Panasonic KX-TC1881B, Service Manual

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10.2.1. TDD Frame Format
The TDD frame is 2mS in length, and is composed of two symmetrical 960 S TX and RX
subframes. Each subframe contains 96 bits of 10 S duration, with 40 S guard times
between both TX and RX subframes.
Each subframe consists of the following four fields:
- A 16-bit Preamble field
- An 8-bit Data Channel field
- An 8-bit Sync Word
- A 64-bit ADPCM Payload
10.3. Spread Spectrum
Transmission and reception are operated using the spread spectrum method.
DSS (Digital Spread Spectrum)
Mixing the original signal with the pseudo random noise code (PN code) works the spread
spectrum. In this system PN code is 15 chip. Although the band width is spread fifteen times,
the power level per channel becomes lower.
Fig. 8
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