1. Analog signal format
Wiki describes it like this: "The color video signal is a linear combination of the luminance of the picture, and a modulated subcarrier carries the chrominance or color information, a combination of hue and saturation.". In other words, the so-called color analog TV is actually realized by having black and white pictures and then "coloring" (chrominance is chrominance information, abbreviated as C; luminance is brightness information, abbreviated as Y). The colors are composed of three basic colors, RGB (red, green, blue). Therefore, it seems that transmitting a color analog TV signal requires 4 analog signals to be transmitted (each variable has a corresponding sensor to collect, including light sensing, sensing red, sensing blue, sensing green; and then If the sound signal is added, there are 5 signals). In fact, when the TV system transmits, only one cable is used to transmit these signals, which is also called Composite Video. This is the meaning of the existence of the following standards; and similarly, the biggest difference between the following three TV systems is also The mechanism for loading color information is different.
2. PAL
PAL, is the abbreviation of Phase Alternating Line. PAL is a color television transmission protocol developed to solve the problem of loss of chroma in the case of NTSC format signals. PAL is authentic German made.
PAL uses QAM (quadrature amplitude modulation) to carry chrominance information. It adds a sub-carrier (4.43361875 MHz), and uses the red signal and the blue signal as the two baseband signals of QAM, so as to realize the transmission of chrominance information on the original black and white cables. Need to explain the choice of this carrier frequency, you can also find some information we need. The wiki explains “The 4.43361875 MHz frequency of the colour carrier is a result of 283.75 colour clock cycles per line plus a 25 Hz offset to avoid interferences. 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. "This 50 Hz is the frequency at which the screen is updated during playback, that is, the actual playback frame rate is 50 frames per second. Why is it 50 Hz? It also involves a concept called Interlaced video. This technique repeats each frame of the picture once, so that 25 frames of video signal is played out with the effect of 50 frames; it can be seen that if the cables and equipment are very powerful, our analog color TV is already quite clear. Unfortunately, the simulated equipment is not so easy to do.
In addition, it is worth mentioning that the wiki has another description: "The term PAL is often used informally and somewhat imprecisely to refer to the 625-line/50 Hz (576i) television system in general, to differentiate from the 525-line /60 Hz (480i) system generally used with NTSC.” As you can see from the description, in actual implementation, using PAL means that the TV program is 625 lines, and NTSC means that the TV program is 480 lines. This is what we often call the clarity of analog TV. At the same time, a guess, the traditional analog TV signal transmission equipment is also designed according to these two definitions, then, here will be the bottleneck of the analog video signal.
Mainland China uses the PAL-D analog color television protocol.
3. NTSC
NTSC, is the abbreviation of National Television System Committee. This is the earliest color TV agreement, but it appeared in South America. Perhaps this is one of the reasons for the emergence of the other two European agreements.
NTSC uses the same modulation technique as PAL to add chrominance information. But the sub-carrier frequency that carries chrominance information is 3.579545 MHz. In addition, the biggest difference between it and PAL is that the processing of chrominance information is different. You can refer to the wiki for details, and the explanation is a bit annoying.
NTSC transmits a video signal of 30 frames/s, and the actual picture update frequency is 60 Hz. It is also the case of "horse butt determines the width of the rails". The update frequency of the LCD monitors we use is mostly 60 Hz. Of course, some over-energy LCD manufacturers are also producing higher-frequency displays, but that has to wait for other hardware to keep up.
4. SECAM
SECAM is the abbreviation of French Séquentiel couleur à mémoire, and the wiki explanation is "Sequential Color with Memory". The emergence of SECAM is said to also make up for the shortcomings of NTSC. However, the approach taken by SECAM is different from the previous two. It adds an extra signal (using FM modulation) to transmit chrominance information on the basis of the original black-and-white TV. So, how does it use one FM to bring two color signals? I have to say that their design is relatively clever. The system uses an analog delay circuit to transmit the color information sent at the previous moment, so that two colors can be played at the same time. This is also the meaning of sequential and memory in its name. . but. . . It looks so complicated, but I don’t know how it will be implemented.
Anyway, I didn't see a word in the security camera, it was like this. It is said that it is still in use.
5. Other interfaces or transmission mechanisms
For the other interfaces here, the biggest difference between the above three transmission methods is that the above three are all transmitting Y and C on the same line, that is, Composite Video, while the other methods are mostly Component Video. Component Video uses Seprate Video (S-Video), YPbPr and RGB. Among them, S-Video is the S-video we often say, YPbPr is the S-video we often say, and RGB is the signal transmitted by the VGA interface of our TV monitor (there are other signals on the VGA).
Seprate Video is mainly to solve the problem of mutual interference when the Y signal and C signal are transmitted on the same cable. Therefore, it is only a simple transmission of Y signal and C signal with two wires. In this way, the interference is eliminated, and the transmission effect is naturally better. S-Video transmission cables usually use Din-connector cables or coaxial cables with a pair of BNC connectors.
