modulation

英语翻译
这个是传输网里的一句话 Generation,coding and modulation of Layer 1
signalling谁帮我翻译下

英语翻译
(called NEZ-Non return to zero)modulation of a 38khz IR carrier frequency.All bits are of equal length of 1ms in this protocol,with half of the bit time filled with a burst of the 38khz carrier and the other half being idle.A logical one is represented by a burst in the first half of the bit time.A logical zero is represented by a burst in the second half of the bit time.The pulse/pause ratio of the 38khz carrier frequency is 1/4,to reduce power consumption.

英语翻译
14.1 IEEE 802.15.4 Modulation Format
This section is meant as an introduction to
the 2.4 GHz direct sequence spread
spectrum (DSSS) RF modulation format
defined in IEEE 802.15.4.For a complete
description,please refer to [1].
The modulation and spreading functions
are illustrated at block level in Figure 37
[1].Each byte is divided into two symbols,
4 bits each.The least significant symbol istransmitted first.For multi-byte fields,the
least significant byte is transmitted first.
Each symbol is mapped to one out of 16
pseudo-random sequences,32 chips
each.The symbol to chip mapping is
shown in Table 42.The chip sequence is
then transmitted at 2 MChips/s,with the
least significant chip (C0) transmitted first
for each symbol.The modulation format is Offset –
Quadrature Phase Shift Keying (O-QPSK)
with half-sine chip shaping.This is
equivalent to MSK modulation.Each chipis shaped as a half-sine,transmitted
alternately in the I and Q channels with
one half chip period offset.This is
illustrated for the zero-symbol in Figure 38.