1. From which of the following words does codecs is derived?
A. coder
B. decoder
C. coder-decoder
D. coder-encoder
Answer: C
The codec is derived from the coder-decoder and is coupled to perform the coding. It can support both analogs to digital conversion and digital to analog conversion.
2. Which codec is used in digital audio?
A. A-law
B. µ-law
C. linear
D. PCM
Answer: C
In the linear codec, the relationship between the analog and digital values is linear. This method is commonly used in digital audio communication.
3. Which of the following have the same quantization step throughout the range?
A. linear
B. PCM
C. DPCM
D. ADPCM
Answer: A
The quantization step is the same throughout the dynamic range in the linear codec and thus any increase in the analog value increases the digital value, that is, the overall performance is linear.
4. Which is used in telecommunication applications that have a limited bandwidth of 300 to 3100 HZ?
A. linear codec
B. logarithmic codec
C. PCM
D. DPCM
Answer: B
The logarithmic codec is frequently used in the telecommunication system which has a limited bandwidth of 300 to 3100 Hz. this can provide an 8-bit sample at 8 kHz, which is used in the telephones. The commonly used are A-law and µ-law.
5. Which codec is used in the UK?
A. a-law
B. µ-law
C. linear codec
D. PCM
Answer: A
The a-law is a logarithmic codec that is commonly used in the UK whereas the µ-law is used in the US.
6. What does PCM stand for?
A. pulse codec machine
B. pulse code modulation
C. peripheral code machine
D. peculiar code modulation
Answer: B
The linear codec is also known as pulse code modulation which is commonly used in the telecommunications industry.
7. Which of the following conversion is performed by using a lookup table?
A. DPCM
B. ADPCM
C. Between DPCM and ADPCM
D. Linear codec and a-law
Answer: D
The conversion between a-law/µ-law and a linear digital signal or between µ-law and a-law is performed by a lookup table.
8. What does DPCM stand for?
A. differential pulse code modulation
B. data pulse code modulation
C. dynamic pulse code machine
D. dynamic pulse code modulation
Answer: A
The differential pulse code modulation is similar to pulse code modulation, but DPCM uses an encoded value which is the difference between the current and the previous sample.
9. Which of the following have a 16-bit digital dynamic range?
A. PCM
B. DPC
C. linear codec
D. logarithmic codec
Answer: B
The differential pulse code modulation can improve the accuracy and resolution by having a 16-bit dynamic range. It works by the increasing dynamic range.
10. How many types of logarithmic codecs are used commonly?
A. 2
B. 3
C. 4
D. 5
Answer: A
There are two types of logarithmic codecs that are commonly used. They are a-law which is used in UK and µ-law codec which is used in the US.