YPbPr is calculated from the RGB signal. Among the three wires, the Y signal is also a luminance signal, while Pb is Blue-Y, and Pr is Red-Y. This is mainly because there is the relation Y = 0.2126 R + 0.7152 G + 0.0722 B. In this way, the difference between the Green signal and Y is not big, and the color can be restored better by transmitting the difference between the two outside two and Y. The YPbPr signal can be transmitted with RCA connector cable, or 3 and BNC connector coaxial cable.
6. Digital Video Signal
From the point of view of the data source, the data provided by the digital system is essentially 01 sequence, which is a huge difference from the analog system using different channels to carry multiple variables. After a large number of semiconductor devices are used, regardless of the size of the hardware or the complexity of the hardware, the 01 sequence transmission is relatively easier than the transmission of multiple subcarriers.
Digital video is divided into high-definition video (HDTV) and standard-definition video (SDTV) according to its definition. There is no clear distinction between the two concepts, but there are also some vague distinctions. In fact, 1280x720 (720P), interlaced1920x1080 (1080i), 1920x1080 (1080P), etc. are usually called HDTV; lower resolutions, such as 640x480 (NTSC equivalent resolution), 720x480 (NTSC, 16:9), 720x576 (PAL equivalent resolution) These are usually referred to as standard definition televisions. In actual use, TV service providers have reduced the resolution to save bandwidth and reduce the difficulty of operation. Therefore, the so-called high-definition and standard-definition are the result of "shrinking".
In addition, many of the digital data used for transmission are compressed. Among them, the most widely used digital video formats include H.261, H.263, H.264 (part of MPEG-4 powder) and other compression codes established by the ITU, as well as Microsoft's WMV and Apple's Quick-Time. . These ITU formats are all designed for digital video calls. At the same time, H.264 is also widely used in digital TV, IPTV, and network video.
Since the digital video data are all 01 sequence, the digital video transmission only needs a reliable digital transmission channel provided by the transmission system (of course, delay and packet misordering are also quite important transmission factors), and the video data can be transmitted. In current applications, the following transmission mechanisms for digital video have received widespread attention.
7. Digital TV
Of course, digital TV is still transmitted in the original analog TV network, such as using coaxial cable, satellite, microwave and other media.
Compared with the analog TV system, the digital TV system not only makes it easier to transmit high-quality pictures, but also saves a large part of spectrum resources. In many areas, computer systems have been digitally upgraded, and the saved frequency resources have been used to provide some other services.
Digital TV protocols have appeared and have been adopted: Advanced Television System Committee (ATSC), igital Video Broadcasting-Terrestrial (DVB-T), Terrestrial Integrated Services Digital Broadcasting (ISDB-T), Digital Terrestrial Multimedia Broadcasting (DTMB) The digital TV in our country uses the DTMB digital TV system.
8. IPTV
With the popularity of the Internet and the increase in network bandwidth, IPTV has become the new favorite of operators and content providers in recent years.
IPTV is a networking method based on TCP/IP (IP, Internet Portocal). Video data is transmitted in a stable channel constructed by TCP/IP. This kind of TV network basically does not depend on the physical network, it only needs to be connected to the Internet. IPTV uses the IGMP snooping protocol at the IP layer to transmit video streams within a specified range; at higher layers, UDP and RTP protocols are more commonly used.
As for Internet access, it is more popular through the underlying Ethernet, ADSL, and xPon networks. Depending on the access network, it is possible that the cable connected to the home equipment may be power line, twisted pair, telephone line, wireless or optical fiber.
There are other transmission systems based on TCP/IP. Their principles are similar to those of IPTV, so I won’t repeat them.
Some VOD implementations are also similar to IPTV, but there are also quite a few VOD systems that combine IP networks and analog technologies.
9. Other digital video interfaces
These interfaces are generally used for connection between devices, rather than long-distance video transmission. Therefore, a larger part of these interfaces directly transmit uncompressed video information, such as HDMI, DVI, YCbCr, etc.
Among them, the HDMI and DVI interfaces are familiar to everyone, so I won't repeat them. What needs to be mentioned is that DVI can also be configured to transmit analog signals, or both analog and digital can be transmitted together. This is a bit different from what we generally recognize.
YCbCr is the digital version of YPbPr, which is just one for transmitting digital signals and the other for transmitting analog signals. But the calculation process of YCbCr seems to be a little bit more complicated. It also uses RCA cable, a universal RCA cable.
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How far(long) the transmitter cover?
The transmission range depends on many factors. The true distance is based on the antenna installing height , antenna gain, using environment like building and other obstructions , sensitivity of the receiver, antenna of the receiver . Installing antenna more high and using in the countryside , the distance will much more far.
EXAMPLE 5W FM Transmitter use in the city and hometown:
I have a USA customer use 5W fm transmitter with GP antenna in his hometown ,and he test it with a car, it cover 10km(6.21mile).
I test the 5W fm transmitter with GP antenna in my hometown ,it cover about 2km(1.24mile).
I test the 5W fm transmitter with GP antenna in Guangzhou city ,it cover about only 300meter(984ft).
