Motorola PDR 3500, Базовое руководство по обслуживанию

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9-18 September 27, 2000 68P81093C75-O
Step 5. Use the Volume Up button to increase the volume to
maximum. Measure the audio level using the R2001.
• Audio level should measure approximately 0.75 to
1.5 V p-p. If not, suspect faulty SCM.
Step 6. Change R2001 injection signal to
• VHF: 0.25 µV (-119 dBm)
• UHF: 0.35 µV (-116 dBm).
Step 7. Measure the receiver 12 dB SINAD sensitivity. The
value should read 12 dB, or greater. If not, tune the
preselector (VHF and UHF only) and re-check 12 dB
SINAD. If 12 dB SINAD cannot be achieved, suspect
the following:
• Damaged cable from top panel receive port to
preselector
• Faulty receiver
• Excessive loss in the R2001-to-station RF cable
NOTE: To measure 12 dB SINAD, the station must be
programmed for mixed mode Analog/Digital
operation. Incorrect reading will result if
programmed for Digital Only operation.
NOTE: For VHF and UHF stations only, refer to
5. Preselector Field Tuning Procedure in this
section. Procedures for tuning the receiver
preselector are described.
Step 8. If the station is configured with a duplexer, continue
with Step 9 to test the duplexer’s performance. If the
station is not configured with a duplexer, go to Step
16.
Step 9. Steps 9 through 13 describe a method of measuring
the effect of insertion loss from the duplexer on
receiver sensitivity. Connect the dummy load to the
station’s top panel receive port through a capacitive
coupler (isolated T). Connect the R2001 to the isolated
side of the coupler. (See Figure 8.)