Dreambox DM 500S imitation in comparison with the original

Editor's note: low-priced receivers, and other equipment currently flooding the market, some people are also particularly love to buy low-priced goods, but they do not know why low-low price? As the saying goes a penny goods, the paper machine through analyzing DM500S imitation tell people, low-priced machine is the expense of the quality of access to low-cost, low-priced machine completely undermines the quality of prototype circuit security system, so use is not long a fault on the city. This low-cost, low quality products flooding the market, is China's satellite television reception equipment market tragedy.

Recently, the domestic TV circle is the most popular topic HD and DM500S. Since the beginning of some domestic factories copy imitation DM500S since domestic production copy DM500S sales price rapid decline in the number of its users also will be increased substantially.

DM500S the prototype is the dream of multimedia design and production of a television company, the company is also DREAM BOX series of set-top-box manufacturers, as we have known DM7000S, 7020S, 7025S models are its products. In the hardware we can DM500S as DM7000S the simplified, DM500S compared to DM7000 reduced after the panel the number of input and output physical interface, eliminating a PCMCIA module interface, front panel LCD display and built-in hard drive interface, and AC / DC external power supply, making the much smaller unit, but it functions with DM7000 is almost the same, both are basic operation similar.

We look at the official website DREAMBOX listed DM500S description:

