56
GEX-P900DAB
3) Guard interval
The time 25% more than the sampling time required for processing DAB signals by FFT is called "guard interval." For
multipath within the time of guard interval, errors can be corrected in most cases, regardless of the D/U ratio.
Mode 1
2048 points (1 ms):
Number of samples required for FFT
512 points (250 µs):
Guard interval
The time of guard interval depends on modes. Different time of guide interval is used for transmitting frequency,
receiving speed (vehicle speed), etc.
S1
S2
S1
S2
Actual DAB signal
Interference between
different symbols
(effect of delay)
Time required for FFT
(1 ms)
Guard interval (250 µs)
Received DAB signal
S1
S2
Time required for FFT for every symbol
Delayed multipath wave
Direct wave
(OFDM wave)
Содержание CRT2193
Страница 4: ...4 GEX P900DAB 2 2 EXTERIOR ...
Страница 8: ...8 GEX P900DAB DIGITAL SECTION A 3 3 A 1 2 3 4 B C D 1 2 3 4 A a A b A a 1 3 ...
Страница 9: ...9 GEX P900DAB SYSTEM CONTROL RF SECTION A 2 3 5 6 7 8 A B C D 5 6 7 8 A a A b A a 1 3 ...
Страница 10: ...10 GEX P900DAB SELECTOR ISOLATOR MUTE POWER SUPPLY ASENSE BSENSE A 1 2 3 4 B C D 1 2 3 4 A a A b A b 1 3 ...
Страница 11: ...11 GEX P900DAB POWER SUPPLY ASENSE BSENSE POWER SUPPLY CEK1033 1 4mH 5 6 7 8 A B C D 5 6 7 8 A a A b A b 1 3 ...
Страница 14: ...14 GEX P900DAB BAND3 RF AMP L BAND RF AMP ANT DUMP POWER SUPPLY PLL A 1 2 3 4 B C D 1 2 3 4 A a A b A a 2 3 ...
Страница 15: ...15 GEX P900DAB L BAND DOWN CONVERTOR 5 6 7 8 A B C D 5 6 7 8 A a A b A a 2 3 ...
Страница 16: ...16 GEX P900DAB 2nd MIXER 1st MIXER PLL SL SAW FILTER NULL DETECTOR A 1 2 3 4 B C D 1 2 3 4 A a A b A b 2 3 ...
Страница 17: ...17 GEX P900DAB DIGITAL SECTION A 3 3 A 1 3 5 6 7 8 A B C D 5 6 7 8 A a A b A b 2 3 ...
Страница 20: ...20 GEX P900DAB DAB DECODER RF SECTION A 2 3 A 1 2 3 4 B C D 1 2 3 4 A a A b A a 3 3 ...
Страница 23: ...23 GEX P900DAB SELECTOR DAC OPT IN OUT A 1 3 5 6 7 8 A B C D 5 6 7 8 A a A b A b 3 3 ...
Страница 24: ...A MAIN UNIT 24 GEX P900DAB A 1 2 3 4 B C D 1 2 3 4 4 PCB CONNECTION DIAGRAM 4 1 MAIN UNIT A ...
Страница 26: ...26 GEX P900DAB A 1 2 3 4 B C D 1 2 3 4 A MAIN UNIT A ...
Страница 27: ...27 GEX P900DAB 5 6 7 8 A B C D 5 6 7 8 SIDE B A ...
Страница 42: ...42 GEX P900DAB AK4321VFP TC74HC126AF TC74HCT541AF ...
Страница 59: ...59 GEX P900DAB 7 3 2 BLOCK DIAGRAM A ...