4-14 PHASE MODULATION
(FM) CALIBRATION This procedure provides the steps necessary to perform phase modula-
tion (FM) calibration for 682XXB/683XXBs with Option 6. This con-
sists of calibrating the FM VariableGain Control DAC and the FM
Flatness DAC for input sensitivities in Narrow and WideFM modes.
Equipment
Setup Connect the equipment, shown in Figure 4-15, as
follows:
1. Interface the PC to the 682XXB/683XXB by per-
forming the initial setup procedure, pages 4-7 to
4-12.
2. Connect the 682XXB/683XXB rear panel 10 MHz
REF OUT to the Spectrum Analyzer External
Reference Input.
3. Connect the Function Generator Output to the
BNC tee. Connect one leg of the tee to the
682XXB/683XXB front panel FM IN (FM IN). Con-
nect the other leg of the tee to the DMM input.

682XXB/683XXB MM 4-51

PHASE MODULATION
CALIBRATION (FM) CALIBRATION
Serial
I/O

682XXB / 683XXB

COM1
or
COM2

IBM-Compatible PC

Function

Generator

10 MHz
REF OUT
EXT REF
INPUT
RF
IN

Spectrum

Analyzer

OUTPUT
FM IN
(
Φ
M IN) RF
OUTPUT

BNC

Tee

INPUT

DMM

Figure 4-15. Equipment Setup for M Calibration