4. Regarding high braided cables, generally refer to ca […]
4. Regarding high braided cables, generally refer to cables above 96-128 braid. The obvious characteristics of high-stranded cables are: the shielding layer has low DC resistance, and the low-frequency attenuation below 200khz is reduced, which is beneficial to suppress low-frequency interference. The actual measurement shows that at 200khz-6mhz frequency, due to the "skin effect", the attenuation of 128-strand and 64-strand is the same. (The high-frequency current only flows on the outer surface of the core wire and the inner surface of the shielding layer). From the perspective of frequency distortion (high and low frequency attenuation difference), high braided cables are on the contrary serious. The direct influence is the normal proportional distortion of the various frequency components of the video signal, which directly affects the image distortion;
5. Copper-clad steel core wire: This is a kind of sywv cable, used for the radio frequency transmission above 46mhz of CATV. Due to the "skin effect", the current only flows in the copper skin outside the steel wire, with attenuation characteristics and pure copper core The cable is the same, but the tensile strength is much higher than that of copper wire; but this kind of cable is not suitable for video transmission, and the low frequency attenuation of 0-200khz is too large;
6. The sywv cable video radio frequency transmission characteristics are excellent, and because of the support of the huge cable TV market, the output is large and the price is also advantageous;
7. Regarding the issue of video cables and RF cables, there are misunderstandings and misleadings. The fierce debate in the forum is an example. But everyone should respect the practice: use a 1000m 75-5 cable to transmit a color camera signal, send the end to the monitor, and output the monitor loop to the oscilloscope to measure the amplitude of the "burst head". The original signal is 0.3v , For comparison, the longer the cable, the greater the difference between the two and the easier it is to compare.
The similarities and differences between video cable and RF cable