TB 9-6625-2076-24
(14) Set DDM to .046 and press FUNCTION/CONTROL T/F U/L D/R pushbutton.
(15) Repeat (10) through (13) except to calculate ratio divide value recorded in (10)
above by value recorded in (11) above.
b. Adjustments
(1) Alternately press TONE SELECT 90 Hz and 150 Hz pushbuttons (only one
TONE SELECT pushbutton on at a time) and adjust R7 (fig. 1b) until voltage between the
two tones is within 50 V (R).
(2) Press TONE SELECT 150 Hz pushbutton (all other TONE SELECT
pushbuttons off). Adjust R4 (fig. 1b) for a 1 V rms indication on multimeter (R).
(3) Press TONE SELECT 90 Hz pushbutton. If multimeter does not indicate 1 V
rms, repeat (1) and (2) above until correct indications are obtained.
(4) Adjust R5 (fig. 1b) for a 1.500 V rms indication on multimeter (R).
16. Glideslope DDM
a. Performance Check
(1) Connect multimeter to TI COMP output (rear panel).
(2) Press FUNCTION/CONTROL STD pushbutton and enter a frequency of
335.00 MHz into TI.
(3) Press TONE SELECT 90 Hz pushbutton (all other TONE SELECT
pushbuttons off). Record multimeter indication.
(4) Press TONE SELECT 150 Hz pushbutton (all other TONE SELECT
pushbuttons off). Record multimeter indication.
(5) Divide the measured value of one tone by the other to determine the voltage
ratio. Calculated ratio will be between 0.99975 and 1.00025.
(6) Connect multimeter to TI DEMOD output (rear panel).
(7) Repeat (3) through (5) above. Calculated ratio will be between 0.99745 and 1.00255.
(8) Connect equipment as shown in figure 3. Set decade resistor to 47 k .
(9) Press TONE SELECT 90 Hz pushbutton (all other TONE SELECT
pushbuttons off) and enter the first DDM setting in table 10. Record multimeter indication.
NOTE
Proper DDM steps can be entered by pressing
FUNCTION/CONTROL STEP RDL DDM pushbutton.
(10) Press TONE SELECT 150 Hz pushbutton (all other TONE SELECT
pushbuttons off). Record multimeter indication
(11) Divide value recorded in (10) above by the value recorded in (9) above.
Calculated ratio will be within limits specified in Table 10.
(12) Repeat technique of (9) through (11) above for the remaining DDM settings
listed in table 10. Calculated ratio will be within limits specified.
