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. Therefore, these frequencies can be used to expand the number of programs. This is an additional channel in the cable TV system.
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 |
433mhz Antenna Description
The 433MHz scuker antenna has beautiful appearance, convenient installation, wide frequency range, good performance, has receive a steady, anti salt fog corrosion resistance, anti-jamming, the antenna is arranged at the bottom of the magnet can be adsorbed in the car, easy to use.
433Mh Antenna is a kind of medium gain mobile antenna specially designed for communication system. Using the stainless spring material, the antenna features nice appearance and easy installation.
433Mhz Antenna Specifications
Frequency range :433MHz
VSWR :≤ 1.2
Gain: 2.5dBi
Polarization: Vertical
Maximum input power: 50W
Impedance: 50
Cable type: RG174
Length: 3M
Connector: SMA Male
433Mhz Antenna Picture
433mhz Antenna
433mhz Antenna,Wireless 433Mhz Antenna,Quality GSM Antenna,Onmi Directional 433mhz Antenna
Shenzhen Yetnorson Technology Co., Ltd. , http://www.yetnorson.com