FCC G7C - 实用的电路与原理图

#G7C01🔗

What circuit is used to select one of the sidebands from a balanced modulator?

使用什么电路从平衡调制器中选择边带之一？

Carrier oscillator

载波振荡器

Filter

过滤器

✓ 正确答案

IF amplifier

中频放大器

RF amplifier

射频放大器

#G7C02🔗

What output is produced by a balanced modulator?

平衡调制器产生什么输出？

Frequency modulated RF

调频射频

Audio with equalized frequency response

具有均衡频率响应的音频

Audio extracted from the modulation signal

从调制信号中提取的音频

Double - sideband modulated RF

双边带调制射频

✓ 正确答案

#G7C03🔗

What is one reason to use an impedance matching transformer at a transmitter output?

在发射器输出端使用阻抗匹配变压器的原因之一是什么？

To minimize transmitter power output

最大限度地减少发射机功率输出

To present the desired impedance to the transmitter and feed line

为发射器和馈线提供所需的阻抗

✓ 正确答案

To reduce power supply ripple

减少电源纹波

To minimize radiation resistance

尽量减少辐射电阻

#G7C04🔗

How is a product detector used?

如何使用产品检测器？

Used in test gear to detect spurious mixing products

用于测试装置以检测杂散混合产物

Used in transmitter to perform frequency multiplication

用于发射机进行倍频

Used in an FM receiver to filter out unwanted sidebands

用于 FM 接收器以滤除不需要的边带

Used in a single sideband receiver to extract the modulated signal

用于单边带接收器提取调制信号

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#G7C05🔗

Which of the following is characteristic of a direct digital synthesizer (DDS)?

以下哪项是直接数字合成器 (DDS) 的特征？

Extremely narrow tuning range

极窄的调谐范围

Relatively high-power output

相对较高的功率输出

Pure sine wave output

纯正弦波输出

Variable output frequency with the stability of a crystal oscillator

具有晶体振荡器稳定性的可变输出频率

✓ 正确答案

#G7C06🔗

Which of the following is an advantage of a digital signal processing (DSP) filter compared to an analog filter?

与模拟滤波器相比，数字信号处理 (DSP) 滤波器具有以下哪一项优势？

A wide range of filter bandwidths and shapes can be created

可以创建各种滤波器带宽和形状

✓ 正确答案

Fewer digital components are required

需要更少的数字元件

Mixing products are greatly reduced

混合产物大大减少

The DSP filter is much more effective at VHF frequencies

DSP 滤波器在 VHF 频率下更加有效

#G7C07🔗

What term specifies a filter’s attenuation inside its passband?

什么术语指定滤波器在其通带内的衰减？

Insertion loss

插入损耗

✓ 正确答案

Return loss

回波损耗

问

Ultimate rejection

最终拒绝

#G7C08🔗

Which parameter affects receiver sensitivity?

哪个参数影响接收灵敏度？

Input amplifier gain

输入放大器增益

Demodulator stage bandwidth

解调器级带宽

Input amplifier noise figure

输入放大器噪声系数

All these choices are correct

所有这些选项都是正确的

✓ 正确答案

#G7C09🔗

What is the phase difference between the I and Q RF signals that software-defined radio (SDR) equipment uses for modulation and demodulation?

软件定义无线电 (SDR) 设备用于调制和解调的 I 和 Q RF 信号之间的相位差是多少？

Zero

零

90 degrees

90度

✓ 正确答案

180 degrees

180度

45 degrees

45度

#G7C10🔗

What is an advantage of using I-Q modulation with software-defined radios (SDRs)?

将 I-Q 调制与软件定义无线电 (SDR) 结合使用有什么优势？

The need for high resolution analog-to-digital converters is eliminated

消除了对高分辨率模数转换器的需求

All types of modulation can be created with appropriate processing

通过适当的处理可以创建所有类型的调制

✓ 正确答案

Minimum detectible signal level is reduced

最小可检测信号水平降低

Automatic conversion of the signal from digital to analog

信号从数字到模拟的自动转换

#G7C11🔗

Which of these functions is performed by software in a software-defined radio (SDR)?

以下哪些功能是由软件定义无线电 (SDR) 中的软件执行的？

Filtering

过滤

Detection

检测

Modulation

调制

All these choices are correct

所有这些选项都是正确的

✓ 正确答案

#G7C12🔗

What is the frequency above which a low-pass filter’s output power is less than half the input power?

在什么频率以上，低通滤波器的输出功率小于输入功率的一半？

Notch frequency

陷波频率

Neper frequency

尼珀频率

Cutoff frequency

截止频率

✓ 正确答案

Rolloff frequency

滚降频率

#G7C13🔗

What term specifies a filter’s maximum ability to reject signals outside its passband?

什么术语指定滤波器抑制通带外信号的最大能力？

Notch depth

缺口深度

Rolloff

滚降

Insertion loss

插入损耗

Ultimate rejection

最终拒绝

✓ 正确答案

#G7C14🔗

The bandwidth of a band-pass filter is measured between what two frequencies?

带通滤波器的带宽是在哪两个频率之间测量的？

Upper and lower half - power

上、下半功率

✓ 正确答案

Cutoff and rolloff

截止和滚降

Pole and zero

极点和零点

Image and harmonic

图像与谐波

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FCC G7C - 实用的电路与原理图

小节 G7C：实用的电路与原理图