General Dynamics R2600 Series, Operator'S Manual, Page: 316 / 402

Figure 21-13. PROJ 25 CONV Audio Zone - Voice Generate Mode
21-9.1.1 Fixed 1 kHz
The analyzer contains a fixed 1 kHz modulation
source, which can be selected independently from
the other audio synthesizers. Level control and
on-off selection is described above.
21-9.1.2 External
External modulation is applied to the external
modulation input (EXT MOD IN) connector on
the front panel. When external modulation source
is selected, the modulation input is summed with
the microphone input. Level control and on-off
selection for an external modulation source are
selectable via softkey or the TUNING knob.
21-9.2 Voice Frame
The Audio Zone provides for audio source
selection. In generate mode, controls are
provided for both signal level and frequency
deviation settings of the voice baseband signal
that is used to modulate the Project 25 RF
transmissions.
21-9.2.1 Monitor Mode
Voice Frame decode is selectable from the Display
Zone. To display Voice Frame decoded data, refer
to Section 21-10.3. Be sure Monitor is selected in
the RF Control Zone in the upper right section of
display. Move cursor to the Audio Zone and place
the cursor in the “Code:” field. Select Voice
modulation using the
VOICE FRAME softkey.
Selection of Monitor Voice allows for the addition
of the following audio sources:

Ex microphone, or

1 kHz tone
These inputs are selected by using the off and
continuous switches and the level is adjusted using
the keypad or tuning knob. The level range varies
depending on whether the bandwidth (in the RF
Zone) is set to narrow or wide.
BW Setting Audio Level Range
Narrow 0.000 to 0.795 volt maximum,
in 0.001 volt increments
Wide 0.00 to 7.95 volt maximum,
in 0.01 volt increments
21-9.2.2 Generate Mode
The analyzer generates Project 25 voice patterns
when placed in the Generate mode. The Project
25 signal can be clear or encrypted with one of
the hardware algorithms.
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