Bnc 645 User Manual download pdf (Page 154)

154

PM:INTernal:FUNCtion

{SINusoid|SQUare|RAMP|NRAMP|TRIangle|NOISe|USER}

Specify the shape of the modulating waveform. This applies only when the

modulation source is Internal (PM:SOUR INT). Noise can be a modulating

waveform, but cannot be used as a carrier waveform, neither do Pulse nor dc.

The default modulating waveform is a sine waveform.

-- Square waveform has 50% duty cycle.

--Ramp waveform has 100% symmetry

--Triangle waveform has 50% symmetry.

--Negative Ramp waveform has 0% symmetry.

--If an Arbitrary(USER) waveform is chosen to be the modulating waveform, it is

automatically limited to 4k points. Extra points are removed using decimation.

PM:INTernal:FUNCtion?

Query the modulating function used in phase modulation. “SIN”, “SQU”, “RAMP”,

“NRAM”, “TRI”, “NOIS” or ”USER” string indicating the modulating function will

be returned.

PM:INTernal:FREQuency {<frequency>|MINimum|MAXimum}

Specify the modulating waveform frequency. This applies only the modulation

source is internal (PM:SOUR INT). The range is from 2 mHz to 20 kHz and the

default is 10 Hz.

PM:INTernal:FREQuency? [MINimum|MAXimum]

Query the internal modulating frequency in Phase modulation. The internal

modulating frequency in hertz will be returned.

PM:DEViation {<peak deviation in hertz>|MINimum|MAXimum}

Specify the phase deviation in degrees. Phase deviation represents the peak

variation in phase of the modulated waveform from the carrier waveform. The

range is from 0 to 360 degrees and the default is 180 degrees. When an external

source is selected, the carrier is modulated with an external waveform. The

phase deviation is controlled by the ±5v signal on the rear panel Modulation In

connector. It means that when you choose to have a deviation of 180 degrees,

then a +5V signal level corresponds to a 180 degree phase shift. Lower the

external signal level is, less the deviation is.

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Bnc 645 User Manual Page 154