Rigol DG822 - Page 81

Chapter 2 Command System RIGOL
DG800 Programming Guide 2-67
 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.
|)(|
stop
startcenter
F
FF
+=
;
|)(|
start
stop
span
FF
F
−=
Wherein,
center
F
——center frequency;
span
F
——frequency span;
start
F
——start frequency;
stop
F
——stop frequency.
 The generator will restart to sweep and output from the specified "Start Frequency" after the "center
frequency" is modified. In large-scale sweep, the amplitude characteristic of the output signal might
change.
Return Format
The query returns the center frequency in scientific notation with 7 effective digits. For example,
5.000000E+02 (the center frequency is 500 Hz).
Example
:SOUR1:FREQ:CENT 500 /*Sets the center frequency of the sweep function of CH1 to 500 Hz.*/
:SOUR1:FREQ:CENT? /*Queries the center frequency of the sweep function of CH1 and the query
returns 5.000000E+02.*/
[:SOURce[<n>]]:FREQuency:COUPle:MODE
Syntax
[:SOURce[<n>]]:FREQuency:COUPle:MODE {OFFSet|RATio}
[:SOURce[<n>]]:FREQuency:COUPle:MODE?
Description
Sets the frequency coupling mode to frequency deviation (OFFSet) or frequency ratio (RATio).
Queries the frequency coupling mode.
Parameter
Name
Type
Range
Default
[<n>]
Discrete
1|2
1
{OFFSet|RATio}
Discrete
OFFSet|RATio
RATio
Remarks
 Frequency deviation mode: the frequencies of CH1 and CH2 have a certain deviation relation. The
parameter relations are F
CH2
=F
CH1
+F
Dev
(the reference source is CH1); F
CH1
=F
CH2
-F
Dev
(the reference
source is CH2). Wherein, F
CH1
is the frequency of CH1, F
CH2
is the frequency of CH2, and F
Dev
is the
frequency deviation.
 Frequency ratio mode: the frequencies of CH1 and CH2 have a certain ratio relation. The parameter
relations are F
CH2
=F
CH1
*F
Ratio
(the reference source is CH1); F
CH1
=F
CH2
/F
Ratio
(the reference source is
CH2). Wherein, F
CH1
is the frequency of CH1, F
CH2
is the frequency of CH2, and F
Ratio
is the set
frequency ratio.
 If the frequency of CH1 or CH2 exceeds the frequency upper limit or lower limit of the channel after the
channel coupling, the instrument will automatically adjust the frequency upper limit or lower limit of
the other channel to avoid parameter over-range.
 Select the desired frequency coupling mode and set the corresponding frequency deviation
(
[:SOURce[<n>]]:FREQuency:COUPle:OFFSet) or frequency ratio
(
[:SOURce[<n>]]:FREQuency:COUPle:RATio) before enabling the frequency coupling function
(
[:SOURce[<n>]]:FREQuency:COUPle[:STATe]). You cannot set the frequency coupling mode and
frequency deviation/ratio after the frequency coupling function is enabled.