Below are the approximate range of different power FM Transmitters. ( The range is diameter )
0.1W ~ 5W FM Transmitter ：100M ~1KM
5W ~15W FM Ttransmitter : 1KM ~ 3KM
15W ~ 80W FM Transmitter : 3KM ~10KM
80W ~500W FM Transmitter : 10KM ~30KM
500W ~1000W FM Transmitter : 30KM ~ 50KM
1KW ~ 2KW FM Transmitter : 50KM ~100KM
2KW ~5KW FM Transmitter : 100KM ~150KM
5KW ~10KW FM Transmitter : 150KM ~200KM
How to contact us for the transmitter?
Call me +8618078869184 OR
Email me [email protected]
1.How far you want to cover in diameter ?
2.How tall of you tower ?
3.Where are you from ?
And we will give you more professional advice.
About Us
FMUSER.ORG is a system integration company focusing on RF wireless transmission / studio video audio equipment / streaming and data processing .We are providing everything from advice and consultancy through rack integration to installation, commissioning and training.
We offer FM Transmitter, Analog TV Transmitter, Digital TV transmitter, VHF UHF Transmitter, Antennas, Coaxial Cable Connectors, STL, On Air Processing, Broadcast Products for the Studio, RF Signal Monitoring, RDS Encoders, Audio Processors and Remote Site Control Units, IPTV Products, Video / Audio Encoder / Decoder, designed to meet the needs of both large international broadcast networks and small private stations alike.
Our solution has FM Radio Station / Analog TV Station / Digital TV Station / Audio Video Studio Equipment / Studio Transmitter Link / Transmitter Telemetry System / Hotel TV System / IPTV Live Broadcasting / Streaming Live Broadcast / Video Conference / CATV Broadcasting system.
We are using advanced technology products for all the systems, because we know the high reliability and high performance are so important for the system and solution . At the same time we also have to make sure our products system with a very reasonable price.
We have customers of public and commercial broadcasters, telecom operators and regulation authorities , and we also offer solution and products to many hundreds of smaller, local and community broadcasters .
FMUSER.ORG has been exporting more than 15 years and have clients all over the world. With 13 years experience in this field ,we have a professional team to solve customer's all kinds of problems. We dedicated in supplying the extremely reasonable pricing of professional products & services. Contact email : [email protected]
Our Factory
We have modernization of the factory . You are welcome to visit our factory when you come to China.
At present , there are already 1095 customers around the world visited our Guangzhou Tianhe office . If you come to China , you are welcome to visit us .
At Fair
This is our participation in 2012 Global Sources Hong Kong Electronics Fair . Customers from all over the world finally have a chance to get together.
Where is Fmuser ?
You can search this numbers " 23.127460034623816,113.33224654197693 " in google map , then you can find our fmuser office .
FMUSER Guangzhou office is in Tianhe District which is the center of the Canton . Very near to the Canton Fair , guangzhou railway station, xiaobei road and dashatou , only need 10 minutes if take TAXI . Welcome friends around the world to visit and negotiate .
Contact: Sky Blue
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English: We accept all payments , such as PayPal, Credit Card, Western Union, Alipay, Money Bookers, T/T, LC, DP, DA, OA, Payoneer, If you have any question , please contact me [email protected] or WhatsApp +8618078869184
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Pay by Western Union to me :
First name/Given name: Yingfeng
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Full name: Yingfeng Zhang
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T/T . Pay by T/T (wire transfer/ Telegraphic Transfer/ Bank Transfer)
First BANK INFORMATION (COMPANY ACCOUNT):
SWIFT BIC: BKCHHKHHXXX
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Account Name : FMUSER INTERNATIONAL GROUP LIMITED
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Second BANK INFORMATION (COMPANY ACCOUNT):
Beneficiary: Fmuser International Group Inc
Account Number: 44050158090900000337
Beneficiary's Bank: China Construction Bank Guangdong Branch
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Address: NO.553 Tianhe Road, Guangzhou, Guangdong,Tianhe District, China
**Note: When you transfer money to our bank account, please DO NOT write anything in the remark area, otherwise we won't be able to receive the payment due to government policy on international trade business.
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* It will be sent in 1-2 working days when payment clear.
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* If the packages is below 2kg,we will be shipped via post airmail, it will take about 15-25days to your hand.
If the package is more than 2kg,we will ship via EMS , DHL , UPS, Fedex fast express delivery,it will take about 7~15days to your hand.
If the package more than 100kg , we will send via DHL or air freight. It will take about 3~7days to your hand.
All the packages are form China guangzhou.
* Package will be sent as a "gift" and declear as less as possible,buyer don't need to pay for "TAX".
* After ship, we will send you an E-mail and give you the tracking number.
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For Warranty .
Contact US--->>Return the item to us--->>Receive and send another replace .
Name: Liu xiaoxia
Address: 305Fang HuiLanGe HuangPuDaDaoXi 273Hao TianHeQu Guangzhou China.
ZIP:510620
Phone: +8618078869184
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