Frequency modulation (and fsk) – VXI 3002 User Manual
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Frequency modulation (and FSK)
These commands enable you to select frequency modulation either as a single modulation or as the
sum of two signals, to set the deviation rate, to switch the modulation on and off and to perform DC
FM nulling. (For the latter, ensure that a ground reference is connected to the EXT MOD INPUT
socket before you implement the command.) You can set the modulation oscillator frequency and
select between sine, triangle and square waveforms. Also the phase difference of modulation
oscillator channel 2 relative to channel 1 can be offset in degrees. Both deviation rate and
modulation oscillator frequency can have their step sizes set and then be stepped up or down. And
after having adjusted the deviation rate or the modulation oscillator frequency you can either return
to the reference (rate or frequency) or make the current value the new reference.
FM or FM1 or FM2
Set FM Deviation (short form)
:DEVN
Set FM Deviation
:INC
Set FM step size
Data type : Decimal Numeric Program Data
Allowed suffices : Any one of: GHZ, MHZ, KHZ or HZ
Default suffix : HZ
:<src>
Select modulation source where <src> is any one of: INT, EXTAC,
EXTALC, or EXTDC
:ON
Turn FM ON (locally)
:OFF
Turn FM OFF (locally)
:UP
Go UP one step
:DN
Go DOWN one step
:RETN
Return to original setting
:XFER
Transfer current value to be the new setting
Data type : None
Allowed suffices : None
Default suffix : None
Examples: FM:DEVN 25KHZ;INT;ON
FM1:DEVN 15KHZ;INC 1KHZ;EXTDC
:MODF
Set FM modulation oscillator frequency (short form)
:VALUE
Set FM modulation oscillator frequency
:INC
Set FM modulation oscillator frequency step size
Data type :
Allowed suffices :
Default suffix :
Decimal Numeric Program Data
Any one of: GHZ, MHZ, KHZ or HZ
HZ
:UP
Go UP one step
:DN
Go DOWN one step
:RETN
Return to original setting
:XFER
Transfer current value to be the new setting
:SIN
Select sinusoidal waveform
:TRI
Select triangle waveform
:SQR
Select square waveform
Data type : None
Allowed suffices : None
Default suffix : None