Freedom R8100 SERIES, Руководство оператора

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2.2.7.9 P25 II Test Mode
The optional R8100 P25 II Test Mode allows testing of APCO Project 25 phase 2 compliant mobile
stations (radios) and base stations (repeaters) in simplex test mode. P25 phase 2 stations use a two-slot
TDMA digital transmission format and modulation schemes compliant with the TIA-102.BBAB
specification. The quaternary baud rate is 6000 symbols per second.
Phase 2 radios employ Harmonized Continuous Phase Modulation (HCPM) with practically constant
amplitude envelope and significant ISI for inbound traffic channels. Phase 2 repeaters employ Harmonized
Differential Quadrature Phase Shift Keyed modulation (HDQPSK) with varying amplitude envelope and
insignificant ISI for outbound traffic channels. The R8100 provides a grouping of test functions for the
asymmetrical superframe structure that are compliant with the TIA-102.CCAA measurement standard.
These include RF slot power, power envelope/timing, symbol rate, symbol deviation, modulation fidelity,
frequency error, frequency deviation, bit error rate (BER), and test pattern generator. In addition there is
an eye diagram, distribution plot, frequency constellation, and power profile with graphical
representations of signals.
The 180-symbol TDMA slots (0 and 1) form a 60 ms frame, 6 frames form a 360 ms superframe, and 4
superframes form a 1.44 second ultraframe. Two logical channels (LCH0 and LCH1) are allocated in the
physical slots (1
st
| 2
nd
) in an asymmetrical superframe for use in all over-the-air communications as
illustrated in the table below. An inbound slot is used only if its logical channel is active; the unused slot
may be called a null slot because it does not contain transmitter power. However, both outbound slots are
transmitted even if neither logical channel is active. Testing of both logical channels is supported by the
R8100.
Frame 1 2 3 4 5 6
Outbound LCHn 0 | 1 0 | 1 0 | 1 0 | 1 0 | 1 1 | 0
Inbound LCHn 1 | 0 1 | 0 1 | 0 1 | 0 1 | 0 0 | 1
Table 2.2.7.8.1.4-1. P25 Phase 2 Logical Channels
The manufacturer’s Radio Service Software (RSS) is required to perform some tests because certain
measurements (e.g. BER, symbol rate) require placing the radio in a special test mode. Although TIA
measurement methods assume that the transceiver is in test mode, most R8100 test functions will work
with a live signal. Averaging can be applied to some measurements by the System Settings. Figure
2.2.7.9.1-1 shows the R8100 main screen after choosing the P25 II Test Mode in Monitor mode.