Rohde & Schwarz R&S UPP, User Manual

Page: 267 / 938

Instrument Functions
R&S
®
UPP
251 User Manual 1411.1055.32 ─ 10
"Pink" Time domain:
WAV files for generating broadband pink noise that is free of perio-
dicity, for the fixed frequencies between 11.025
kHz and 192 kHz
(and thus for all configurable generator bandwidths) are available in
the "User" directory. They can be played back using the "Play" gener-
ator function and are called
Pink_Noise_xxxxx.WAV
, where
xxxxx
designates the sampling rate in Hz.
Frequency range:
Pink noise. The amplitude of the sine-wave lines between the lower
and upper cutoff frequency is proportional to the function , and thus
is attenuated by 3
dB per octave. Measurements performed using a
third-octave analyzer return a uniform frequency spectrum.
"Third Octave" Frequency domain only:
Pink noise with a bandwidth of one third octave. The center frequency
is adjustable.
"File" Frequency domain only:
The amplitude distribution is read from the file which is displayed in
the next parameter field "Shape File".
Remote command:
SOURce:RANDom:SHAPe
on page 707
Shape File
Frequency domain, only with the selection "Shape File"
File containing the amplitude distribution.
The button opens a browser that you can use to select the file.
"File format: "
ASCII file containing max. 8192 amplitude values which have to be entered as a
sequence of numbers (value range FLOAT). The file must contain one line with the
keyword "FREQUENCY_FILE" before the number sequence. Comment lines must
begin with '#' and can be used anywhere in the file. No distinction is made between
uppercase and lowercase characters. The recommended and preset file extension is
'.FTF'. However, due to the keyword "FREQUENCY_FILE" which must always be
entered, it is also possible to use any other file extension.
Beginning at 0 Hz, the amplitudes of the individual frequency lines must be entered as
dimensionless numerical values. The numbers only indicate the amplitude ratio of the
lines in respect to each other and not the output amplitude. It is set after the phase
optimization according to the value defined in the "Volt Peak" parameter field. Since
the ratio of peak value to RMS value is calculated internally, it is also possible to enter
the RMS value.
The frequency grid is derived from the "Spacing" setting defined in the panel. Alterna-
tively, it can also be defined in the file. To do so, the keyword
frequency_spacing
(not case-sensitive) must be specified, followed by the value in Hz. If this value is less
than the minimum value: (sampling rate/16384), the minimum value is set.
Generator Signals