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)
Summary of Contents for CRT2193
Page 4: ...4 GEX P900DAB 2 2 EXTERIOR ...
Page 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 ...
Page 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 ...
Page 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 ...
Page 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 ...
Page 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 ...
Page 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 ...
Page 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 ...
Page 26: ...26 GEX P900DAB A 1 2 3 4 B C D 1 2 3 4 A MAIN UNIT A ...
Page 27: ...27 GEX P900DAB 5 6 7 8 A B C D 5 6 7 8 SIDE B A ...
Page 42: ...42 GEX P900DAB AK4321VFP TC74HC126AF TC74HCT541AF ...