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FFT
R&S
®
RTM20xx
118
User Manual 1317.4726.02 ─ 01
"Hamming"
The Hamming window is bell shaped. Its value is not zero at the borders
of the measuring interval. Thus, the noise level inside the spectrum is
higher than Hanning or Blackman, but smaller than the rectangular
window. The width of the spectral lines is thinner than the other bell-
shaped functions. Use this window to measure amplitudes of a period-
ical signal precisely.
"Blackman"
The Blackman window is bell shaped and has the steepest fall in its
wave shape of all other available functions. Its value is zero at both
borders of the measuring interval. In the Blackman window the ampli-
tudes can be measured very precisely. However, determining the fre-
quency is more difficult. Use this window to measure amplitudes of a
periodical signal precisely.
"Rectangle"
The rectangular window multiplies all points by one. The result is a high
frequency accuracy with thin spectral lines, but also with increased
noise. Use this function preferably with pulse response tests where start
and end values are zero.
Remote command:
Y-Scaling
Defines the scaling unit for the y-axis. The display values are valid for 50
Ω
termination
impendance. To achieve this, the existing internal terminating resistor can be used, or an
external terminating resistor can be connected parallel to the high impedance input.
To set the scale value, use "FFT Setup" > "Y-Scale".
"dBm"
logarithmic scaling; related to 1
mW
"dBV"
logarithmic scaling; related to 1
Veff
"Veff"
linear scaling; displays the RMS value of the voltage
Remote command:
FFT-Setup
Defines the settings for the FFT window. The display can be restricted to the results for
a certain time base extract and to a specified frequency range.
Reference for FFT key