HP 8920A - Page 383

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Chapter 10, Signaling Encoder (AF Generator 2)
EDACS Encoder
AFGen2 To
This audio frequency generator control is used to specify where the encoder’s data
is sent:
• FM is used to frequency modulate the RF Generator. This is the normally-used setting.
(Refer to the FM Coupling field description.)
• AM is used to amplitude modulate the RF Generator (not generally used for EDACS sig-
naling).
• Audio Out routes the data to the front-panel AUDIO OUT connector. The signal
could then be used as an external modulation source. (Refer to the Audio Out field
description.)
Operating Considerations
The encoder’s digital signal level is adjusted using the Signaling Dev and
Sub-Audible Dev fields. Changing the AFGen2 To setting automatically alters
the unit-of-measure for both of these fields (kHz, %, or mV).
Audio Out
The audio output coupling field selects ac or dc coupling of the encoder to the
AUDIO OUT connector. Because the EDACS Encoder sends low-speed data, this
field should be set to
DC when the AUDIO OUT port is used. The AFGen2 To
field must be set to
Audio Out to use this function.
Control Channel, Number
This field is used to specify the Control Channel number for the EDACS system
(typically 1 to 25).
Control Channel, RX Frequency
This field is used to specify the Control Channel receive frequency for the mobile.
Control Channel, TX Frequency
This field is used to specify the Control Channel transmit frequency for the
mobile.