Rigol DG822 - Page 85

Chapter 2 Command System RIGOL
DG800 Programming Guide 2-71
Parameter
Name
Type
Range
Default
[<n>]
Discrete
1|2
1
<frequency> Real
Frequency range of the current
waveform of the specified channel
900 Hz
Remarks
 You can set the sweep boundaries via the center frequency and frequency span
(
[:SOURce[<n>]]:FREQuency:SPAN). Different sweep waveforms correspond to different center
frequency and frequency span ranges. Besides, the center frequency and frequency span are mutually
affected. Define the minimum frequency of the currently selected waveform
min
F
, the maximum
frequency as
max
F
and
2/)(
maxmin
FFF
m
+=
. The range of the center frequency (defined as
center
F
)
is from
min
F
to
max
F
. The range of the frequency span (defined as
span
F
) is affected by the center
frequency. When the center frequency is smaller than
m
F
, the range of the frequency span is
)(2
min
FF
center
−×±
; when the center frequency is greater than
m
F
, the range of the frequency span is
)(2
max center
FF −×±
.
 When [:SOURce[<n>]] or [<n>] is omitted, the system sets the related parameters of CH1 by default.

The start frequency, stop frequency, center frequency and frequency span fulfills the following
equations.
|)(|
stopstartcenter
FFF +=
;
|)(|
startstopspan
FFF −=
Wherein,
center
F
——center frequency;
span
F
——frequency span;
start
F
——start frequency;
stop
F
——stop frequency.
 The generator will restart to sweep from the specified "start frequency" after the "frequency span" is
modified. In large-scale sweep, the amplitude characteristic of the output signal might change.
Return Format
The query returns the frequency span in scientific notation, with 7 effective digits. For example,
8.000000E+02 (the frequency span is 800 Hz).
Example
:SOUR1:FREQ:SPAN 800 /*Sets the frequency span of the sweep function of CH1 to 800 Hz.*/
:SOUR1:FREQ:SPAN? /*Queries the frequency span of the sweep function of CH1 and the query
returns 8.000000E+02.*/
[:SOURce[<n>]]:FREQuency:STARt
Syntax
[:SOURce[<n>]]:FREQuency:STARt {<frequency>|MINimum|MAXimum}
[:SOURce[<n>]]:FREQuency:STARt? [MINimum|MAXimum]
Description
Sets the start frequency of the sweep function of the specified channel.
Queries the start frequency of the sweep function of the specified channel.
Parameter
Name
Type
Range
Default
[<n>]
Discrete
1|2
1
<frequency> Real
Frequency range of the current
waveform of the specified channel
100 Hz