led flash light,green laser pointer

After green laser pointer is acquired from the warehouse
The bit error rate. The experimental results show that: atmospheric laser communication system is basically able to work properly, but when you run into fog, heavy rain, snow and other inclement weather, the communication quality of the system is decreased, bit error rate increases, reaching 10 ? 3, close to 10 ? 2, however, the use of channel coding techniques, bit error rate after correction basically can reach 10 ? 5. Turbo code and RS (30, 10) error-correcting code system has better error correction performance, improve the effect on system performance, they are error-correcting bit error rate of 10 ? 5 below. General weather conditions in the rain, the average error rate was maintained at 10 ? 4, RS (15) and LDPC codes of atmospheric laser communication system performance improvement, improved bit error rate reached 10 ? 6. The purchase and supply management of green laser pointer  will be presented.
In the case of sunny and cloudy days, the average bit error rate correction before the system has been less than 10 ? 7, the bit error rate after the correction is to reach 10 ? 9. The error correction performance. RS (15) error correction analysis. The measurement results in Table 1 show that: RS (15, 9) code for correcting the system, in the case of good weather as sunny, cloudy, bit error rate correction before the system be maintained at more than 10 ? 7 the bit error rate after correction is less than 10 ? 9, the error correction effect; in the rain, rainy days and light to moderate rain and other weather conditions before the error correction bit error rate was maintained at 10 ? 4, after correction system the bit error rate was maintained at 10 ? 6, the correction effect is better. With the increase of bit error rate, error correction performance. The green laser beam of green laser pointer is brighter.
The weather of heavy rain, the error correction performance is not very obvious, more need correction codeword. From the above analysis: RS (15, 9) code can be used for atmospheric laser communication system in the sunny, cloudy, and the bit error rate smaller applications. Wrong system bit error rate of less than 10 ? 9, in a small case of heavy rain, bit error rate before correction was maintained at 10 ? 4, the BER performance after the correction can reach 10 ? 7, general rain to improve the impact of the atmospheric channel can use the RS (30, 10), results can be improved to eliminate the impact of rain on the atmospheric channel. In heavy rain, heavy rain, fog and snow weather conditions, the bit error rate in 10 ? 2 ? 10 ? 3, the error correction bit error rate is maintained at between 10 ? 5 ? 10 ? 6. When the power of green laser pointer is small.
So that from the measurement results can indicate: RS (30, 10) code can be used as the error rate is high atmospheric laser communication system channel coding. Also showed that the RS (30, 10) code error correction ability is far better than the RS (15, 9) code from the experimental measurement results can be seen, RS (15, 9) code error correcting capability of about RS (30 10) Code 1/6. Sunny and cloudy, LDPC codes as channel coding, correcting the error rate of the system before 10 ? 7, the bit error rate after the correction is less than 10 ? 9, reflects a better error correction system performance; in the fog, heavy rain, heavy snow, the error correction bit error rate maintained at between 10 ? 2 ? 10 ? 3, the error correction system performance in the range of 10 ? 4 ? 10 ? 5 and correct wrong to improve the effect is not obvious, the error correction performance is not very satisfactory.  green laser pointer  are in the suitable quantities.