HP 8920A - Decoder Frequency Measurements; Field Descriptions for Decoder Modes; The Decoder’s Signal Source

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S:\HP892XX\USRGUIDE\manual\decoscrn.fb
Chapter 8, Signaling Decoder Screen
Field Descriptions for Decoder Modes
Field Descriptions for Decoder Modes
The Signaling Decoder analyzes different data-encoded signaling formats. The
format is selected in the
Mode field in any of the decoder’s screens.
A list of standards for each format is displayed by selecting the
Standard field in
any screen.
Separate screen and field descriptions are given for each screen. The descriptions
are listed in the following order:
• AMPS-TACS/NAMPS-NTACS
• CDCSS (Continuous Digital Controlled Squelch System)
• Digital Paging
• DTMF (Dual-Tone Multi-Frequency) Sequence
• EDACS (Enhanced Digital Access Communications System)
• Function Generator
• LTR (Logic Trunked Radio: Registered Trademark of EF Johnson Company)
•MPT 1327
• NMT (Nordic Mobile Telephone) encoder and decoder
• Tone Sequence
The Decoder’s Signal Source
The decoder always gets its signal immediately after the de-emphasis network of
the AF Analyzer. De-emphasis can be turned on or off on the AF ANALYZER
screen, or can be controlled while using the decoder by assigning a global USER
key to the
De-Emphasis field. Refer to the AF ANALYZER screen’s field
descriptions and functional block diagram in
chapter 5, "AF Analyzer Screen," on
page 99
.
Decoder Frequency Measurements
The decoder uses a different timebase for frequency counting than the AF
Analyzer. Therefore, their measurements may be different when measuring the
same signal (by a very small amount).