Agilent Technologies E8257D PSG, E8267D PSG Using the ALC, Selecting ALC Bandwidth, Yes ARB On

4 Optimizing Performance

In the following sections, this chapter describes procedures that improve the performance of the Agilent PSG signal generator.

•“Using the ALC” on page 119

•“Using External Leveling” on page 120

•“Creating and Applying User Flatness Correction” on page 123

•“Adjusting Reference Oscillator Bandwidth (Option UNR/UNX)” on page 134

Using the ALC

Selecting ALC Bandwidth

For internal leveling, the signal generator uses automatic leveling control (ALC) circuitry prior to the RF output. ALC bandwidth has five selections: automatic, 100 Hz, 1 kHz, 10 kHz, and 100 kHz. In automatic mode (the preset selection), the signal generator automatically selects the ALC bandwidth depending on the configuration and settings (see Figure 4- 1).

Figure 4-1

ALC BW

100 Hz

Yes

Decision Tree for Automatic ALC Bandwidth Selection

	AM OFF			No		No
					AM OFF		AM ON
PULSE OFF					PULSE ON		PULSE ON
			Yes		Yes			Yes
		Yes

No

AM ON

PULSE OFF

Yes

ARB On

No

RF OUTPUT	No	ALC BW	ALC BW	ALC BW
< 2 MHz		1 kHz	10 kHz	100 kHz

To Select an ALC Bandwidth

Press Amplitude > ALC BW > 100 Hz, 1 kHz, 10 kHz, or 100 kHz.

This overrides the signal generator’s automatic ALC bandwidth selection with your specific selection.

For waveforms with varying amplitudes, high crest factors, or both, the recommended ALC loop bandwidth is 100 Hz. Limiting the loop bandwidth of the ALC circuit will prevent the ALC from

Chapter 4 119