RIGOL  Chapter 2 Command System 
2-12  DG800 Programming Guide 
frequency coupling mode and frequency deviation/ratio after the frequency coupling function is 
enabled. 
  When the frequency coupling function is disabled, if the current frequency coupling mode is frequency 
deviation, sending this command can set the frequency deviation; if the current frequency coupling 
mode is frequency ratio, sending this command can set the frequency coupling mode to frequency 
deviation and set the frequency deviation. 
  You can also send the 
[:SOURce[<n>]]:FREQuency:COUPle:OFFSet command to set and query the 
frequency deviation in the frequency coupling. 
 
Return Format 
The query returns the frequency deviation in scientific notation. The returned value contains 7 effective 
digits, for example, 1.000000E+02 (the frequency deviation is 100 Hz). 
 
Example 
:COUP1:FREQ:DEV 100      /*Set the frequency deviation in the frequency coupling of CH1 to 100 Hz.*/ 
:COUP1:FREQ:DEV?      /*Queries the frequency deviation in the frequency coupling of CH1 and the 
query returns 1.000000E+02.*/ 
 
 
:COUPling[<n>]:FREQuency:MODE 
 
Syntax 
:COUPling[<n>]:FREQuency:MODE {OFFSet|RATio} 
:COUPling[<n>]:FREQuency:MODE? 
 
Description   
Sets the frequency coupling mode to frequency deviation (OFFSet) or frequency ratio (RATio). 
Queries the selected frequency coupling mode of the specified channel. 
 
Parameter 
 
Remarks 
  When [<n>] is omitted, the commands set and query the related parameters of CH1 by default. 
  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 
(
:COUPling[<n>]:FREQuency:DEViation) or frequency ratio (:COUPling[<n>]:FREQuency:RATio) 
before enabling the frequency coupling function (
:COUPling[<n>]:FREQuency[:STATe]). You cannot 
set the frequency coupling mode and frequency deviation/ratio after the frequency coupling function is 
enabled. 
  You can also send the 
[:SOURce[<n>]]:FREQuency:COUPle:MODE command to set and query the 
frequency coupling mode of the specified channel. 
 
Return Format 
The query returns OFFS or RAT.