Agilent Technologies N3970A User Manual

Page 25

■

ALIBRATION

& M

AINTENANCE

Enabling / disabling ‘shift’ keypad & re-booting the
microprocessor: See section on ‘getting started &
turning on.

Calibration

Calibration can be readily performed without opening the
instrument. Calibration is performed by setting up a singlemode
laser source at a stable but non-critical power level between -10
and -30 dBm, and adjusting the meter reading to the same value
as that shown by a reference meter.

A l t e rn a t i v e l y, known calibration constants can be
re-entered directly without using other equipment. This is useful
in case old calibration constants are to be put back, or the
instrument memory has been corrupted.

R e q u i red are laser light sources with accurate, calibrated
wavelengths and good power stability, a power meter with
appropriate calibrated wavelengths, singlemode test leads, an
anti-tamper label, and a 0.1” programming jumper. Check the
calibration certificates on your reference equipment, to ensure
current validity.

To enable calibration mode, open the battery compartment, hold
back the battery spring, remove the anti-tamper label, and insert
a 0.1” pitch programming shunt. Manipulation of the shunt is
easier with needle nose pliers. The meter will display ‘CAL’

Before commencing calibration:

■ Clean all connectors and the meter input ports very carefully

■ Ensure all devices have been at stable room temperature for

over an hour

■ The source is fully warmed up at the

to be calibrated,

■ The meter battery is good.
On the meter to be calibrated, record the existing calibration
offsets as follows:

■ Select POWER METER, +/- to set the wavelength, and

MAX/MIN twice to display the offsets. Note them down.
(you can also re-enter or adjust known offsets at this point)