-250 MHz IBM PowerPC processor (350 MIPS)
-- LINUX Operating System
-1 A smart card reader
-- MPEG2 hardware decompression
-- DVB-S
-- V.24/RS232 Interface
-100 MBIT two-way Ethernet Interface
2 LED instructions
-- An infinite number of TV / radio channel list
-- Channel conversion time of less than one second
-- Automatic scanning services
-- EPG (electronic channel guide)
-- Support DISEQC
-- Multilingual
-- Digital bitstream output S / PDIF interface (AC-3/DTS)
-1 - SCART (Europe interpolation)
There are some other technical indicators here no longer an exhaustive list, all digital satellite receiver now due conventional functions, DM500S all possess, but also with ordinary conventional satellite receivers do not have other functions. In short, DM500S is built-in Linux operating system, can also be called the party a built-in computer satellite receiver. It supports a variety of encryption systems and multi-server network sharing, do not like the Thunder 430 XP as different encryption system in the receiving signal switching system, can share the DV12 sharing does not need an external terminal. The encryption system can support a Seca, Viaccess, Irdeto, Viasat - NDS, Conax, Nagra1, Nagra2 etc., while supporting a variety of encryption systems Genuine card authorization. Genuine Descrambling can use the card to receive encrypted satellite TV signals, but also can network and CV12 same through sharing manner declassified. It also supports multi-satellite receiver, of course, picture quality than 430 such machines good. Other features also, through the network can be connected to a computer booking video. Not only can be connected to the TV watching, and through the network of computers within the LAN synchronous playback. Since it adopted the openness of the Linux operating system, so there are many third-party development teams are working against DM500 new, powerful application software development. We can believe, with all kinds of IMG and the development of plug-in succession, the machine can achieve more practical function.
Hands-depth understanding of the DM500S
We turn first to observe how the DREAM BOX DM500S set-top box hardware!
We have said earlier, DM500S size is very small, very exquisite workmanship appearance, except for the plastic front panel material, the rest of the chassis are a steel plate stamping molding. The overall appearance of a silver-gray, the front panel is white and silver gray-and streamlined design, coordination and looks natural. The left panel is DREAM multimedia LOGO, the following is the specific type logo, to the right is a smart card slot. The right side panel relatively simple, there is only one standby Dark red button and a small window, a small window infrared remote control receiver in the first and two LED indicators, the two were green LED power indicator instructions and a less remote control, red standby indicator.
DM500S the panel after the same simple: a LNB IF input and output of a LOOP in a group of composite video, the left-channel audio output terminal of the above is an RS232 serial port, mainly for the software updates; middle is a SCART (Eurostat interpolation) output, in addition to no other audio and video output interface. SCART (Europe interpolation) mouth, through the machinery of control menu can be output CVBS (composite video), S-VIDEO (light, color separation video), YCBCR (color), several different video signal; right followed by another S / PDIF digital audio output fiber, 12 V DC power input socket and LAN network line jack.
DM500S used iron chassis, the electromagnetic shielding of good, and the AC ADAPTER switching power supply external to further reduce the external electromagnetic interference is conducive to the sound, like the improvement of the quality, and improving long-term stability for the machines to work also played a useful role. It is precisely because of the external power supply and the reduction of hardware, makes the machine to further reduce the size,as the whole machine is within a block circuit boards.
Pai motherboard through the line connecting with the outside world only two, one is the front panel, and the other is the board behind the serial RS-232 upgrades, the two front panel is a power LED and touch standby switch, the red the remote control receiver in the first few connections, serial RS-232 upgrade only a DB9 socket. This shows that the structure of the machine is very tight.
The full picture of the entire circuit boards, circuit boards positive structured, the management function block boundary clear. According to the board, we all circuit functions of the 11 blocks. We will be in accordance with the understanding of the digital blocks respectively the main function.
Motherboard most striking largest IC POWERPC, this is the soul of the machine.
PowerPC is PerformanceOptimizationWith Enhanced RISC Performance Computing acronym is International Business Machines Corp. IBM devoted to the digital television decoder ASIC, chip tagging Digital Set - Top Box Integrated Controller, the sense that the management chips for digital set-top boxes. In the most chips can be seen beneath the specific models of the chip: IBM39 STB02500. STB02500 chip embedded PowerPC 405 microprocessor. POWERPC 405 is a high-performance, low-power CPU, the power consumption of less than 1 W, work speeds up to 252 MHz, the core is a 32-bit RISC CPU, the computation speed of 350 MIPS.
Motherboard blocks 2 and Block 3 are FLASH MEMORY and SDRAM.
FLASH MEMORY is a solid-state, non-volatile, replication of memory, its mode of operation is like random access memory and hard disk (HARD DISK) mixture. A durable, able to work under low voltage operation, as well as the power to shut down keeping data, and other functions. ); FLASH initial word from Toshiba because of the chip's ability to remove instant, from EPROM, and is gradually becoming a substitute for the EPROM. The DM500S used FLASH MEMORY is 4 M * 16BIT 64-BIT FLASH memory models is JS28F640J3D75 is Intel's products. It OS system for storing documents and IMG set up parameters and user data.
Dynamic memory is DRAM (Dynamic RAM) initials, SDRAM Synchronous DRAM is the acronym in English, translated into Chinese is the meaning of synchronous dynamic memory. From a technical perspective, synchronous dynamic memory (SDRAM) in the existing standards into synchronous dynamic memory control logic (a state machine), the use of a single system clock synchronization address all data and control signals. Use of SDRAM will enhance system performance, but also simplify the design, providing high-speed data transmission. Functionally, it's similar to conventional DRAM, and also need to set the clock. It can be said that SDRAM is an improvement of the structure of the enhanced DRAM. DM500S adopted two SDRAM, a 16 M * 16BIT SDRAM is the Hyundai brand, model: HY57V561620CT 6, another film 8 M * 16BIT SDRAM is the Samsung brand, model: K4S181632I - UT60. 16 M * 16BIT SDRAM for the system, another film 8 M * 16BIT SDRAM for decoding data cache.
Another positively gigantic on the Main Board of course is modular, DVB-S tuner of the (Block 4). This machine used ALPS tuner, the models is BSBE1 - 706A. It installed in a small circuit board. Small negative equipped with a circuit board used for the tuning voltage of 30 V step-up circuit, small plates and through a row of pins welded together with the motherboard. ALPS tuner major part of the RF tuner and QPSK demodulator composed of two parts, QPSK demodulator IC using ST's STV0299B, two parts of a circuit are packed in a shielding crust integration DVB-S tuner. Integration tuner quality merits, the decision to the overall quality and performance of digital receivers because it is the first gateway to prove that the actual use of the tuner performance is very stable, threshold is not too high, the only inadequacies of the heat is slightly larger than, perhaps with less space within the machine, cooling performance is obviously smaller than the chassis, that is, several things have an advantage there must be a disadvantage.
Block 5 is the system motherboard clock oscillator. It consists of a 27 MHz quartz resonator and a 74 HCU04 (U23) pose. Its output was sent to the chip U1 in the PLL, a hardware system for the whole of the clock frequency.
Motherboard block 6 is the machine part of the network interface. The region's largest chip is the size of the network interface chip, the model is AX88796 (U5), it is Taiwan ASIX Company introduced NE2000 compatible with Fast Ethernet controller, a 10/100 MBPS internal integration adaptive physical layer transceiver , and 8 K * 16BIT SRAM. In this chip , there are three micro-LED patch, D5, D6 and D7, which is not usually the light, only to insert this line of network interface cards, including the D6 and D7 will be normal luminous, and that this network is connected to normal, if the LAN installed correctly inside the aircraft, the plane that is as a computer terminal access network, the card at this time if DM500 through exchange of information D5 will be flashes and even within that network transceiver, communications normal.
In this region, there is a chip 8 feet (U3), the Model 93 LC66. 93 LC66 is a serial E? PROM, capacity is 256 * 16 BIT, with its memory card MAC address data. 93 LC66 and we are all familiar with the 24 LCxx E? PROM, but two different forms of data interface, 24 LCxx was I? C, and 93 LC66 is the SPI interface. SPI is the acronym Series Protocol Interface, which is a signal using four Serial Line Interface agreements, including master / slave two models. Four interface signals are:
MISO = serial data input (the device input, output from the equipment);

MOSI = serial data output (output main equipment from the equipment imported);

SCK = shift clock;

SS = from the equipment so that it can.

