7
KX-TG3661JXM/KX-TG3662JXM/KX-TG3668JXM/KX-TG3669JXM/KX-TGA365JXM
4 Technical Descriptions
4.1.
FHSS Description
4.1.1.
Frequency
The frequency range of 2.40 GHz - 2.48 GHz is used. Transmitting and receiving channel between Base Unit and Cordless Handset
is same frequency. Refer to
Frequency Table
(P.49).
4.1.2.
FHSS (Frequency Hopping Spread Spectrum)
This telephone is using an IC chip which has similar specification to WDCT (World Digital Cordless Telephone) and is the
telephone system that can use multiple portable unit simultaneously. The explanation of this system is mentioned below. This
system uses a Time Division Multiple Access/Time Division Duplex (
TDMA
/
TDD
) scheme:
transmitting and receiving frequencies of the Base Unit and Cordless Handset are shared in the same frequency. The
construction of RX/TX frequency data is shown below. It consists of 6 slots from the Base Unit to the Cordless Handset, and 6
slots from the Handset to the Base Unit, total 12 slots in 10ms. By this slot system, simultaneous air link and communication
between 6 Cordless Handset and the Base Unit can be realized. One communication between Cordless Handset and the Base
Unit is done by one slot from the Base Unit to Cordless Handset, and another slot from Cordless Handset to the Base Unit.
DSS makes spectrum spread by multiplying carrier signal by PN code. The purpose to make spectrum spread is to reduce
power density per time and per band. On the other hand,
FHSS
makes spectrum spread by changing channel every 10ms
according to Hopping table. Also the purpose to make spectrum spread is to reduce power density per time andper band.
RX1
RX2
RX4
RX5
RX6
RX3
TX1
TX2
TX3
TX4
TX5
TX6
Base Unit -> Handset
Handset -> Base Unit
10ms
Frequency
5
Frequency
Hopping
FHSS
Frequency
DSS
3
1
4
2
Current
system
Other
system
