Spectrum analysis
R&S
®
RTP
413User Manual 1337.9952.02 ─ 12
Span/RBW Ratio
Defines the coupling ratio for Span/RBW. This setting is only available if CALCulate:
MATH<m>:FFT:BANDwidth[:RESolution]:AUTO is ON.
Remote command:
CALCulate:MATH<m>:FFT:BANDwidth[:RESolution]:RATio on page 1446
Resolution BW
Defines the resolution bandwidth. Note that the resolution bandwidth is correlated with
the span, record length and acquisition time. If a constant record length is to be used,
the RBW may be adapted if the required number of samples cannot be acquired. If
span and RBW values are coupled, changing the span will also change the RBW.
For details see Chapter 9.1.1, "Fundamentals of FFT analysis", on page 402.
Remote command:
CALCulate:MATH<m>:FFT:BANDwidth[:RESolution][:VALue] on page 1446
CALCulate:MATH<m>:FFT:BANDwidth[:RESolution]:ADJusted? on page 1445
Window type
Windowing helps minimize the discontinuities at the end of the measured signal inter-
val and thus reduces the effect of spectral leakage, increasing the frequency resolu-
tion.
Various different window functions are provided in the R&S RTP to suit different input
signals. Each of the window functions has specific characteristics, including some
advantages and some trade-offs. Consider these characteristics carefully, to find the
optimum solution for the measurement task.
Window type Frequency
resolution
Magnitude
resolution
Measurement recommendation
Rectangular Best Worst Separation of two tones with almost equal amplitudes
and a small frequency distance
Hamming
Hann
Good Poor Frequency response measurements, sine waves, peri-
odic signals and narrow-band noise
Blackman Harris
(default)
Worst Best Mainly for signals with single frequencies to detect har-
monics
Accurate single-tone measurements
Gaussian Good Good Weak signals and short duration
Flattop2 Poor Best Accurate single-tone measurements
Kaiser Bessel Poor Good Separation of two tones with differing amplitudes and a
small frequency distance
Remote command:
CALCulate:MATH<m>:FFT:WINDow:TYPE on page 1446
Use color table
If enabled, the spectrum waveform (and a spectrogram, if available) is displayed
according to the assigned color table. For information on the available color tables, see
Chapter 4.3.2, "Color tables", on page 98.
FFT analysis
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