HP 8920A, User Manual

Page: 389 / 658

389
Chapter 10, Signaling Encoder (AF Generator 2)
Using the EDACS Encoder
Testing EDACS Mobiles
When the mobile is turned on, it automatically tunes to its pre-programmed
control channel frequency. The Test Set generates the control channel’s carrier
and site identification data using the RF Generator’s and the EDACS Encoder’s
settings. (The RF carrier level for the control channel and working channel is
adjusted using the
Amplitude
field on the DUPLEX TEST screen.) Once the
mobile is receiving the Control Channel, the encoder can send a digital message to
the mobile to go to a designated Working Channel for making receiver tests (this
is called a handshake).
Testing the Mobile’s Receiver
If the working channel’s RF carrier’s level is high enough, the mobile’s receiver
unsquelches to allow the modulating signal (speech or a test tone) to be heard
from your mobile’s speaker.
If the audio output (speaker) connection of your mobile is connected to the
AUDIO IN connectors of the Test Set, you can then make receiver audio-quality
measurements such as distortion at 1 kHz, and SINAD.
Testing the Mobile’s Transmitter
The EDACS Encoder’s information is used to help the EDACS Decoder receive
and decode transmitted data from the mobile. After entering all of the information
in the EDACS Encoder screen, the EDACS Decoder screen is accessed to get the
mobile transmitting and to decode the digital data. With the transmitter keyed, you
can access the TX TEST or DUPLEX TEST screen to measure transmitter power,
and transmitter frequency or transmitter frequency error. You can also decode and
display the transmitted data using the EDACS Decoder. Refer to the
"EDACS
Decoder" on page 295
for more information on EDACS Transmitter Testing.