What is the Difference Between EDTV and HDTV?

EDTV (Enhanced definition Television), namely enhanced definition television. The number of horizontal scanning lines is 500-700 lines, which mainly corresponds to the existing TV resolution level, and its image quality is studio level.

EDTV

EDTV, HDTV, SDTV explained

What is the difference between high-definition digital television (HDTV), enhanced digital television (EDTV) and standard-definition digital television (SDTV)?

HDTV is the abbreviation of English High Definition Television, which means high definition television. High-definition television must have at least 720-line progressive (720p) or 1080-line interlaced (1080i) scanning, a screen aspect ratio of 16: 9, and an audio output of 5.1 channels (Dolby digital format). Low-format signals are digitized for playback.

EDTV is the abbreviation of English Enhanced Definition Television , which means enhanced definition television. The TV is required to have at least 480 line progressive (480p) scanning, and the audio output is in Dolby Digital format.

SDTV is the abbreviation of English Standard Definition Television , which means standard definition television. The TV is required to have at least 480 line interlaced (480i) scanning. This standard is the minimum standard for HDTV standards.

HDTV, EDTV and SDTV distinguish the ability of digital televisions to reproduce digital television broadcast signals of various picture qualities. Television stations can use any of the 18 picture formats in the ATSC digital television standard to broadcast digital television programs. High Definition Television (HDTV) can receive all ATSC 18 digital television picture formats and use interlaced The scanning method of 1080 scanning lines (1080i) or sequential 720 scanning lines (720p) reproduces the original quality of high-definition digital television (HDTV) programs, and does not degrade high-quality program signals for broadcast. Enhanced Definition Digital Television (Enhanced Definition Television, EDTV) can receive all ATSC 18 digital TV picture formats, and display the program picture in a sequential 480 scan line (480p) scanning mode. Standard Definition Digital Television (SDTV) can receive all ATSC 18 digital TV picture formats, and broadcast all 18 using the same interlaced 480 scan line (480i) scanning method as existing analog TV Different picture formats. This means that the quality of digital TV programs originally broadcasted in high-definition is greatly reduced to match the quality of the TV's 480 scan lines.

Take the Huawei eDTV TV box as an example.

Huawei eDTV TV box can be operated through the front panel and remote control. It has a picture mode menu function and supports translucent OSD (OnScreenDisplay) function. The menu is multi-language version, and products sold in China will naturally join the full Simplified Chinese version. Chinese or Traditional Chinese menus make it very convenient for everyone to use.

Huawei eDTV TV box not only has excellent picture, but also can adjust the picture proportion, with three modes of 16: 9, 4: 3, Center, it also supports noise suppression function, through various fine adjustments, you can achieve better results ; It is also very easy to search and manage TV channels, and it provides a blue display protection screen function, which can prevent the LCD screen from making sounds when scanning or switching channels. Huawei eDTV TV box can be connected to a computer's sound card and graphics card, monitor, AV and S-terminal video input and other devices at the same time, and switch freely. It is worth mentioning that it not only supports 1024 * 768 @ 75Hz (1024 * 768 @ 85Hz in hidden mode), but when switching to a PC screen, although other TV boxes often have problems such as flickering, etc., and The effect of directly connecting the graphics card to the monitor is far from good, but the Huawei Wei eDTV TV box is much better. At first glance, you can see almost no difference.

When receiving and displaying TV programs, the biggest feature of the eDTV TV box is that it can convert a 50Hz TV signal to 60Hz or even 75Hz (PAL). In this way, the picture feels much better, and it uses a monitor Watching TV, even if watching TV or other video content for a long time, will not be so tired.

Design structure and technology of eDTV TV box

We opened the eDTV TV box and found that it has a radiation-proof steel plate, which can effectively reduce radiation.

In many aspects of the design of the Huawei eDTV LCD TV box, the ATI graphics card is used. It uses a four-layer PCB board and is neatly constructed, and all its components are the highest grade in the TV box.

The design of Huawei's eDTV LCD TV box is quite mature and stable. There have been 12 revisions of this model. When it is officially launched, it will be a version of REV14 or more.

