Instrument Function
R&S
®
SMU200A
415Operating Manual 1007.9845.32 ─ 15
The crest factor represents the ratio of the peak voltage value to the rms voltage value.
The higher the crest factor and resulting dynamics of a signal, the greater the requirement
for a power amplifier fed by the signal to be linear.
The following modes are available:
"Off"
There is no automatic setting for minimizing or maximizing the crest fac-
tor. The "Phase" setting as defined in the carrier table is in use.
"Minimize"
The crest factor is minimized by internally calculating optimized carrier
phases. The Phase setting displayed in the carrier table is invalid.
"Maximize"
The crest factor is maximized by internally calculating optimized carrier
phases. The Phase setting displayed in the carrier table is invalid.
SCPI command:
[:SOURce<hw>]:BB:ARB:MCARrier:CFACtor:MODE on page 601
Clipping
Switches baseband clipping on and off.
Clipping reduces the peak power of the resulting multi carrier signal according to the input
parameter "Target Crest Factor".
The resulting clipped peak power is defined by sum of the the RMS level of the unclipped
multi carrier signal and the input parameter "Target Crest Factor". Note that clipping
reduces also the RMS level. Hence the resulting crest factor of the clipped signal is slightly
above the "Target Crest Factor". In order to get the unclipped parts of the clipped multi-
carrier signal matched with the unclipped multicarrier signal, the RF output power should
be reduced by the difference between resulting crest factor and "Target Crest Factor".
SCPI command:
[:SOURce<hw>]:BB:ARB:MCARrier:CLIPping[:STATe] on page 602
Target Crest Factor
Sets the value of the desired crest factor, if baseband clipping is enabled.
A "Target Crest Factor" above the crest factor of the unclipped multicarrier signal has no
effect.
SCPI command:
[:SOURce<hw>]:BB:ARB:MCARrier:CLIPping:CFACtor on page 601
Filter Cut Off Frequency
Sets the cut off frequency of the final lowpass filter, if baseband clipping is enabled.
When the cut off frequency is set as half of the output sample rate, a final lowpass filter
improves the spectrum of the clipped multicarrier signal, but may also increase the result-
ing crest factor.
SCPI command:
[:SOURce<hw>]:BB:ARB:MCARrier:CLIPping:CUToff on page 602
Signal Period Mode
Selects the mode for calculating the resulting signal period of the multi carrier waveform.
The carrier table provides an information button to obtain sample rate and file length data
of each carrier.
Baseband Signal - Baseband Block
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