Satellite DMB(Digital Multimedia Broadcasting) derives from satellite DAB(Digital Audio Broadcasting), but recent development of digital condensation technology widened the multimedia contents covering audio and simple video clips. Satellite DMB is a service receiving diverse multimedia contents through personal portable terminal or automobile terminal utilizing satellites. Satellite DMB has a unique trait of providing moving service distinguished from existing fixed satellite broadcasts.
For the service in shadow area such as urban areas, basement, and building inside, utilizing satellites for moving service is basis, and ground relay instrument called gap filler should be performed.
Types of gap filler include Frequency Conversion Gap Filler, Direct Amplifying Gap Filler, and Spotlight Gap Filler.
Board performing the main function of gap filler system is TCCU(TDM to CDM Converter Unit).
| NO |
Function |
Specifications |
Comments |
| 1 |
RF Input Frequency Range |
1,000 MHz ~ 1,500 MHz |
|
| 2 |
Input Range |
-61dBm ~ -28 dBm |
|
| 3 |
Input Connector Type |
F - Female |
|
| 4 |
Modulation Type |
QPSK |
|
| 5 |
Number of Channel |
32 Chs. (Pilot 1Ch, including spare 1Ch) |
|
| 6 |
Symbol Rate |
18.432 MHz (1/2 Convolutional Encoder) |
|
| 7 |
Error Correction |
RS (204,188) |
|
| 8 |
Interleaver |
12 Cycle Convolution |
|
| 9 |
Error Correction Inside Code |
Convolutional Encoder 1/2 |
|
| 10 |
Roll-OFF Filter |
Roll-Off Factor 0.35 RRC |
|
| 11 |
BER |
210E-4 Max
(After Viterbi-decode Eb/No4.5 dB, 18.432 MHz |
|
| 12 |
Impedance |
75 Ohm(VSWR < 2.5) |
|
| 13 |
LNB Frequency Error |
Provided by Tuner |
|
| 14 |
Storage Temperature |
-40 ~ +75 |
|
| 15 |
Operation Temperature |
-30 ~ +70 |
|
| 16 |
Operation Humidity |
10 % ~ 90 % |
|
| NO |
Function |
Specifications |
Comments |
| 1 |
Walsh Code CH |
32 Chs. (Pilot 1Ch, including spare 1Ch) |
|
| 2 |
Spread Ratio |
64 |
|
| 3 |
Short Code |
Walsh |
|
| 4 |
Long Code |
PN 12, 2048 chip x 2 |
|
| 5 |
Frame Length |
12.75 ms |
|
| 6 |
Roll-OFF Filter |
over sampling
0.22 1:4 Interpolation 18.432 |
|
| 7 |
Filter Window |
Hanning |
|
| 8 |
Modulation Type |
DS-CDMQPSK |
|
| 9 |
Output Terminal |
SMA Type Female |
|
| 10 |
Output Impedance |
50 |
|
| 11 |
Gap Filler ID |
Message |
|
| NO |
Function |
Specifications |
Comments |
| 1 |
VFD Display |
2x16 Characters |
|
| 2 |
Key Menu Control |
5 Keys - Menu, Up, Down, Enter, ESC |
|
| 3 |
Communication Status Display |
Green/Red LED (TX/RX) |
|
| 4 |
Equipment Status Display |
4 Status - Input, Output, LNB DC, PAU |
|
| 5 |
Communication Port |
D_SUB Connector (9pin, Female) |
|
| 6 |
Temperature Sensor |
-40 ~ +125 |
|
| NO |
Function |
Specifications |
Comments |
| 1 |
Communication Status Display |
Green/Red LED (TX/RX) |
|
| 2 |
Equipment Status Display |
3 Status - Input, Output, LNB DC |
|
| 3 |
Communication Port |
D_SUB Connector (9pin, Female) |
|
