Section 3: Software Reference
S530 Parametric Test Systems Frequency Analysis Option Manual
3-8
S530-923-01 Rev. A / January 2014
freq_setup
Purpose
: This command sets the start, stop, and step (scan resolution or
res_bandwidth
)
frequencies of a scan. The recommended relationship of
res_bandwidth
for different
spans of a scan is listed in the next table.
Format
:
int freq_setup(double min_freq, double max_freq, double res_bandwidth);
Parameters
:
min_freq
Start frequency of the scan in Hz
max_freq
Stop frequency of the scan in Hz
res_bandwidth
Step size (scan resolution in Hz): can only be 1e6, 3e5,
1e5, 3e4, 1e4, 3e3, or 1000
Relation of res_bandwidth and span
Frequency span
RBW
60 MHz
≤
Span
1 MHz
20 MHz
≤
Span
≤
60 MHz
300 KHz
6 MHz
≤
Span
≤
20 MHz
100 KHz
2 MHz
≤
Span
≤
6 MHz
30 KHz
300 KHz
≤
Span
≤
2 MHz
10 KHz
100 KHz
≤
Span
≤
300 KHz 3000 Hz
50 KHz
≤
Span
≤
100 KHz 1000 Hz
Returns
: This command returns a 1, if executed without error; otherwise, a negative number is
returned to indicate an error. The scope card must be initialized before using the
freq_setup
command.
Example
:
double freq;
double ampltd;
.
.
.
Status1 = freq_init( );
Status2 = freq_setup(20e6, 850e6, 1e6);
Status3 = freq_measure(&freq, &ltd);