The difference between car DVR and ordinary DVR
Vehicle hard disk video recorder belongs to the market segment of traditional embedded hard disk video recorder. It is an emerging special product developed with the application of digital video and audio coding technology in vehicles.
The car hard disk video recorder combines advanced technologies such as digital video and audio codec, hard environment large-capacity data hard disk storage, automotive electronics, wireless video network transmission, gps satellite positioning, etc., to realize video and audio monitoring in the passenger operation industry, special vehicle industry and other related fields.
Car hard disk video recorder is not a new product of the times in the security industry, but when it comes to technical content, I am afraid that only those who have actually done car hard disk video recorders can appreciate it. What is the difference between car DVR and ordinary DVR?
Ordinary hard disk video recorders use 220v alternating current, and the stability of voltage and current is relatively stable. Furthermore, the location environment of ordinary hard disk video recorders is fixed, and the relative vibration opportunities are scarce, so the anti-vibration function of ordinary hard disk video recorders can be ignored. But car DVRs are different. First of all, the voltage and current on the car cannot be understood according to the conventional ideas. The voltage on the car is 12 / 24v, but in fact, the 12v car cannot do 12v voltage regulation, and the same is true for the 24v. Therefore, the design of the power board It is important to design the power board with many aspects in mind. How to design the power supply of car DVR? In order to ensure the normal operation of the car DVR, the output power of the power supply board must first be stable. In a fixed narrow voltage environment, because the input voltage and current are basically stable, and in terms of electricity, the output power determines the input power.
Therefore, only one adapter is required for the power of the ordinary hard disk video recorder. An adapter is nothing more than a transformer. A filtering circuit is a bit conscientious and a protection circuit is added. Unconscientious protection circuits are not installed. It is cheap, so the cost of ordinary hard disk recorders and maintenance costs are relatively low. But for a car hard disk video recorder, the first thing to do is narrow and refine the dynamic voltage and current. How to ensure the normal operation of the car DVR, stable voltage and current are important, but on the other hand, the input power of the device is fixed. From w = u * i, we know that when the voltage changes, the current also changes, and the voltage follows The direction of current change is always the opposite. So if the starting voltage is made lower, the relative starting current will increase. It is so simple on the macro level, but it can take a lot of work to achieve this function stably and ensure the normal operation of the device. The first is the design of the protection circuit. You must know that the power supply board of the car hard disk video recorder needs within 1 hour. After hundreds of shocks, the protection circuit does not work well. In some cases, the power supply board is damaged. In other cases, the power supply board is directly damaged.