This eDTV TV box uses Philips TV's FQ1216ME / IH, which is the same as many common TV receivers, such as ALL in Wonder Radeon / ALL in Wonder Radeon 7500. Dozens of types of Philips radio heads are used on a variety of different devices, occupying most of the market together. Philips tuner is used to receive and tune the TV signal, which has a direct relationship with the TV effect. At present, Philips tuners are mainly divided into two categories: DVB (Digital Video Broadcasting) and ATV (Analog TeleVison). Among them, DVB tuners mainly include these types: wired Internet tuner (mainly used on DVB-modem), Satellite digital tuner (mainly used on DVB-S), wired digital tuner (mainly used on DVB-C), terrestrial digital tuner (mainly used on DVB-T and HDTV), and ATV-type tuner It mainly includes two types of full-frequency TV tuner and horizontal video tuner. Full-frequency TV tuner is mainly used on TV, and horizontal video tuner is one of the most widely used tuner, CAR-TV, DVR It is often used on devices, LCD TVs, PC-TVs, and multimedia cards. Such products from Philips are mature and stable, so they have been widely used and have been used for many years. The programmable chip tuner used on the ALL in Wonder Radeon 8500DV is more advanced and has better performance than these analog tuner. The price is high, and the heat generation is large. When it is used on a TV box, it will inevitably increase the price and heat generation (the eDTV LCD TV box already has a source of heat). A Philips horizontal video tuner. Therefore, it is very appropriate for the Huawei eDTV LCD TV box to use this tuner, and the officially launched products also use the FI1256MK2 / I tuner (this is a sample), which adds support for the D / K system. Take all PAL system, use TDA5736M + TSA5523 + TDA9800T chip, also VST + PLL + VIF frequency synthesis, input frequency is 49.75-863.25MHZ.

Although relatively cheap, the tuner still accounts for a large proportion of the total cost of the TV card / TV box. Therefore, many TV cards / TV boxes often use cheap non-dedicated tuner. At the same time, the cost and price are reduced. Performance has shrunk.

Warwick eDTV LCD TV box uses Winbond W27C010P-70BIOS, which can be rewritten and upgraded. A 32-bit DSP (digital semaphore processor) processor is installed next to the BIOS. Samsung S3P84554XZZ DSP processor may be used on the official product. Nowadays, a system composed of a DSP (digital signal processor) and a general-purpose processor is a very common design, which can achieve high working efficiency, so it is widely used, and the DSP processor has become one of the most sold processor varieties. This DSP processor from Samsung has a single function and is useless alone, but its excellent computing power enables it to do a good job as an assistant and play an important role in this TV box.

Huawei eDTV LCD TV box uses a lot of filter capacitors. Among the capacitors, there is a Pucheng PT2313L, which is a four-channel sound processing chip responsible for processing sound, with high and low bass control, loudness control, independent mute and other functions. PT2313L uses I2C control interface, 20-pin SSOP package, and the pin definition is the same as the original TDA7313 and can be interchanged. Its performance is good, the distortion rate and noise are very low, the volume attenuation rate is only 1.25dB / level, plus With the help of Samsung DSP processor, the sound is a good configuration in the TV box.

Big pieces are out! This is the core part of Huawei's eDTV LCD TV box: Trident DPTV-DX chip, Samsung DSP processor is mainly to give it a hand. The performance of DPTV-DX, which is not high or low, is not as good as professional level, but it is the strongest equipment in amateur equipment such as TV boxes! Since the failure of the graphics card market, Trident has become more focused on the development of TV products. DPTV-DX is Trident s proud work. It is a powerful quasi-high-definition graphics processing chip. Its full name is Digital Process TV. The most important function is the frequency modulation of TV signals, which is not different from similar products. However, in the processing of Digital TV and video signals, almost no other similar products can match Trident's DPTV series. Since the advent of DPTV chips in 1999, TV manufacturers have adopted DPTV one after another. Nowadays, the strong players in the domestic appliance industry, such as Konka, TCL, Changhong, Hisense, and Skyworth, have adopted DPTV series chips on their high-end products. With the powerful performance of DPTV series chips, these domestic color TVs can already reach the same or even more advanced technology level than the Japanese high-end color TV GiGa series of Panasonic. At present, more than 70% of domestic frequency conversion and progressive scanning color TVs use DPTV chips, and the Huawei Wei eDTV LCD TV box, which also uses DPTV chips, has the same strong performance.

How good is the DPTV chip? This is very complicated to say, and it is not necessary at all, because what we are mainly talking about is a TV box, and there are so many other things involved, it may be suspected of defrauding fees. In simple terms, it is that all other TV chips have all the functions, and there are other original functions, and the performance is stronger than other TV chips, which are summarized as follows:

1. Digital processing of TV signals;

2. Dynamic detection type picture, with progressive scanning function, effectively eliminate line structure line and line jagged, and also have video compensation function, effectively reduce the jagged generated in motion, which is the main strength of DPTV ;

3. Digital dressing filter, strong color reproduction ability, high definition, and good picture quality;

4. Unique and complete functions;

5. Easy to install and use, and can run completely away from the PC, you can watch TV programs even when the PC is off;

6. Attractive price;

The DPTV-DX chip is under the silver-white heat sink in the Huawei eDTV LCD TV box, and it generates a lot of heat.

