3 WLAN Mode
3.9 Spectral Flatness Measurement
–
Exponential: After the average count is reached, each successive data
acquisition is exponentially weighted and combined with the existing average.
–
Repeat: After reaching the average count, the averaging is reset and a new
average is started.
Remote
Command
[:SENSe]:FLATness:AVERage:TCONtrol EXPonential | REPeat
[:SENSe]:FLATness:AVERage:TCONtrol?
Example
:FLAT:AVER:TCON REP
:FLAT:AVER:TCON?
Preset EXPonential
State Saved Saved in instrument state.
Range Exponential|Repeat
Search Length
Enables you to specify the Search Length for WLAN spectral flatness measurement.
Please note, this parameter determines the length of data to be acquired. In order to
assure channel estimation, preamble should be included in, therefore Search
Length should not be less than summation of long preamble, short preamble and
payload, or actual data.
Remote Command
[:SENSe]:FLATness:SLENgth <time>
[:SENSe]:FLATness:SLENgth?
Example
:FLAT:SLEN 1ms
:FLAT:SLEN?
Preset 700.00 us
State Saved Saved in instrument state.
Min/Max For Option B25 (BW 25 MHz):
28.0 us / 88.89 ms
For OptionB40 or Wider (BW 40 MHz or wider):
28.0 us/(4.0e6/Info BW/1.25)
Symbol Timing Adjustment
Normally, when demodulating of an OFDM symbol, the guard interval is skipped
over, and an FFT is performed on the last portion of the symbol time. However, this
means that the FFT would include the transition region between this symbol and the
following symbol. To avoid this, it is generally beneficial to back up away from the
end of the symbol time, and use a part of the guard interval.
WLAN Mode User's &Programmer's Reference 1490
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