Analog Devices ADRV9029 User Manual page 81

Preliminary Technical
Data
Compare the statistics from a TM2 signal from 1 with a fully filled TM3.1 NR100 signal in Figure 78 which has an rms value of -
12dBFS per frame. A 10us moving average of the TM3.1 NR100 signal results in a mean of -11.99dBFS, and a standard deviation
of 0.12dB, which is close to the frame rms of -12dBFS.
To further illustrate the point of Table 45, the distribution of moving average computed for the waveform under test for avg
duration equal to 10us, 100us and 1000us is shown below. The standard deviation decreases, and convergence towards expected
value increases as the averaging duration increases for the signal under test.
The Cumulative Distribution Function of the waveform for different averaging durations (Figure 80) also provides an insight into
averaging duration that could ensure stability for the signal under test, by engaging different sub-carriers across frequencies in a
CLGC sampling period.
It can be observed that with averaging duration set to 1ms, the CDF of the signal is guaranteed to lie between -37.2dBFS to -
37.1dBFS for 99.83% of the time.
Figure 80. Distribution of moving avg 10us, 100us
Figure 81. Moving average distribution with duration = 1ms
Rev. PrA | Page 81 of 82