Surveillance camera generally use the most common means of transmission is baseband video transmission (baseband transmission directly without any processing such as frequency conversion and transmission of television signals the way). The advantages associated with this transmission is a transmission system architecture, within an individual range, low distortion, low noise (SNR);
drawback is that the transmission distance can not be too far, you must transfer the extent needed by the cable characteristics, and root video coaxial cable can only send the tv signal. apexis Shenzhen surveillance Android IP Camera manufacturers into more powerful makers.
This transmission has the advantages of high stability, simple equipment used in the system, to facilitate wiring, which has been widely applied in real life. But the cable the involving high bandwidth and low frequency, resulting in a proof transmission cable, the amplitude and phase difference end up being in the low band and high band, specially in the phase distortion is just too large, it is difficult with a simple circuit to compensate. And low-frequency part of the baseband transmission is very very likely to strong electric launch towers, base stations, motor, inverter and other sources of interference. Such as the common source of interference your past project:
1, radio interference:
When the erection of this cable in the air, IP Camera your cable itself is equivalent to very long antenna. To be a result from the antenna effect, the cable will produce considerable radio interference voltage and interference current while on the cable jacket, the current through the bottom cable at both ends and to constitute a loop, therefore the terminal load will produce radio interference voltage in the signal, interference signal mixed with the video signal. This interference signal on is acceptable manifested as more frequent stripes, Shu Wen, twill, though serious flood the entire video image.
2, high-frequency interference:
The cable shielding shielding effect is worse for that lower frequency signal carrier telephone, radio signals, for this reason, the introduction of high-frequency interference signals. A result from the interference of the horizontal stripes on the majority.
3, power disturbances:
When protection network camera system for you to be IT given it and the finish at equivalent time grounded, the existence of resistance due to both ends of the soil potential differences and the cable jacket between 2 places, inducing the potential difference of 50Hz, resulting in the interference signal voltage. When the interference signal is superimposed on it signal, in a way that the normal image appears on a vast horizontal dark band.
4, the harmonic interference:
Harmonic interference mainly on the large current or hollywood power lines, power cables to the encompassing radiation signal, its frequency 2500Hz and 125000Hz, conflict with the video signal on the low frequency band.
5, the transmission line interference:
Poor quality of video cable shielding performance (layer sparse or non-shielded copper media shield, etc.), the cable resistance is too large, the playback quality signal resulting from the severe attenuation.
6 clean power disturbances:
For example, Network Camera the grid power SCR FM speeder, silicon controlled rectifier device, SCR cross-DC conversion device will power pollution. Clean power for the camera and also other active equipment to job instability, so the formation of disturbance.
The above makes the scene for the video image to selection of of interference by the strong interference, we solve the above can be the good regarding video interference in SHWIT brand. Specific solutions are as follows:
A frequency shift: the frequency shift technology video signals (0-6MHZ) frequency shift quickly 49-300MHZ; video signals through long-distance transmission, the sender of the anti-jamming device at the receiving end to restore the signal into a video signal output. Increased frequency in long-distance transmission at the same time effective to avoid an associated with interfering Wireless IP Camera signals;
Code: video signal into the anti-jamming device, the digital encoding process, the decoding process before it reaches the monitoring center exercise equipment. In order to the involving interference regarding video signal interference and video signals, crosstalk and attenuation;
3 enhancements: the more signal attenuation to the signal transmission distance farther, so we must be at the sending end of the signal carrier capacity to bolster so in which it can transmit farther;
4, adaptive: with automatic adjustment of the signal strength and adaptation functions throughout the device, unit has 0 distance towards most long-distance transmission automatic adaptability;
Free debugging: a device should canrrrt you create an involving debugging part of our equipment at the factory already has a 90% market adaptability, basically you can use to connect, without the extra debugging;
6, security: wide voltage (12V-24V) design concept, prevent a sudden increase or sudden drop of the moment the supply voltage burned out equipment to protect the equipment and apparently of the operator;
7, the monitoring response to stability: some time before the device is manufactured, aging and test trials, and engineering statistics, this product can reach the continuous utilization of all-weather, and able to meet the long-term stability requirements.