Last week，we finish 20 pcs EP2 sample for RF module,
Fistly，we need to test PCBA performance test .include tranamitted power, frequency deviation，and harmonic wave，that took a long time，but not to worry，we can finish it。
Secondly ，we must complete three product test in this week，because customer need to check it and prepare the next mass production，Based on customer needs, in meeting the performance and reliability under the premise of customersto select the most price competitive products is our definition of quality.
Lastly，the distance test must be completed today，and analysis the data，come up with a credible solution to slove the problem about signal attenuation。（Um，that‘s a bit difficult ）
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The record of distance test today as follow。
1 The principle of RF
Firstly, based on a lot of literature an overview of RF technology is presented including fundamental wave signal，carrier signal，modulation and demodulation signals.
The process of retrieving intelligence( data) from a modulated carrier wave; the reverse of modulation.
When receiving, the modem performs the reverse process, and demodulates the data from the carriersignal.
2 Environment disturbance
The communications protocols used by mobile phones often result in low-frequency pulsing of thecarrier signal.
3 Characteristic
The ratio of peak and average power in multi carrier system is much larger than that in single carrier system, and may grow unboundedly as the number of subcarriers grows to infinity.
