思科认证考试
Which two statements are true about analog to digital conversion of voice signals for use in digital telephony networks？（）A、The three required steps in the analog to digital conversion are sampling，encoding，and compression.B、The three required steps in th
题目
Which two statements are true about analog to digital conversion of voice signals for use in digital telephony networks？（）
- A、The three required steps in the analog to digital conversion are sampling，encoding，and compression.
- B、The three required steps in the analog to digital conversion are sampling，quantization，and compression.
- C、The three required steps in the analog to digital conversion are sampling，quantization，and encoding.
- D、The output of the sampling process is a pulse code modulation （PCM） signal.
- E、The output of the sampling process is a pulse amplitude modulation （PAM） signal.
相似问题和答案
第1题：
As a network administrator, you will need to decide on the appropriate network devices to use. Which of the following correctly describes the roles of devices in a WAN? (Choose three)
A. A CSU/DSU terminates a digital local loop.
B. A router is commonly considered a DCE device.
C. A modem terminates an analog local loop.
D. A router is commonly considered a DTE device.
E. A modem terminates a digital local loop.
F. A CSU/DSU terminates an analog local loop.
G. A modem is used to terminate a T1
A,C,D
第2题：
Digital data can also be represented by (71)signals by use ofa modem. The modem converts a series of binary voltage (72) into an analog signal by encoding the digital data ontoa carrier frequency. The resulting signal occupies a certam spectrum of (73) centered about the carTier and may be propagated acrossa medium suitable for that carrier. The most common modems represent digital data in the voice(74)and hence allow those datato be propagated over ordinary voice-grade (75 )lines At the other end of the line, another modem demodulates the signal to recover the original data
(71)
A.analog
B.digital
C.Modem
D.electric
数字数据也可以通过调制解调器用模拟信号来表示。调制解调器把数字数据编码为一种载波频率，从而可以把二进制电压序列转换为模拟信号。产生的信号占用了以某一频率为中心的载波频带，可以通过适合于该载波的介质进行传播。大多数通用的调制解调器表示话音频带的数字数据，因而允许这些数据在通常的话音级电话线路上传播。在线路的另一端，另外一个调制解调器对信号进行解调并恢复原来的数据。
第3题：
A.digital-to-analogconversion
B.digital-to-digitalconversion
C.analog-to-digitalconversion
D.analog-to-analogconversion
第4题：
Which three functions are associated with a Cisco Unified CallManager？ （）
- A、 connects traditional telephony devices to voice over IP infrastructure
- B、 converts analog signals to digital format
- C、 performs voice compression
- D、 performs call processing
- E、 performs dial plan administration
- F、 performs signaling and device control
正确答案:D,E,F
第5题：
A.A CSU/DSU terminates a digital local loop.
B.A modem terminates a digital local loop.
C.A CSU/DSU terminates an analog local loop.
D.A modem terminates an analog local loop.
E.A router is commonly considered a DTE device.
F.A router is commonly considered a DCE device.
第6题：
A. Allows for higher brightness
B. More crosstalk
C. Sustains higher resolutions
D. Supports widescreen resolutions
第7题：
A. A CSU/DSU converts analog signals from a router to a leased line; a modem converts analog signals from a router to a leased line.
B. A CSU/DSU converts analog signals from a router to a phone line; a modem converts digital signals from a router to a leased line.
C. A CSU/DSU converts digital signals from a router to a phone line; a modem converts analog signals from a router to a phone line.
D. A CSU/DSU converts digital signals from a router to a leased line; a modem converts digital signals from a router to a phone line.
第8题：
A、its speed
B、its gain
C、the accuracy of the reference voltage
D、the number of binary bits
第9题：
Which statement is true about the capabilities of a voice gateway router？（）
- A、voice gateways with analog interfaces need a gatekeeper to convert analog signals into digital format before voice is encapsulated into IP packets
- B、voice gateways need a gatekeeper to interconnect the VoIP networks the PSTN network
- C、voice gateways with Cisco Unified CallManager Express （CME） can permanently act as a call agent for IP phones
- D、voice gateways equipped with a DSP module can take the role of the call agent during WAN failure.
正确答案:C
第10题：
What is the term that is used to describe the process of converting a signal from digital to analog？（）
- A、 packetization
- B、 quantization
- C、 decoding
- D、 sampling
正确答案:C