SPI interface is the most prominent characteristic of the equipment by the clock signal to define whether or not the appearance of Main / person communication between devices. Once detection equipment issued to the main clock signal, data transmission began, the clock signal void, the transmission ended. During this period, must be requested from the equipment so that it can (SS signal maintain effective). SPI is the only way the advantages of occupying four data sheets, data transmission speed.

Block 7 is the motherboard of the machine's audio D / A converter and the output buffer part. Audio D / A converter using the Taiwan Princeton's PT8200 (U10), this chip eight feet by the SOIC package, the working voltage 5 V, 16, and the right alignment data format audio D / A converters.
Audio output buffer using National Semiconductor's LM358 (U11), which is a dual-eight feet operational amplifier chips, and commonly used in the audio equipment in 4558 and NE5532, and other dual operational amplifier chip pin-compatible, but its very general audio indicators .

STB hardware system power are rather complex, the number of chips inside the aircraft to more group work regulator Power and DC-DC switching power supply two categories. DM500S use an external AC ADAPTER power supply, the input DC 12V to the corresponding DC / DC boost or buck circuit inside the aircraft to meet the requirements of various voltage. Block 8 is the board by 12 V voltage converted into 5 V and 3.3 V DC / DC switching power supply. The chip POWERPC and DVB-S tuner for 2.5 v, and 1.8 v by the LDO Linear Regulators LT1117 twice transform produce.

This machine 5 V and 3.3 V DC / DC switching power supply from two of ACT4060 (IC40, IC41) composition, IC40, L402, D42, and other components 3.3 V DC / DC power supply, IC41, L400, D40, and other component 5 V DC / DC power supply. ACT4060 maximum output current of 2A, the highest conversion efficiency of 95%, the input range of 4.75 to 20 V, adjustable output voltage range of 1.3 to 18 V, shutdown current 8 UA, switching frequency of 410 kHz work with the flow, short circuit, overheating protection and electrostatic characteristics, SOP -8 package.

Motherboard block 9 is the second LNB supply voltage converters part. We know that the LNB supply voltage of the receiver decision LNB polarization, the general standard for 13/18 V supply voltage, the voltage at the same time also, in its need for signal modulation 22 KHZ to control dual-LNB the vibration of the vibration and switching and DISEQC 22 KHZ IF switch.

DM500S the LNB supply voltage conversion of the second by LINEAR Technology, Inc. Model LT1930 step-up switching regulator (U70) and L711, D71, and other components constitute. LT1930 maximum output voltage of 34 V, input voltage range of 2.6 to 16 V, switching frequency 1.2 MHz.

Block 10 is DM500S the RS-323 interface, RS-232 interface level translation and driven by the SP3243 (U60) chip to complete. SP3243 is a three transmitter, five receiving end of the RS-232 transceiver, the general bias applied to mobile equipment and handheld devices such as laptops and hand-held computers. SP3243 includes a complementary receiver to a shutdown at its sustained mode detection equipment external trigger signal. SP3243 features can reduce the brightness of color video signal interference and electromagnetic interference, the data transfer rate can be as high as 1 MBPS high speed requirements, it can easily meet the RS-232 application requirements. SP3243 series of built-in high efficiency charge pump power supply, serving 3.3 V, and only a 0.1 UF external capacitance. SIPEX S charge pump and the driving structure makes SP3243 series can supply range +3.0 V to +5.5 V between work. Automatic Line feature SP3243 can be opened in the work of connecting equipment, automatic shutdown mode from the sedation. In addition, the SP3243 can also automatically enter the power consumption is less than 1 UA shutdown mode.

SP3243-pin, DM500S boot issued by the response when serial string.

DM500S serial port using full-duplex serial communication interface and the standard DB9 Interface connectors, transmission parameters: Baud Rate 115200 BPS, no parity bit, 8 bits, 1 stop bit.

Block 11 is the smart card reader clip, its data lines POWERPC direct access to the main data interface chip.

