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measurement methods to detect and control the design parameters of the transmitter.
This requirement can be met by the CCDF statistic power analysis function of the S2438PA/PB microwave power meter.
In the statistic measurement mode, the instrument doesn't need to trigger an event for measurement, instead, it
continuously samples the signal for measurement. In this section, the statistic power analysis function is briefly
introduced, and then the operation of the statistic analysis function is explained in detail.
3.10.1 CCDF definition
The peak-to-average power ratio of the acquired input signal of the sensor is taken as a discrete random variable Y, and a
probability density function (PDF) of the variable is generated accordingly. The PDF graph can be seen as a power
histogram which represents the percentage of a PRD in the entire power reading sample.
Another means of pulse modulation signal control of a transmitter is a cumulative distribution function (CDF) graph and
a complementary cumulative distribution function (CCDF) graph. CDF represents the percentage of a sampling point in
a specific sample where the power level is less than or equal to a certain value in the entire sample; while CCDF
represents the percentage of a sampling point in a specific sample where the power level is greater than or equal to a
certain value in the entire sample or can be expressed as 1 - CDF (1 minus CDF).
In a CCDF graph, the X-axis
represents the peak-to-average power ratio in dB; the Y-axis represents the probability of occurrence of the
power level greater than or equal to a certain value in dB.
CCDF is mainly designed for signal mixing, power
amplification and signal decoding in the communication system. It can be used to check the effect of modulation mode,
mix signals, evaluate the spread spectrum system and design and manufacture the RF microwave components.
Fig. 3.15Trace Display
Fig. 3.15 shows the trace display of the pulse modulation signal with a period of 100 ms, a pulse width of 50 ms and a
peak power of 16.5 dBm.
