Modulation is the process of loading low-frequency signals onto high-frequency carriers. ( )

Both AM and NBFM have same transmission bandwidth, they are linear modulation schemes.

Separation may also be referred to as ________. A: caution B: protection C: modulation D: modification

The process of pulse coding modulation can be simply divided into two processes: sampling and coding.

_______ is the name of the process of converting from analog to digital. A: Modulation B: Optical recognition C: Demodulation D: Virtualization

The simple high frequency sinusoidal wave which contains no information of its own is（ ） A: modulation B: general function C: carrier D: transmission

对光载波的调制按照是否干预光源驱动电流可以分为 The modulation of optical carrier can be divided according to whether or not to interfere with the driving current of light source

The analog and digital modulation types include ( ). A: PM, FSK, ASK, PSK, Sine B: Square, AM, FM, PM C: FSK, ASK, PSK, DC D: AM, FM, PM, FSK, ASK, PSK, DSB-AM

脉冲宽度调制（Pluse Width Modulation，简称为PWM）技术，就是把恒定的直流电源电压调制成频率一定、宽度可变的脉冲电压序列，从而可以改变平均输出平均电压的大小。

乐曲在进行中变换调性称为转调（modulation），转调是重要的作曲手法之一。转调的方法和类型很多，从调关系来说，有近关系转调和远关系转调。（）