The DM500S comparison of different origin

1, DREAM BOX origin DM500
We know that DM500S is designed and manufactured by the DREAM BOX. So the original production DM500S with our hands What's the difference between copying machine?
Jurassic wish to thank Mr. and Shenzhen Jurassic gang Technology Limited, provided they gave the author a DM500S prototype, it gives us an opportunity see DM500S prototype on the international scene. DREAM BOS factory production DM500S (OEM BY CHINA), its motherboard. We can see that the aircraft using ALPS tuner the BSBE1 - 702A, the main power DC / DC power supply and LNB DC / DC were used Linear Technology Corporation (Linear Technology) LT1940 and LT1930; FLASH using Intel's TE28F640; two Tablets were used modern SDRAM and AMIC products; clock frequency of 136.5 MHz crystal, PLL is adopted MK2727; audio DAC is BB's PCM1725; original production DM500S all along using ALPS tuner, using PHILIPS the DM500S the tuner all the imitation (copy) machine.

Original DM500S and imitation DM500S some subtle differences that can be controlled.

We can see that the DM500S addition to the original network plug and chassis structure with a number of different copying machine, the best obvious difference between the two is the use of electrolytic capacitors and power inductors. And this is precisely affect system performance issue of the utmost key unit components. Copying machines are used ordinary tantalum capacitor (or aluminum electrolytic capacitors) and the cheap domestic power inductors, inductance on the power DC / DC converter output performance of more prominent.

Power inductor the inductance is a special, it has a square or circular I-shaped ferrite frame using different diameter enveloping the system from the paint, mainly used in DC / DC conversion circuits as energy storage devices. Apart from the general power inductor the inductance value of inductance parameters, there are the following two main parameters: current and maximum operating frequency.

We know that, apart from inductor the inductance parameter volume, but also an important parameters - quality factor Q, which refers to a particular frequency inductor in the AC voltage work, presented by the inductance its equivalent loss Resistance ratio. Inductor higher Q value, the smaller the loss, the higher the efficiency. The inductor quality factor and the level of the DC resistance wire coil, coil skeleton dielectric loss and Core, shielding enclosures caused by wear and tear and so on.
Now most of the core power inductors ferrite core is. The ferrite core is composed of a mixture of iron oxide magnetic metal oxide sintering. Manganese - zinc ferrite and nickel - zinc ferrite is a typical ferrite materials. Manganese - zinc ferrite with high permeability and high magnetic flux density characteristics, and in less than 1 MHz frequency, a low loss characteristics. Nickel - zinc ferrite with high impedance rate of less than a few hundred low permeability rate, and other characteristics, and higher than 1 MHz frequency also have lower loss. Domestic production of ferrite cores as formula, sintering process and cost constraints, and so on condition bound, its magnetic conductivity, the magnetic flux density and high-frequency loss with foreign products, and so there are some gaps. At the same time due to concerns over cost, the domestic manufacturers of power inductors power inductors domestic production of the work can not be very high frequency; domestic ferrite core of saturation magnetic flux density is not high, in order to prevent inductor core saturation, in the production of power inductors , the core needs of a large air gap, this will add to the magnetic flux leakage inductance interference. The inductance in the power flow during working DC current, or in the switching frequency AC current to DC current on the stack, a DC magnetization Core inevitable phenomenon, leading to the decline of inductance.
Domestic prices only power inductors similar foreign products prices 1 / 4 to 1 / 3.

Domestic imitation of DM500S used homemade power inductors, and the LT1940 a DC / DC converter, the frequency is 1.1 MHz. In this frequency of core domestic inductance of the power loss will be greatly increased, decreased inductance Q value, as well as the magnetic core rate of decline higher inductance values, making DC / DC converter output ripple high. At the same time, imitation of DM500S use a lot of second-hand remove DM500s components, such as Flash, SDRAM, and so on. All this makes the work of copying machines instability, failure rate is much higher than the original DM500S.

DM500 is a serialization of products, the suffix - S for satellite digital TV set-top boxes, - C Digital Cable TV set-top boxes, and - T is the terrestrial digital TV receiver. Three different suffix DM500 in the differences in hardware using only the tuner is different. Meantime - C and - T in terms of the two models, because of their RF signal input terminal without outward are provided with power, so the two models are not required to provide power from outside, so no need to install two models LNB satellite-specific components of the power supply.

We can see it LOGO below tagging model is: DM500C. Its antenna interface is 9.5 antenna jack, and the F-satellite terminal obviously different. DM500C internal photos, we can see that it is the tuner models: CU1216L / A, behind the tuner part of LNB supply all parts not installed. The rest of the hardware and DM500S identical.