Huawei eDTV LCD TV box uses SDRAM static cache and reserves LBC port. It uses four modern 7ns particles with a total capacity of 8M. Although it is not comparable to a graphics card, it is already luxurious compared with other TV boxes that generally have only 1,2M cache, so it can be smoother. Processes video streams and enables some advanced features.

Huawei's eDTV LCD TV box can automatically tune up to 125 channels, and its channel scan uses a 9-grid window to display the preview screen, which is intuitive and unique.

I tested the Huawei eDTV LCD TV box in both wireless and wired modes. In wireless mode, although it is not connected to an antenna, it can still receive programs from nearly twenty television stations. The following is the TV screen in wireless mode. The text is abstract, let's take a look at the actual picture of watching TV.

Although the signal is not ideal, the effect of watching the TV on the Huawei eDTV LCD TV box is still good. The picture is clear and the colors are natural.

After connecting the cable TV antenna, the Huawei eDTV LCD TV box can receive 57 channels of TV programs (this is related to the region and time period). The above is the TV picture when the cable TV antenna is connected. The TV at this time The picture is more excellent, no noise and other noise, the picture is clear and pure, and the color is very good. Even in some other TVs and TV boxes, the most difficult transition colors and skin colors, it can perform quite well. Moreover, apart from these, the screen does not flicker.

Many color generation methods are based on the principle of three primary colors, that is, using red, green, and blue as the basic colors. Any other color can be realized by combining these three colors according to different proportions. So to transmit a color image, you can actually only transmit Images in these three colors. However, one of the fatal weaknesses of this transmission method is that it is not compatible with black and white TVs, because black and white TVs are TV signals with only a change in brightness, so a successful color TV system must also transmit brightness signals at the same time. The relationship between the luminance signal and the three primary colors is as follows:

Y = 0.30R + 0.59G + 0.11B (1)

Among them, Y is a brightness signal, and R, G, and B are red, green, and blue light signals, respectively.

After transmitting the luminance signal, to realize the color image, it is no longer necessary to transmit the three-color optical signals. Considering the relationship between the luminance signals and the three-color optical signals, it is only necessary to transmit two independent variables. Already.

| 0.30 0.59 0.11 || R | | Y |

| 1 0 0 || G | = | R |

| 0 0 1 || B | | B |

After transformation:

| 0.30 0.59 0.11 || R | | Y |

| 0.70 -0.59 -0.11 || G | = | RY | (2)

| -0.30 -0.59 0.89 | B | | BY |

Among them, RY and BY are called color difference signals, and they are two independent variables.

This matrix is called a transmission matrix, and it shows how the three-color signal obtained by the camera becomes the transmitted brightness and color difference signals, and it is also the basis for how the received brightness and color difference signals are reduced to three chrominance signals.

Regarding the transmission of luminance signals, black-and-white TVs have been specified. In order to maintain compatibility with black-and-white TVs, this set can only be copied. Therefore, the research of the color TV system is mainly on how to transmit two color difference signals. According to the regulations of black and white TV, the brightness signal is a wideband signal, so the color difference signal can only be a narrowband signal. The three current color TV systems use a subcarrier at the high-frequency end to transmit two color-difference signals, but the transmission methods are different.

For the NTSC system, a balanced quadrature amplitude modulation system is used. This is to use two color difference signals to modulate the subcarriers of the same frequency but with a phase difference of 90 degrees, so that two color difference signals are transmitted using one subcarrier. From the concept of the NTSC system, in order to save the subcarriers, the two subcarriers modulated by the two color-difference signals are strictly out of phase by 90 degrees. This puts forward harsh requirements for the phase distortion of the entire transmission process. Generally, the phase distortion of the entire system is less than 12 degrees. In order to overcome the disadvantages of phase sensitivity in the NTSC system, increase the phase error tolerance during transmission, and reduce the requirements on the transmission system, PAL system and SECAM system have appeared.

The PAL system inherits the principle of linear matrix coding and high-frequency mixing of the NTSC primary color signals. It uses the NTSC system's spectral interleaving, quadrature balanced modulation and synchronous demodulation technology. The color information of adjacent rows is approximately the same vertical correlation. The transmitting end inverts the redness signal components line by line. When demodulating at the receiving end, the chrominance signals of adjacent lines are averaged, thereby improving the phase sensitivity of NTSC. Through these measures, the fixed phase error tolerance has been expanded, and the differential phase error and multipath reception error have been improved.

