FCC E8A - 信号处理与发射

#E8A01🔗

What technique shows that a square wave is made up of a sine wave and its odd harmonics?

什么技术表明方波由正弦波及其奇次谐波组成？

Fourier analysis

傅立叶分析

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Vector analysis

矢量分析

Numerical analysis

数值分析

Differential analysis

差异分析

#E8A02🔗

Which of the following is a type of analog-to-digital conversion?

以下哪项是模数转换的类型？

Successive approximation

逐次逼近

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Harmonic regeneration

谐波再生

Level shifting

电平转换

Phase reversal

相位反转

#E8A03🔗

Which of the following describes a signal in the time domain?

以下哪项描述了时域信号？

Power at intervals of phase

相间功率

Amplitude at different times

不同时间的振幅

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Frequency at different times

不同时间的频率

Discrete impulses in time order

按时间顺序的离散脉冲

#E8A04🔗

What is “dither” with respect to analog-to-digital converters?

什么是模数转换器的“抖动”？

An abnormal condition where the converter cannot settle on a value to represent the signal

转换器无法确定代表信号的值的异常情况

A small amount of noise added to the input signal to reduce quantization noise

在输入信号中添加少量噪声以减少量化噪声

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An error caused by irregular quantization step size

量化步长不规则导致的误差

A method of decimation by randomly skipping samples

一种随机跳过样本抽取方法

#E8A05🔗

What is the benefit of making voltage measurements with a true-RMS calculating meter?

使用真有效值计算表进行电压测量有什么好处？

An inverse Fourier transform can be used

可以使用傅里叶逆变换

The signal’s RMS noise factor is also calculated

还计算信号的 RMS 噪声系数

The calculated RMS value can be converted directly into phasor form

计算出的RMS值可以直接转换成相量形式

RMS is measured for both sinusoidal and non- sinusoidal signals

测量正弦信号和非正弦信号的 RMS

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#E8A06🔗

What is the approximate ratio of PEP-to-average power in an unprocessed single-sideband phone signal?

未经处理的单边带电话信号中 PEP 与平均功率的近似比率是多少？

2 . 5 to 1

2. 5比1

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25 to 1

25比1

1 to 1

1对1

13 to 1

13比1

#E8A07🔗

What determines the PEP-to-average power ratio of an unprocessed single-sideband phone signal?

是什么决定了未经处理的单边带电话信号的 PEP 与平均功率之比？

The frequency of the modulating signal

调制信号的频率

Speech characteristics

言语特征

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The degree of carrier suppression

载流子抑制程度

Amplifier gain

放大器增益

#E8A08🔗

Why are direct or flash conversion analog-to-digital converters used for a software defined radio?

为什么软件定义无线电使用直接或快速转换模数转换器？

Very low power consumption decreases frequency drift

极低的功耗可减少频率漂移

Immunity to out-of-sequence coding reduces spurious responses

不受乱序编码影响，减少了杂散响应

Very high speed allows digitizing high frequencies

非常高的速度允许数字化高频

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All these choices are correct

所有这些选项都是正确的

#E8A09🔗

How many different input levels can be encoded by an analog-to-digital converter with 8-bit resolution?

8 位分辨率的模数转换器可以编码多少种不同的输入电平？

8 multiplied by the gain of the input amplifier

8 乘以输入放大器的增益

256 divided by the gain of the input amplifier

256除以输入放大器的增益

256

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#E8A10🔗

What is the purpose of a low-pass filter used at the output of a digital-to-analog converter?

数模转换器输出端使用低通滤波器的用途是什么？

Lower the input bandwidth to increase the effective resolution

降低输入带宽以提高有效分辨率

Improve accuracy by removing out-of-sequence codes from the input

通过从输入中删除无序代码来提高准确性

Remove spurious sampling artifacts from the output signal

从输出信号中去除寄生采样伪影

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All these choices are correct

所有这些选项都是正确的

#E8A11🔗

Which of the following is a measure of the quality of an analog-to-digital converter?

以下哪项是模数转换器质量的衡量标准？

Total harmonic distortion

总谐波失真

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Peak envelope power

峰值包络功率

Reciprocal mixing

相互混合

Power factor

功率因数

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FCC E8A - 信号处理与发射

小节 E8A：信号处理与发射