Fm Modulation - HP 8360 B Series User Manual

FM Modulation

frequency list mode, step sweep mode, search leveling mode, sweep
frequency mode, AM or pulse modulation, among others. (For a
complete explanation of the selection sequence, see "Getting Started,
Advanced" .)
Frequency modulation can be accepted from an external source at
the FM connector or can be internally generated by swept signal
generators with Option 002. The damage level of the FM input is
All FM Driver board allows you to change the input impedance to
600 R. (See "Adjustments" in the
Generator/HP 8360 L-Series Swept CW Generator Service Guide.)
The FM sensitivity can be scaled to either 100 kHz/V, 1 MHz/V, or
10 MHz/V.
When internal FM is chosen (Option 002), the rate and deviation
are set by softkeys in the FM menu. The waveform menu provides
a choice of sine, square, triangle, ramp, or noise waveforms. The
monitor menu lets you output the internally generated modulation
waveforms to the rear panel AM/FM OUTPUT connector. The
scale of the FM output depends on the FM deviation chosen. The
following table shows the scale versus deviation. The monitor menu
also lets you display the value of the FM deviation.
FM Coupling
Whether provided from an external source or generated internally
(Option 002), the FM system can be either AC or DC coupled. If
you choose AC coupled FM, you will be modulating a phase-locked
carrier. This is the specified synthesized operation. The modulation
rate must be 100 kHz or greater. If not, the frequency changes
caused by the modulation are inside the phase-lock loop bandwidth
and the output will not be linear FM. For modulation frequencies
below 100 kHz, choose DC coupled FM. In this mode, the phase
locked loop is de-activated. This means that the swept signal
generator is operating as an open loop sweeper. The swept signal
generator will not be phase locked, and therefore, be aware that the
phase noise and CW frequency accuracy specifications do not apply.
HP 8360 B-Series Swept Signal
Operating and Programming Reference M-17
FM Modulation