Freedom R8100 SERIES, Operator'S Manual

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2.2.7.3 PROJECT 25 Test Mode (Conventional)
The optional R8100 PROJECT 25 (P25) Test Mode allows testing of conventional (non-trunked) APCO
Project 25 phase 1 (P25) compliant mobile stations (radios) and base stations (repeaters) in simplex and
duplex modes. P25 radios use a digital transmission format employing Continuous 4 level FM (C4FM)
modulation. P25 repeaters may also transmit LSM (Linear Simulcast Modulation) and WCQPSK (wide
Continuous Quadrature Phase Shift Keying) modulation schemes which are compatible with C4FM
receivers. The R8100 PROJECT 25 mode provides a grouping of test functions compliant with the
TIA/EIA-102.CAAA measurement standard. These include symbol deviation, modulation fidelity, Bit
Error Rate (BER) test patterns, Frequency Error, and Power. A means is provided to change the Network
Access Code (NAC) and edit the P25 Voice Frame to adapt to the system under test. In addition there is
an Eye Diagram with graphical representation of the P25 signal, and a Voice Loopback function that
enables the Voice Loop feature (U.S. patent 5703479) for audio verification of the radio’s end-to-end
operation.
The manufacturer’s Radio Service Software (RSS) is required to perform some tests in P25 mode because
certain measurements (BER) require placing the radio in a special test mode. Tests that don’t require RSS
include power, Frequency Error, Modulation Fidelity, Symbol Deviation, and Symbol Rate Error.
Averaging can be applied to some measurements by the System Settings. The Eye Diagram, Constellation
Plot, Distribution Plot and Voice Loopback also provide qualitative indication of the radio’s performance.
Figure 3.2.8.4-1 shows the R8100 main screen after choosing the PROJECT 25 Test Mode in Monitor
mode.