A decoder is a hardware/software device that decodes and restores a digital AV data stream into an analog AV signal. Like video mpeg4, audio mp3, ac3, dts, etc. these can compress the original data storage, but this is also a commonly used encoding format, there are some professional encoding formats, the general family basically will not use. In order to reproduce this video and audio on a home device or computer, decoding software is required, commonly referred to as plug-ins. For example, mpeg4 decoding plug-in ffdshow, ac3 decoding plug-in ac3flir and so on. Only your computer with various decoding plug-ins can play these images and sounds. In terms of multimedia, the encoder mainly compresses the analog AV signal into a data encoding file, while the decoder converts the data encoding file into an analog AV signal.
<h1 class="pgc-h-arrow-right" data-track="2" > the decoder's functionality</h1>
To read and clear fault codes:
Some decoders have a more detailed description of the fault code, such as whether it is a historical fault code or a current fault code, and the number of times the fault code appears several times. If it is a historical fault code, it means that the failure occurred earlier. Nowadays, it does not appear, but there is a certain storage memory in the control unit ECU. The current fault code indicates that it is a failure, and through the number of occurrences to determine whether this fault code appears frequently, most of the current fault codes have a lot to do with the system failures that occur today.
Actuator actuation test function:
We can use the decoder to some actuators, such as injectors, idle motors, relays, [5] solenoid valve cooling fan, etc. for manual control, to detect whether the actuator is in good working condition, when we are running the engine idle motor for action test, you can control the size of its opening, with the idle motor in different degrees of opening, the engine idle speed should produce corresponding high and low changes, Through the above action test, we can confirm that the idle motor itself and its control line are in normal condition. Similarly, we can control the fuel pump relay while the engine is running, and when the fuel pump relay is disconnected, the engine should quickly shut down.
Of course, different decoders can support the action test function is not necessarily the same, some support more action test function, some may be less, but no matter which kind of decoder, we should try to use its function to have doubts about the operation of the actuator for action test, in order to determine whether it belongs to the normal working state.
function:
Because in the data flow function of the decoder, many and actuator signals are voltages. Frequency or other and digital form, in the actual operation of the engine, because the signal changes quickly, it is difficult for us to find the problem from these changing numbers, so we can use the decoder's own oscilloscope function to the crankshaft sensor signal in the electronically controlled engine system. Camshaft sensor signal, lambda sensor signal. Some models of air flow meter signals, injector signals, idle motor control signals. A series of signals, such as ignition control signals, are intuitively provided for our reference in the form of graphical waveforms. When we compare the measured signal waveform with the standard signal waveform, if there is any abnormality, it means that there is a problem with the control circuit or electronic components of the signal itself, and further detailed examination is required. However, if the use of oscilloscopes to check electronic signals also puts forward higher requirements for maintenance technicians to maintain theoretical knowledge of automobile maintenance, maintenance technicians need to be more familiar with the work and control principles of the sensor or actuator under test, and have certain operating skills for the oscilloscope, and can correctly observe the waveform (peaks, amplitudes, etc.), otherwise it is difficult to make good use of this function.
<h1 class="pgc-h-arrow-right" data-track="10" > the difference between a numeric matrix and a decoder</h1>
The price of the digital matrix is much cheaper than the decoder, and the price of the matrix is certainly much higher than that of the decoder in terms of unit price; the specific differences are as follows
The input of the digital matrix is to obtain the stream of the streaming media, which belongs to the one-time extraction, and the decoder is to take the code stream separately from the storage and forwarding; so in the case of the number of roads that need to be displayed, the latter has a considerable bandwidth requirement, because it is necessary to take the code stream three times;
The output of the digital matrix is 4-6 screens, 8 screens belong to the theoretical equipment, the stability is general, the output port is VGA//interface, each screen can display 1.4.9.16 and other screens, and can also assist the splicing processor to complete the effect of the whole screen stitching, the decoder is mostly BNC output, a small part is BNC/VGA/HDMI optional output, generally a decoder corresponds to a display device, Each screen can display 1.4 screens, and the decoder of individual homes can connect multiple screens, 1.4 screens per screen, but the cost of this decoder is 7-12 times the price of ordinary decoders;
In terms of display effect, the resolution of the high-definition decoder can also achieve 1080P output, which is flat with the digital matrix; if the stitching of the number of small roads, the digital matrix can be completed with a built-in stitching card itself, and the decoder is decoded after the HDMI matrix to complete, and the effect difference is not large.
There is no absolute fit and unsuitability; simply put, the decoder is more suitable for the number of decoding channels, decoding effect requirements are not high projects, the best project does not even require storage, or storage time is arbitrary, especially the number of small roads; the digital matrix is suitable for some medium and large projects, the higher the project requirements, the more obvious the matrix advantage; aside from the price factor, there are some projects that ordinary decoders cannot do: for example, the number of high-definition video channels required to be displayed on each screen is more, up to 9 or even 16 channels Or when the front-end brand is not a single manufacturer's video streaming in, the ordinary decoder can not complete the system architecture... Of course, special is OK, but why not recommend... Because I am doing a digital matrix, it is still recommended that you use a digital matrix; in addition, from the practical point of view, the multi-manufacturer function of the digital matrix makes it easier for you to control the standard, which is very suitable for the grasp of some projects, and is not controlled by the front-end brand