~ 119 115 2 120.25 126.75 119 ~ 127 123 3 128.25 134.75 127 ~ 135 131 4 136.25 142.75 135 ~ 143 139 5 144.25 150.75 143 ~ 151 147 6 152.25 158.75 151 ~ 159 155 7 160.25 166.75 159 ~ 167 163 A2 8 224.25 230.75 223 ~ 231 227 9 232.25 238.75 231 ~ 239 235 10 240.25 246.75 239 ~ 247 243 11 248.25 254.75 247 ~ 255 251 12 256.25 262.75 255 ~ 263 259 13 264.25 270.75 263 ~ 271 267 14 272.25 278.75 271 ~ 279 275 15 280.25 286.75 279 ~ 287 283 16 288.25 294.75 287 ~ 295 291 A3 17 296.25 302.75 295 ~ 303 299 18 304.25 310.75 303 ~ 311 307 19 312.25 318.75 311 ~ 319 315 20 320.25 326.75 319 ~ 327 323 twenty one 328.25 334.75 327 ~ 335 331 twenty two 336.25 342.75 335 ~ 343 339 twenty three 344.25 350.75 343 ~ 351 347 twenty four 352.25 358.75 351 ~ 359 355 25 360.25 366.75 359 ~ 367 363 26 368.25 374.75 367 ~ 375 371 27 376.25 382.75 375 ~ 383 379 28 384.25 390.75 383 ~ 391 387 29 392.25 398.75 391 ~ 399 395 30 400.25 406.75 399 ~ 407 403 31 408.25 414.75 407 ~ 415 411 32 416.25 422.75 415 ~ 423 419 33 424.25 430.75 423 ~ 431 427 34 432.25 438.75 431 ~ 439 435 35 440.25 446.75 439 ~ 447 443 Plug-In Connecting Terminals,Insulated Spade Terminals,Cable Connector Double Spade Terminals,Vinyl-Insulated Locking Spade Terminals Taixing Longyi Terminals Co.,Ltd. , https://www.longyicopperlugs.com
TV spectrum and channels