线性调制技术

为了让有限的频谱范围能够容纳更多的通信信道，人们提出了一些线性调制技术，如：QAM（quadratureamplitudemodulation）、QPSK（quadraturephaseshiftkeying）等。

In order to make the limited spectrum range accommodate more communication channels , some linear modulation techniques are proposed , such as QAM ( Quadrature Amplitude Modulation ), QPSK ( Quadrature Phase Shift Keying ), etc.

由于这些线性调制技术具有非恒定包络的特点，当调制信号通过射频功率放大器后将产生互调信号失真，而这种互调产物无法用滤波去除。

Modulated signals with varying envelop will generate intermodulation distortion which can not be eliminated by filter when those signal pass the RF power amplifiers .

高的数据传输率和频谱资源的利用效率是缓解这一问题的有效途径，因此高效率的线性调制技术也应运而生。

Higher data transfer rate and high utilizing rate of the radio frequency resource are the most effective way to solve this problem , which lead to great change in modulation technique .

先进的16-QAM线性无线调制传输技术在BOX系统中的应用

Application of 16-QAM in BOX system

介绍了一种比GMSK具有更优的频谱特性、频谱利用率及更强抗衰落性能的线性窄带调制解调技术（π／4QPSK），并给出了它的DSP实现和相应的性能。

This paper presents a kind of linear narrowband modulation & demodulation technology , named π / 4QPSK (π / 4 shifted QPSK ), which possesses features of better spectrum specification , spectrum utilization ratio and stronger anti fading performance over GMSK etc. DSP based implementation and performance is presented .

该传感器利用半导体激光器的可调制特性和线性调制外差干涉技术，实现了对光缆人为干涉信号的检测。

By the nature of modulated Laser diode and the technology of linear modulated heterodyne intervene , the sensor realized the function of detecting intervene singles .