Models 682XXB with Firmware Version2.18 and above
Models 683XXB with Firmwave Version2.20 and above
Models 682X5B/683X5B with Firmware Version1.07 and above
This procedure provides the steps necessary to perform FM calibra-
tion. This consists of calibrating the FM Meter circuit and the FM
VariableGain Control DAC. The FM Variable Gain Control DAC is
calibrated for input sensitivities in Locked, Locked Low-Noise, Un-
locked Narrow,and Unlocked Wide FM modes.
Equipment
Setup Connect the equipment, shown in Figure 4-13, 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 Ref-
erence 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. Connect the
other leg of the tee to the DMM input.
4-44 682XXB/683XXB MM
FM
CALIBRATION 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 RF
OUTPUT

BNC

Tee

INPUT

DMM

Figure 4-13. Equipment Setup for FM Calibration