Instrument Function
R&S
®
SMBV100A
383
Operating Manual 1176.8016.02 ─ 17
The I/Q data and marker data are located in separate memory areas of the SDRAM
and can be independently configured whereas each marker signal requires one bit of
the available memory size. In some cases, it might be useful to generate a modulation
signal without additional marker signals in order to increase the maximum waveform
length.
The example below explains the dependency between the number of enabled marker
signals, the available memory size and the resulting waveform length.
Example: Calculating the maximum waveform length
The calculation in this example is based on an instrument equipped with option
R&S
SMBV-B10 (32 MSamples).
●
Total Memory Size = 128 MB
●
Required Memory Size (per complex sample) = 32 bits + 2 bits = 34 bits = 4.5
bytes, where:
–
the raw I/Q samples are stored as 16 bit values, i.e.
for I/Q data = 2 x 16 bits = 32 bits (16 bits per I/Q channel)
–
each software defined marker requires 1 bit, i.e.
for 4 enabled markers = 2 x 1 bit = 2 bits
●
Maximum Waveform Length (with 2 markers) = 128 MB / 4.2 bytes = 30 MSamples
●
Theoretical Maximum Waveform Length (no markers) = 128 MB / 4 bytes = 32
MSamples
Hence, a memory size of 128 MB yields a maximum waveform length of 30
MSamples
if two markers are enabled. The maximum waveform length increases to 32
MSamples
if the internal hardware markers are used, and the complete memory is available for
I/Q data.
In instruments equipped with additional options, e.g. R&S
SMBV-B10/
B51+R&S
SMBV-K511 and R&S
SMBV-K512, the maximum available memory increa-
ses up to 1
GSamples.
The minimum length of a waveform is 512 samples. A waveform is shorter than this
value is automatically repeated until it reaches the minimum length.
Specifying Delay and Inhibit Values in Time Units
In the R&S
SMBV you can delay and suppress trigger events.
The delay and inhibit values are usually expressed in the units of the generated signal.
To enable you to define the exact delay or inhibit period directly as a time value (e.g. in
seconds), the instruments provide additional parameters. You can determine the units
the values are defined in and the instrument calculates and displays the actual time
delay/inhibit.
Baseband Signal - Baseband Block
