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ELECTRICAL SYSTEM
Test Item Unit
Frequency range KHZ
87.5-108MHz (FM1
、
FM2
、
FM3)
步长
0.1MHz
Intermediate frequency KHZ 10.7±0.3
Finite noise sensitivity (30dB S/N) dBμV ≤6
Signal impetuous ratio (monophonic) dB ≥55
Static sensitivity dB ≤20
Stereo noise limit sensitivity (S/N=30dB) dB ≤15
Stereo noise limit sensitivity (S/N=50dB) dB ≤26
Stereo Signal to Noise Ratio (A weight)
dB
≥50
Automatic selection station sensitivity dB 24±8 dB 24±8
Double signal selectivity dB ≥70(±400KHZ)
Image reject dB ≥70
Intermediate frequency suppression dB ≥70
Am inhibition dB ≥45
balance dB ≤15
Stereo separation (A weight) dB ≥22
balance dB ≤1
Frequency characteristics (50uS pre-weighted) dB 0---3
-3dB limiting sensitivity dB ≤15
FM performance index
Fault diagnosis
Failure phenomenon failure cause analysis
The key switch turns on and the
screen goes black
◆ Check whether the central control fuse is in good condition
and the circuit is in good condition according to the electrical
schematic diagram
◆ Check whether the central control connector is loose
◆ Check whether the central control power supply voltage is
normal, if less than or equal to 7V or 18V, the screen will be black
The map cannot be loaded
◆ Check the location to see if there is an offl ine map
downloaded in advance
◆ If you do not download the offl ine map, check whether the
central control is connected to WiFi
The map cannot display the
current position of the vehicle in
real time.
◆ Check whether the central control PIN12 and PIN19 have
signals
◆ If there is a signal, replace the TBOX
Radio can not search the radio Check whether the radio antenna interface is loose
When the radio works or the
music works
When, the external speaker or
Bluetooth headset can not listen
To the sound
◆ Check whether the external device is normal
◆ Reconnect the external device with Bluetooth