Freedom R8100 SERIES, Operator'S Manual

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2.2.7.8.1 DPMR transmitter tests
The entire suite of dPMR transmitter tests are available in R8100 Monitor mode after the dPMR soft key
is pressed – see
Figure 2.2.7.8-2 . During radio transmission the R8100 continuously measures the quality
of the transmitted 4FSK signal. Numerical results are displayed as Symbol Deviation and Modulation
Fidelity in the dPMR zone. When the Eye Diagram is selected in the Display Zone, the R8100 overlays
the modulation response during two symbol periods over four “target” crossing points for an ideal dPMR
signal. BER tests require use of the manufacturer’s RSS to place the radio in a special test mode.
2.2.7.8.1.1 RF Zone
Input Level (RF Zone display)
Input Lvl displays the average power in the dPMR channel under test.
Note: When the RF input power on the RF In/Out port is above +20 dBm (100 mW), the R8100 utilizes a
broadband power detector for the measurement. The “Input Lvl” field in the RF Zone changes to “Watt
Meter” to indicate this measurement mode. For best accuracy disable the Pre-amplifier in Monitor Mode,
and set the Gen Port in Generate Mode to RF In/Out.
Freq Error (RF Zone display)
Freq Error displays the frequency difference of the received dPMR transmission carrier minus the R8100
Monitor Frequency.
Deviation (RF Zone display)
Displays the positive peak FM frequency deviation of the received modulated carrier (i.e. from the
Frequency Error mean). See negative peak frequency deviation with Display Zone Bar Graphs.
2.2.7.8.1.2 DPMR Zone
Symbol Deviation (DPMR Zone display)
dPMR radios broadcast voice and data using a 4 level frequency deviation of the carrier to represent
symbols containing data bits as shown in the table below. The nominal symbol deviation value for a
dPMR radio using 4FSK modulation is 1050 Hz in a 6.25kHz channel. Since the deviation of a dPMR
4FSK signal is data dependent, that aspect is factored when measuring overall carrier deviation. The
Symbol Deviation field provides the deviation measurement at symbol decision times.
Bits Symbol Deviation
01 +3 +1050 Hz
00 +1 +350 Hz
10 -1 -350 Hz
11 -3 -1050 Hz
Table 2.2.7.8.1.2-1. dPMR Symbols
Modulation Fidelity (DPMR Zone display)
Modulation Fidelity (FSK error) represents how accurate a transmitter reproduces an ideal theoretical
modulation waveform. The measurement is performed by first removing frequency error and symbol
deviation gain error from the received signal then computing the RMS difference between the deviation