4.2 Verify Pilot Level; Pilot Phase Adjustment - Solidyne AUDIMAX 362 Manual De Uso

4.2 Verify Pilot Level

a) Connect to ground the test point TP1 in
order to eliminate the 19 KHz pilot tone.
Use a good DC-20
oscilloscope at the MPX output connector.
Connect a sine wave generator at the LEFT
input of the audio processor, at 1 Khz, + 4
dBm output. Verify
waveform looks like FIG-1. Set the output
level preset to maximum (4 Vpp).
b) Replace the audio
processors Left input for audio program
(music or voice). Please carefully take note
of this peak to peak value; let name it Xpp.
c) Disconnect the audio program from the
LEFT input and disconnect the ground of the
test point TP1. Then, the 19 Khz pilot tone
will appear.
d) With the oscilloscope measure the peak to
peak value of the 19 Khz pilot tone; let
name it Ppp.
The percentage level of pilot tone will be:
Pilot Level [%] = 100.Ppp / Xpp
e) This value must be between 9 to 11 %
Otherwise, please contact our factory.
NOTE: If you have a Solidyne VA16 modulation
monitor or BELAR FMS-2 measurement set, you will be
able to measure pilot
transmission.
Pág. 16
Mhz calibrated
that the output
generator at the
tone level from on-air
AudiMax 362
4.3

Pilot Phase adjustment

This method is an absolute system not dependent
from the calibration of the Modulation Monitor.
You will need a very
oscilloscope (Tektronix preferred) with vertical
10x undistorted span. Proceed:
a) Change the PHASE jumper (JF1) from the
Normal "N" position to calibrate "C" position.
b) Input a sine wave generator at 1 KHz, +4 dBm,
at Left Channel of the audio processor. Adjust
the level of wave generator to get 4 Vpp MPX
output.
c) Connect the oscilloscope to the MPX output in
mode DC.
Use the sine wave output of audio generator,
to synchronize the oscilloscope sweep. Adjust
the sweep to 5 uS/Div. Modify with trigger
level, the center of the wave in order to have it
centered at screen.
Adjust vertical sensitivity to 50 mV/Div. You
must get a signal like FIG-2.
If not, you must do a slight change in the
frequency knob of the audio generator in order
to avoid integral multiplication factors that do
not allow you to appreciate the correct image.
FIG.2 Pilot Phase 10X
Calibrate the P10 Phase Control to get zero
phase error. The phase error is indicated by
the tilt of the imaginary line between H1-H2
points. When this line is full horizontal, the
phase is correct.
e) Change the phase calibration jumper to
NORMAL mode ( "N" position).
good DC-20 Mhz
SOLIDYNE