IFR NAVAIR NAV-750

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NAVAIR

17—2OAX—737

4.10.6 Verify

that

the

difference

between

the

150

Hz

DEMOD

voltage

recorded

in

step

4.10.3,

and

the

90Hz

DEMOD

voltage

recorded

in step

4.10.5,

is

~2.75 mV rms.

4.11 GIS

CENTERINGTEST

4.11.1

Set

the TI

controls

as

follows:

LOC—G/S switch

to

G/S

LOC

DDM

switch

to

150

Hz

G/S

DDM

switch

to

0

4.11.2

Record

the

150

Hz

DEMOD

voltage

as

indicated

on the

DMM.

4.11.3

Set

the TI

LOC

DDM

switch

to

90

Hz.

4.11.4

Record

the

90

HzDEMOD

voltage

as

indicated

on

the

DMM.

4.11.5 Verify

that

the

difference

between

the

150

Hz

DEMOD

voltage

recorded

in step 4.11.2,

and

the

90Hz

DEMOD

voltage

recorded

in step

4.11.4

is,

2.75

mV rms.

4.11.6

Disconnect

the

DMM

from

theTI.

NOTE

Perform

theappropriate

Spectral

Purity

Tests

subsection

corresponding

to

the

TI

being

calibrated

(4.12

for

NAV—750,

4.13

for

NAV—750A,

and

4.14

for

NAV—750B).

4.12

SPECTRAL

PURITY

TESTS

(NAV-750

ONLY)

4.12.1

Set

the

TI

controls

as

follows:

FREQUENCY

MHz

switches

to

108.000

MASTER

MOD

control

to

UNCAL

[fully

ccw

(0)]

Output

attenuator

control

to

—10

clBm

4.12.2

Connect

the

spectrum

analyzer

input

to

the

TI

RF

output

connector.

4.12.3

Set

the

spectrum

analyzer

for

a

center

frequency

of 108.0 MHz,

and

a

frequencyspan

of

100

MHz/div

with

a

3

MHzresolution

bandwidth.

NOTE

For

the

following

tests, set

thespectrum

analyzer

frequency

span

and

center

frequency

controls

as

necessary

to

check

the

level

ofthe

harmonics

of

the

TI

signals.

20