SECAM uses progressive transmission of red and blue difference signals, while changing the modulation of the color difference signal to the carrier from amplitude modulation to frequency modulation. Through these improvements, the margin of the differential phase is extended by 40 degrees.

The signal characteristics of the three systems are as follows:

TV system NTSC PAL SECAM

Scan lines 525 625 625

Field frequency (Hz) 59.94 50 50

Chrominance signal modulation mode Quadrature dual-phase modulation Quadrature dual-phase progressive phase-sequential frequency modulation

Color subcarrier frequency (MHz) 3.58, 4.43 4.43 4.25, 4.0625

The differences can be summarized as:

1. The chrominance signal modulation method (coding method) and the color subcarrier frequency are different.

2. The synchronization signal system, that is, the number of scanning lines, the field frequency is not consistent.

The chrominance signal modulation method and the color subcarrier frequency conversion are realized through decoding / coding mode, that is, according to the input of the television signal of different standards, it is first solved by the corresponding color television decoding electrical circuit, G, B, (or Y, U, V,) signals, and then use the corresponding color TV coding circuit to form signals that meet the required standards according to the required output signal format. Analog circuits can be used to accomplish this conversion.

The conversion of the synchronization signal system (number of scanning lines, field frequency) is a digital system conversion. Since 625 lines of the PAL system are 100 lines more than 525 lines of the NTSC system, one line is added for every 5 lines of the TSC system to form 6 lines. PAL system signal. The spatial correlation of the image can be used, and the weighted calculation method is used for internal tea. Since the field frequency of the PAL system is 0Hz and the field frequency of the NTSC system is 59.94Hz, therefore, every 6 fields of the NTSC signal should generate 5 fields of the PAL signal. That is to say, every 6 fields of NTSC signals generate 5 fields of PAL signals, that is, one field is lost every 6 fields, and multiple images can be stored for weighting calculation. The Huawei eDTV TV box uses this principle to change the refresh rate. This looks simple, but in the past TV boxes often did not have this capability. With the Huawei eDTV TV box with a suitable display, the TV effect is still true TV. On board.

EDTV vs HDTV

Confused by EDTV vs HDTV? We don't blame you. The number of acronyms floating about with regard to digital TV is frightening. What's even more worrying is that very often they are used by people who have little or no knowledge about what they mean . If the person selling you doesn't know the difference between EDTV vs HDTV, how are customers supposed to decide which TV or projector to go for?

In our guide below, we've tried to distill the technical info into as few words as possible and make it as straightforward to understand as we can.

To properly explain EDTV vs HDTV, we need to step back a bit. Traditional TV has 525 lines of video which are interlaced. Interlacing just means that every frame of video is split into two fields and each field is shown alternately. Although there are 525 lines in the signal, only 480 lines contain video, so it is sometimes referred to as 480i (480 lines interlaced). This is known as Standard Definition TV, or SDTV. While this has worked well enough for fifty years, as TV sets have got bigger and projectors more popular, the quality deficiencies have become increasingly apparent.

The ultimate answer to improving the quality of the image displayed on your TV is HDTV, however, as a step on the road to HDTV, the industry came up with Enhanced Definition TV, or EDTV. This system contains the same 480 lines as SDTV, but they are progressive scan. Hence EDTV is also known as 480p. Progressive scanning just means that instead of splitting the signal into two fields and showing half the lines at a time, all 480 lines of video are shown at once. This results in a noticeable improvement in the quality of video.

The bad news in relation to EDTV vs HDTV is that you need a completely new TV or projector to display both EDTV and HDTV. Most DVD players on the market today are progressive scan, meaning they output EDTV signals, however, in order to view the progressive scan picture in all its glory, you need a TV or projector capable of displaying it and that, unfortunately, means getting a new TV.

In terms of content, there is very limited TV content available in HDTV format, and there is still wrangling about the standard for HD DVDs. However, every DVD disc on the market can be displayed in EDTV right now.

Bottom line? Pretty much every HDTV projector or TV on the market today will display EDTV as well. So even if you live in a country or area where HDTV content is limited or non-existent, it is worth it to watch your DVD collection in EDTV, the difference between SDTV and EDTV really is that big.

Kenny Hemphill is the editor and publisher of The HDTV Tuner-a guide to the kit, the technology and the programming on HDTV.