Anritsu MG369 C Series Programming Manual Download

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Programming with GPIB Commands

2-9 Modulation Commands

MG369xC GPIB PM

PN: 10370-10374 Rev. F

2-23

2-9

Modulation Commands

Table 2-9 on page 2-26

lists the modulation command mnemonic codes. These commands provide for AM, FM,



M, and pulse modulation of the signal generator’s output signal using modulating signals from either the

internal AM, FM,



M, and pulse generators or an external source.

Amplitude Modulation

Two AM modes are available—Linear and Log. In Linear AM mode, sensitivity is variable from
0 %/V to 100 %/V and the amplitude of the RF output changes linearly as the AM input changes. In Log
mode, sensitivity is variable from 0 dB/V to 25 dB/V and the amplitude of the RF output changes exponentially
as the AM input changes.

Internal AM Function

The

AM7

command turns on the internal AM function in Linear mode. The

AM8

command turns on the internal

AM function in Log mode. In Linear mode, the AM depth value is changed using the

ADP1

parameter entry

command. In Log mode, the AM depth value is changed using the

ADP2

parameter entry command. The

modulating waveform is selected using the

AMW(x)

command and the AM rate is set with the

AMR

command.

The

AM0

command turns off the AM function.

Programming Example:

Programming “

AM8 ADP2 20 DB AMW7 AMR 10 KH

” turns on the internal AM function in Log mode, sets the

AM depth to 20 dB, selects a triangle wave as the modulating waveform, and sets the AM rate to 10 kHz.

External AM Function

The

AM1

command turns on the external AM function in Linear mode. The

AM2

command turns on the external

AM function in Log mode. In Linear mode, the external AM sensitivity value is changed using the

AMS

parameter entry command. In Log mode, the external AM sensitivity value is changed using the

ASD

parameter entry command. The

AM0

command turns off the AM function.

Programming Example:

Programming “

AM1 AMS 90 PCV

” turns on the external AM function in Linear mode and sets the external AM

sensitivity to 90 %/V.

Frequency Modulation

Four FM modes are available—Locked, Locked Low-Noise, Unlocked Narrow, and Unlocked Wide.
In the Locked and Locked Low-Noise FM modes, frequency modulation of the output signal is accomplished by
summing the modulating signal into the FM control path of the YIG phase-lock loop. In Locked FM mode, the
maximum FM deviation is the lesser of ±10 MHz or rate



300 for 1 kHz to 8 MHz rates; in Locked Low-Noise

FM mode, the maximum FM deviation is the lesser of ±10 MHz or rate



3 for 50 kHz to 8 MHz rates.

In the Unlocked FM modes, the YIG phase-lock loop is disabled to allow for peak FM deviations of up to
100 MHz. In the Unlocked Narrow FM mode, frequency modulation is obtained by applying the modulating
signal to the fine tuning coil of the YIG-tuned oscillator. Unlocked Narrow FM mode allows maximum
deviations of ±10 MHz for DC to 8 MHz rates.
In the Unlocked Wide FM mode, frequency modulation is accomplished by applying the modulating signal
to the main tuning coil of the YIG-tuned oscillator. Unlocked Wide FM mode allows maximum deviations of
±100 MHz for DC to 100 Hz rates.