Monitoring Signal Characteristics
R&S
®
SMW200A
564User Manual 1175.6632.02 ─ 16
Figure 8-5: CCDF diagram of a 5MHz LTE Signal with enabled reference curve (green) (Level -30 dBm,
PEP -18.43 dBm)
X-axis = level over the average signal power, where the average power (RMS) corresponds to the
origin
Y-axis = probability of exceeding the average power, that is the percentage of time the signal spends
at or above the power level specified by the X-axis
1 (marker 2) = the point where the trace crosses the x-axis; indicates the highest peak that is found in the
sample block = 11.47 dB higher than average.
2a (marker 1) = interpolation: 10% of the samples exceed 3.5 dB above average
2b = interpolation: 1% of the samples exceed 6.5 dB above average
The CCDF diagram on Figure 8-5 is calculated over 8 KSamples and corresponds to a
signal with the following characteristics:
●
"Baseband > LTE" and "Test Model > E_TM 1.1 5 MHz"
●
"Status bar > Level = - 30 dBm" and "Status bar > PEP = - 18.43 dBm"
A level of -30 dBm and a PEP of -19.4 dBm result in a peak to average ratio of
11.57 dB.
The PEP value does not indicate how often the peak level is reached. The CCDF
shows the probability for reaching a dedicated instantaneous power.
Signal acquisition points: See Table 8-2.
Power Spectrum
The power spectrum displays the signal spectrum which is calculated from the I/Q sig-
nal with fast Fourier transformation (FFT). The power density over frequency is dis-
played.
Displaying Baseband Signal Characteristics in Real-Time
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