蓝牙FCC射频测试总结

yxf_5180

1. 跳频数：
>= 15 channels
根据 FCC PUBLIC NOTICE DA 00-705的要求，如下设置频谱仪：
The EUT must have its hopping function enabled.  Use the following spectrum analyzer settings:   
Span = the frequency band of operation  
RBW ≥ 1% of the span  
VBW ≥ RBW  
Sweep = auto  
Detector function = peak  
Trace = max hold  
Allow the trace to stabilize.  It may prove necessary to break the span up to sections, in order to clearly show all of the hopping frequencies.  The limit is specified in one of the subparagraphs of this Section.  Submit this plot(s).   
2. 跳频间隔
至少25kHz或者2/3 20dB带宽
测试高中低三个频段

The EUT must have its hopping function enabled.  Use the following spectrum analyzer settings:   
Span = wide enough to capture the peaks of two adjacent channels  
Resolution (or IF) Bandwidth (RBW) ≥ 1% of the span  
Video (or Average) Bandwidth (VBW) ≥ RBW  
Sweep = auto  
Detector function = peak  
Trace = max hold  
Allow the trace to stabilize.  Use the marker-delta function to determine the separation between the peaks of the adjacent channels.  The limit is specified in one of the subparagraphs of this Section.  Submit this plot.  
3. 驻留时间
在0.4s * 跳频数 这段时间内，每个channel上占用的平均时间不得大于0.4s；
如DH5模式：
在观察周期内，每个频点跳频数为(1600/6/79) * (0.4*79) hops
Dwell Time = 跳频数 * 单个跳频的占用时间

The EUT must have its hopping function enabled.  Use the following spectrum analyzer settings:   
Span = zero span, centered on a hopping channel  
RBW = 1 MHz VBW ≥ RBW  
Sweep = as necessary to capture the entire dwell time per hopping channel  
Detector function = peak  
Trace = max hold  
If possible, use the marker-delta function to determine the dwell time.  If this value varies with different modes of operation (e.g., data rate, modulation format, etc.), repeat this test for each variation.  The limit is specified in one of the subparagraphs of this Section.  Submit this plot(s). An oscilloscope may be used instead of a spectrum analyzer.
4. 20dB带宽
没有限值，用作其他测试的参考；
测高中低channels

Span = approximately 2 to 3 times the 20 dB bandwidth, centered on a hopping channel  
RBW ≥ 1% of the 20 dB bandwidth  
VBW ≥ RBW  
Sweep = auto  
Detector function = peak  
Trace = max hold   
The EUT should be transmitting at its maximum data rate.  Allow the trace to stabilize.  Use the marker-to-peak function to set the marker to the peak of the emission.  Use the marker-delta function to measure 20 dB down one side of the emission.  Reset the markerdelta function, and move the marker to the other side of the emission, until it is (as close as possible to) even with the reference marker level.  The marker-delta reading at this point is the 20 dB bandwidth of the emission.  If this value varies with different modes of operation (e.g., data rate, modulation format, etc.), repeat this test for each variation.  The limit is specified in one of the subparagraphs of this Section.  Submit this plot(s)
5. Peak Output Power
对于蓝牙，限值为0.125W，即20.97dBm
测高中低channels，并且每一种data rate模式都要测

Use the following spectrum analyzer settings:  
Span = approximately 5 times the 20 dB bandwidth, centered on a hopping channel  
RBW > the 20 dB bandwidth of the emission being measured  
VBW ≥ RBW  
Sweep = auto  
Detector function = peak  
Trace = max hold  
Allow the trace to stabilize.  Use the marker-to-peak function to set the marker to the peak of the emission.  The indicated level is the peak output power (see the NOTE above regarding external attenuation and cable loss).  The limit is specified in one of the subparagraphs of this Section. Submit this plot.  A peak responding power meter may be used instead of a spectrum analyzer.

5. Conducted Band Edge
In any 100 kHz bandwidth outside the frequency band in which the spread spectrum or digitally modulated intentional radiator is operating, the radio frequency power that is produced by the intentional radiator shall be at least 20 dB below that in the 100 kHz bandwidth within the band that contains the highest level of the desired power, based on either an RF conducted or a radiated measurement, provided the transmitter demonstrates compliance with the peak conducted power limits. If the transmitter complies with the conducted power limits based on the use of RMS averaging over a time interval, as permitted under paragraph (b)(3) of this section, the attenuation required under this paragraph shall be 30 dB instead of 20 dB. Attenuation below the general limits specified in §15.209(a) is not required. In addition, radiated emissions which fall in the restricted bands, as defined in §15.205(a), must also comply with the radiated emission limits specified in §15.209(a) (see §15.205(c)).

Span = wide enough to capture the peak level of the emission operating on the channel closest to the bandedge, as well as any modulation products which fall outside of the authorized band of operation  
RBW ≥ 1% of the span  
VBW ≥ RBW  
Sweep = auto  
Detector function = peak  
Trace = max hold  
Allow the trace to stabilize.  Set the marker on the emission at the bandedge, or on the highest modulation product outside of the band, if this level is greater than that at the bandedge.  Enable the marker-delta function, then use the marker-to-peak function to move the marker to the peak of the in-band emission.  The marker-delta value now displayed must comply with the limit specified in this Section.  Submit this plot.  
Now, using the same instrument settings, enable the hopping function of the EUT.  Allow the trace to stabilize.  Follow the same procedure listed above to determine if any spurious emissions caused by the hopping function also comply with the specified limit.  Submit this plot.