GW Instek AFG-2000 User Manual - Manual (Page 119)

REMOTE INTERFACE
117
Return Parameter <NR3> Returns the frequency in Hz.
Query Example SOUR1:FM:INT:FREQ? MAX
>+2.0000E+04
Returns the maximum frequency allowed.
SOURce[1]:FM:DEViation
Set
Query
Description Sets or queries the peak frequency deviation of the
modulating waveform from the carrier waveform.
The default peak deviation is 100Hz.
The frequency deviation of external sources is
controlled using the ±5V MOD INPUT terminal on
the rear panel. A positive signal (>0~+5V) will
increase the deviation (up to the set frequency
deviation), whilst a negative voltage will reduce
the deviation.
Note
The relationship of peak deviation to modulating
frequency and carrier frequency is shown below.
Peak deviation = modulating frequency – carrier
frequency.
The carrier frequency must be greater than or
equal to the peak deviation frequency. The sum of
the deviation and carrier frequency must not
exceed the maximum frequency for a specific
carrier shape + 1kHz. If an out of range deviation
is set for any of the above conditions, the deviation
will be automatically adjusted to the maximum
value allowed and an ―out of range‖ error will be
generated.
For square wave carrier waveforms, the deviation
may cause the duty cycle frequency boundary to
be exceeded. In these conditions the duty cycle will
be adjusted to the maximum allowed and a ―-221‖
error will be generated.