Agilent Technologies FM Peak Frequency Deviation, Agilent E1441A Application Information

FM Waveform Shape The function generator will accept only an internal modulating signal. You cannot modulate with an external source.

Modulating waveform shape (internal source): Sine, Square, Triangle,

Ramp, Noise, or Arbitrary waveform. The default is Sine.

You can use the noise function as the modulating waveform. However, you cannot use the noise function or dc volts as the carrier waveform.

Use the following command to set the modulating waveform shape:

FM:INTernal:FUNCtion SINSQUTRIRAMPNOISUSER

FM Waveform Frequency The function generator will accept only an internal modulating signal. You cannot modulate with an external source.

Modulating frequency: 10 mHz to 10 kHz. The default is 10 Hz.

The sync signal for FM is referenced to the modulating signal (not the carrier). A momentary TTL “high” pulse (> 200 ns) is output at each zero-crossing point of the modulating signal. The signal is output from the front-panel SYNC terminal.

Use the following command to set the modulating waveform frequency:

FM:INTernal:FREQuency <frequency>MINimumMAXimum

FM Peak Frequency Deviation

The peak frequency deviation represents the variation in frequency of the modulating waveform from the carrier frequency.

Peak frequency deviation: 10 mHz to 7.5 MHz. The default is 100 Hz.

The carrier frequency must always be greater than or equal to the peak frequency deviation. If you attempt to set the deviation to a value greater than the carrier frequency (with FM enabled), the function generator will automatically adjust the deviation to equal the present carrier frequency. A -221, “Settings conflict” error is generated and the deviation is adjusted.

The sum of the carrier frequency and peak frequency deviation must be less than or equal to the maximum frequency for the selected function plus 100 kHz (15.1 MHz for sine and square, 200 kHz for triangle and ramp, and 5.1 MHz for arbitrary waveforms). If you attempt to set the deviation to a value that is not valid, the function generator will automatically adjust the deviation to the maximum value allowed with the present carrier frequency. A -221, “Settings conflict” error is generated and the deviation is adjusted.

Use the following command to set the peak frequency deviation:

FM:DEViation <peak deviation in Hz>MINimumMAXimum

32 Agilent E1441A Application Information Chapter 2