Section III
Paragraphs 3-14 to 3-17
ground through S-1402C. See figure 3-5. In the
bottom line, the percentage modulation is 14%. This
position the reverse situation takes place.
level can be adjusted with the
Mixed signals from the switching network are fed to
potentiometer. On phase localizer operation, the 9960
the grid of V-1408B, an amplifier common to all
FM signal modulates the r-f carrier at a constant 30%
signals.
modulation regardless of the setting of the LOC-GS
potentiometer.
vialed on the front panel for measuring the unregulated
B+ voltage, the adjusted line voltage, and the carrier
to combine the various signals generated in the proper
level. The meter has a zero to 200 microampere
proportions to provide the functions desired, it is
movement and it is converted to a 0-30 V d-c voltmeter
necessary to mix these signals and switch them to a
by means of multiplier resistor R -1482. A voltage
common output. For the VOR position, 30 cps varia-
divider R-1476-R-1477 provides a 10:1 reduction in
ble phase and 9960 FM are required, The output level
the unregulated B+ voltage so that it can be measured
of the 30 cps variable phase signal is adjusted by
by the 0-30 volt voltmeter. Meter switch S-1403
R-1446 while the 9960 FM output is adjusted with R-
selects the various meter functions. In the CAR
1467. Resistors are connected in series withthe arms
position, the meter is connected to the output of the
of both potentiometers for isolation. For the
demodulator circuit in the r-f section and to R-1480
position, 9960 FM and 30 cps reversible phase are
which is used to zero the meter when no r-f signal is
combined. See figure 3-8. The 30 cps variable phase
signal is disabled by shorting the junction of R -1444
applied to the demodulator.
and R-1445 to ground through S-1402C. In the TONE
LOC position the circuit shown in figure 3-4 exists.
applied to the univerter and is removed from regulator
Connections for the GLIDE SLOPE position are shown
tube V-141O which supplies the 9960 FM circuits in
in figure 3-3. It is necessary to set the NAV-GS
order to lower the load on the dynamotor. The switch
switch to GS to set up the proper glide slope carrier
also operates coaxial relay K-1401 which switches the
frequency. In the 1000
r-f output of V-1506 from the NAV OUTPUT jack to the
oscillator has a 1000 cycle phase shift network switched
univerter input.
in by S-1402D. The 1000 cycle level is controlled by
position provides a signal
useful for calibration since it is the 30 cps variable
cies spaced 100 kc throughout the range 108.0-135.9
phase component of the VOR signal. It is obtained by
mc are generated in the shielded r-f assembly. For
simply omitting the 9960 FM. The 9960 FM position
GS operation, these signals are fed into a univerter
is the other half of the VOR signal and is obtained in a
similar manner. In the 90
which simply adds 200 mc to the input frequency. The
univerter has unity gain throughout the GS band of
disabled by shorting the grid of the 150 cps limiter to
16
