ElectroCraft EPS-HAV1004R, Руководство пользователя

Страница: 15 / 34

13
¾ Bandwidth
There are three possible options provided for selecting bandwidth: 6M, 7M, and 8M. When the
display shows them, user just need swift LEFT and RIGHT key to choose and repressing
ENTER to confirm.
¾ Constellation
Four different constellations QPSK, 16QAM and 64QAM will be shown on the LCD window.
User can set constellation type with the same method mentioned above.
¾ FFT
When user enters FFT (Transmission Mode), the LCD would show the current working
mode. User can move LEFT/RIGHT keys to select and press ENTER key to confirm. 2K
and 8K are the options:
2K: When the device works as current mode, the number of current carrier is 2048
8K: When the device works as current mode, the number of current carrier is 8192
¾ Guard Interval
In communications, guard intervals are used to ensure that distant transmissions do not interfere
with each other. These transmissions may belong to different users (as in TDMA) or same user
(as in OFDM). The purpose of the guard interval is to introduce immunity to propagation delays,
echoes and reflections, to which digital data is normally very sensitive. There are four possible
Bandwidth
6M 7M 8M
Constellation
QPSK 16QAM 64QAM
Transmission Mode
2K 8K
3.1.9 ASI Output