— 37 —
From the previous menu select:
Pre-Emphasis
to bring up the se-
lection screen:
Turn
the jog wheel to position the brackets around the desired
characteristic:
50us
or
75us
, and then
push
the knob to
set it and fix this selection in the DAVID IV non-volatile
memory. The
None
option is included for test purposes only.
Mono Mode and
Pilot Injection
Press the
Back
button to return to the
Stereo Generator
menu.
Turn
the jog wheel to select
Pilot
and
push
the knob to bring up
the
Pilot
menu:
Here the DAVID IV can be placed in the
Mono
(monaural
transmission) mode for testing or for special circumstances,
though
Stereo
will be the usual choice for normal operation.
Selecting
Mono
removes both the 19kHz stereo pilot tone and
the S’ (L–R ‘stereo difference’) subcarrier.
The 19kHz RDS sync output remains active, however, assuring
that RDS messaging remains an available option in mono.
The factory-default setting of 9.0% stereo pilot injection is
normal for all FM transmissions, although the value may be set
anywhere between 6% and 12%. To reset the level to a non-
standard figure,
turn
the jog wheel to place the brackets around
the
Pilot Level
slider,
push
the knob, and then
turn
it to adjust
the injection level.
Adjusting
the Multiplex
Outputs
Press the
Back
button to return to the
Stereo Generator
menu.
Turn
the jog wheel to select
Multiplex Out
and
push
the knob to
bring up the
Multiplex Output
menu:
The levels of the two independent composite/MPX outputs are
individually adjustable. The open-circuit peak-to-peak voltage
at the rear-panel BNC connectors is displayed below the slider
window. This voltage level, which represents 100% program-
peak carrier modulation, is adjustable between 0.8V p-p and 8V
p-p (+11dBu.)
Turn
the jog wheel to bracket the appropriate
slider (
MPX Level 1
or
MPX Level 2
),
push
the knob to select it, and
then
turn
the knob to dial-in the desired output level.
Summary of Contents for David IV
Page 1: ...DAVID IV FM Audio Broadcast Processor Installation User Guide www inovonicsbroadcast com ...
Page 2: ......
Page 4: ......
Page 66: ... 62 NOTES AND DOODLES ...