HP 8920A - Num of Bits; Polarity; RECC Data (NAMPS-NTACS: RECC)

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S:\HP892XX\USRGUIDE\manual\decoscrn.fb
Chapter 8, Signaling Decoder Screen
AMPS-TACS, NAMPS-NTACS Decoder
Measure
(NAMPS-NTACS: RVC)
This field selects the type of decoded data to display: DSAT or DST codes,
Message data, or DTMF (Dual-Tone Multi-Frequency) tone data.
Num of Bits
This field lists the total number of bits displayed. This number is dependent on
Data Rate of the signal being decoded, the
Gate Time of the decoder, and the
size of the decoder’s data buffer.
Operating Considerations
The buffer has a maximum capacity of:
• 1584 bits for decoding Reverse Voice Channel (RVC) data streams.
• 1583 bits for decoding Reverse Control Channel (RECC) data streams.
This measurement is not available for NAMPS-NTACS RVC decoding.
See Also
Gate Time
field description, on page 273
Polarity
This setting is used to match the polarity of the encoded signal being analyzed.
Normal Operation. When this field is set to
Norm, a logical high (1) is displayed
when a positive peak in the received signal is detected. A negative peak displays a
logical low (0).
Inverted Operation. When this field is set to
Invert, a logical high (1) is
displayed when a negative peak in the received signal is detected. A positive peak
displays a logical low (0).
RECC Data (NAMPS-NTACS: RECC)
This display field lists the decoded data serially as it is received. This is the same
information that the AMPS-TACS
Data (hex) measurement displays.