Motorola M3097 Service Manual download pdf (Page 18)

©1999 Motorola, Inc.

Cellular OverviewService Manual

7

Analog Cellular Signal Summary (AMPS

and NAMPS)

The diagrams on the following pages out-

line the various uses of the signals employed

in cellular systems. These signals include:

SAT (Supervisory Audio Tone) 5970 Hz, 6000

Hz, or 6030 Hz. Used in AMPS for chan-

nel reuse, muting audio (squelch), and call

continuation [typically ± 2 kHz deviation].

Digital SAT (DSAT) - One of seven codes or

vectors used in NAMPS for the same pur-

pose as SAT [± 700 Hz sub-audible NRZ

data].

Data - Transmitted at 10 kilobits/second in

AMPS and 200 bits/second in NAMPS. Data

is used for sending System Orders and Mo-

bile Identification. Do not confuse data with

the 10 kHz signaling tone. In AMPS, data is

transmitted as Manchester-encoded Fre-

quency Shift Keying (FSK), where the car-

rier is shifted high or low 8 kHz, and the trail-

ing edge transition is used to represent the

logic. In NAMPS, data is transmitted as NRZ

(Non-Return to Zero) FSK, where the carrier

is shifted high or low 700 Hz, and the fre-

quency shift itself is used to represent the

logic.

Signaling Tone (ST) - A 10 kHz tone used in

AMPS for mobile ringing, call terminations,

hand-offs, and switch-hook operation [typi-

cally ± 8 kHz deviation]. ST is always ac-

companied by SAT.

Digital ST (DST) - One of seven digital

equivalents of ST used on NAMPS channels.

The transmitted DST is always the comple-

ment of the assigned DSAT [± 700 Hz sub-

audible NRZ data].

Audio - Includes microphone audio and

DTMF [maximum ± 12 kHz deviation AMPS,

± 5 kHz deviation NAMPS]. DTMF devia-

tion should be measured on the radians scale;

use key five looking for 9 radians. Audio is

accompanied by SAT in AMPS signaling.

AMPS Deviation in kHz

AMPS Voice Channels

Control

Channels

Audio

SAT

± 2

± 4

± 6

± 8

±10

±12

±14

Signal

Tone

DataDataAudio

Data

SAT

SAT

Figure 5. AMPS Deviation in kHz

Analog Cellular

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