蓝牙AVG Freq Dev 指标指教
The Modulation is GFSK (Gaussian Frequency Shift Keying) with a BT=0.5.
The Modulation index must be between 0.28 and 0.35. A binary one is repre-
sented by a positive frequency deviation, and a binary zero is represented by a
negative frequency deviation. The symbol timing shall be better than +/-20 ppm
For each transmit channel, the minimum frequency deviation (Fmin = the
lesser of {Fmin+, Fmin-}) which corresponds to 1010 sequence shall be no
smaller than +/-80% of the frequency deviation (fd) which corresponds to a
00001111 sequence.
In addition, the minimum deviation shall never be smaller than 115 kHz. The
data transmitted has a symbol rate of 1 Ms/s.
The zero crossing error is the time difference between the ideal symbol period
and the measured crossing time. This shall be less than +/- 1/8 of a symbol
period.
So minimum deviation is 1MHz * 0.28 / 2 =140KHz
So maximum deviation is 1MHz * 0.35 / 2 =175KHz
thanks,
really insight.....
连接及发射情况同上；loopback 模式，Hopping off.①使用DH5，包长度12500µs；payload 11110000…；tester的测量带宽至少1.3MHz，通带纹波±550kHz；发射频点2402；tester计算每“00001111”8bit的平均频率偏移，为了得到每一位的正确的偏移量，至少采样4次，取4次的平均值。对于8bits中每2、3、6、7的偏移被记做△f1max，所有的△f1max的平均值为f1avg；重复至少10个包②使用DH5，包长度12500µs；payload 10101010…；tester计算每“01010101”8bit的频率偏移， 8bits中偏移最大值记做△f2max，所有△f2max的平均值为f2avg；重复至少10个包测试
①140kHz≤△f1avg≤175kHz.
②至少99.9％的最大频率偏移△f2max≥115kHz
③△f1avg/△f2max≥0.8
find the chinese for you ,wish useful
呵呵
正解！