Description; Frequency; Fhss (Frequency Hopping Spread Spectrum) - Panasonic KX-TG2480BXS Service Manual

9 DESCRIPTION

9.1.

Frequency

The frequency range of 2400MHz~2481MHz is used. Transmitting and receiving channel between base unit and handset is same
frequency. Refer to the Frequency Table.
9.2.

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
cordless 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 4 slots from the base unit to the cordless handset, and 4 slots from the cordless handset to the
base unit, total 8 slots in 10ms. By this slot system, simultaneous air link and communication between 4 cordless handsets 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 and per band.
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KX-TG2480BXS / KX-TGA248BXS