ModOut On/Off FM

Function Group

Menu Map

Description

(MOD)

4

This softkey (Option 002 only) lets you output the internally- generated frequency modulation waveforms to the rear panel AM/FM OUTPUT connector. When scaled exponentially at 10 dB/V, the maximum output voltage is offset to 0 V and the minimum voltage level is -4 V.

Programming Codes

See Also

SCPI:

MODulation:OUTput:SOURce FM MODulation:OUTput:STATe ONlOFFlllO

Analyzer: NONE

m, also see “FM” and “Modulation”.

Modulation

General Circuit Theory The synthesizer’s amplitude and pulse modulation performance is directly tied to the ALC (Automatic Level Control) system. Refer to the ALC block diagram in Figure M-l. The ALC system controls the amplitude or power level of the RF output. A portion of the output signal is detected, summed with the reference level signal, and the difference (error) signal drives an integrate-and-hold circuit. The integrator output drives the RF output power level via the linear modulator. When the sum of the detected and reference signals is

0 volts, the output of the integrator is held at a constant level and the RF output is leveled. This loop is bandwidth-limited by the integrator and the integrate-and-hold circuit. Notice, however, that there is a feedforward path that allows changes in power level that are bandwidth-independent from the rest of the ALC loop. Power level information supplied by the level DAC and AM input travels the feedforward path to drive a linear modulator. (See (ALC) for additional information on the ALC system.)

M-12 Operating and Programming Reference

HP 8360

 

User’s Handbook