Reading Comprehension

(This passage was written in 1984.)

It is now possible to hear a recording of Caruso's singing that is far superior to any made during his lifetime. A decades-old way-cylinder recording of this great operatic tenor has been digitized, and the digitized signal has been processed by computer to remove the extraneous sound, or "noise," introduced by the now "ancient" wax-cylinder recording process.

Although this digital technique needs improvements, it represents a new and superior way of
recording and processing sound which overcomes many of the limitations of analog recording. In analog recording systems, the original sound is represented as a continuous waveform created by variations in the sound's amplitude over time. When analog playback systems reproduce this waveform, however, they invariably introduce distortions. First, the waveform produced during playback differs somewhat from the original waveform. Second, the medium that stores the analog recording creates noise during playback which gets added to the recorded sounds.

Digital recordings, by contrast, reduce the original sound to a series of discrete numbers that
represent the sound's waveform. Because the digital playback system "reads" only numbers, any noise and distortion that may accumulate during storage and manipulation of the digitized signal will have little effect: as long as the numbers remain recognizable, the original waveform will be reconstructed with little loss in quality. However, because the waveform is continuous, while its digital representation is composed of discrete numbers, it is impossible for digital systems to avoid some distortion. One kind of distortion, called "sampling error," occurs if the sound is sample (i.e.,its amplitude is measured) too infrequently, so that the amplitude changes more than one quantum (the smallest change in amplitude measured by the digital system) between samplings. In effect,the sound is changing too quickly for the system to record it accurately. A second form ofdistortion is "quantizing error," which arises when the amplitude being measured is not a whole number of quanta, forcing the digital recorder to round off. Over the long term, these errors are random, and the noise produced (a background buzzing) is similar to analog noise except that it only occurs when recorded sounds are being reproduced.

1. Which of the following best describes the relationship of the first paragraph to the passage as a whole?
(A) The first paragraph introduces a general thesis that is elaborated on in detail elsewhere in
the passage.
(B) The first paragraph presents a concrete instance of a problem that is discussed elsewhere
in the passage.
(C) The first paragraph describes a traditional process that is contrasted unfavorably with a
newer process described elsewhere in the passage.
(D) The first paragraph presents a dramatic example of the potential of a process that is
described elsewhere in the passage.
(E) The first paragraph describes a historic incident that served as the catalyst for
developments described elsewhere in the passage.

2. According the passage, one of the ways in which analog recording systems differ from digital recording systems is that analog systems
(A) can be used to reduce background noise in old recordings
(B) record the original sound as a continuous waveform
(C) distort the original sound somewhat
(D) can avoid introducing extraneous and nonmusical sounds
(E) can reconstruct the original waveform with little loss inquality

3. Which of the following statements about the numbers by which sound is represented in a digital system can be inferred from the passage?
(A) They describe the time interval between successive sounds in a passage of music.
(B) They model large changes in the amplitude of the initial sound with relatively poor
precision.
(C) They are slightly altered each time they are read by the playback apparaturs.
(D) They are not readily altered by distortion and noise accumulated as the digital signal is
stored and manipulated.
(E) They are stored in the recording medium in small groups that can be read simultaneously
by the playback apparatus.

4. Which of the following can be inferred from the passage about the digital approach to the processing of sound?
(A) It was developed in competition with wax-cyclinder recording technology.
(B) It has resulted in the first distortion-free playback system.
(C) It has been extensively applied to nonmusical sounds.
(D) It cannot yet process music originally recorded on analog equipment.
(E) It is not yet capalbe of reprocessing old recordings in a completely distortion-free manner.

My take:

time: 8:30 mins.

[spoiler]Answers: DEDE[/spoiler]
i guess i got one them wrong, stupid mistake, which i realised while reviewing.

very gmat like passage, whts the source AIM? i liked solved this one.
No notes, just paused between passages to get wht it was saying.

rohu27 wrote:My take:

time: 8:30 mins.

[spoiler]Answers: DEDE[/spoiler]
i guess i got one them wrong, stupid mistake, which i realised while reviewing.

very gmat like passage, whts the source AIM? i liked solved this one.
No notes, just paused between passages to get wht it was saying.

Hey Rohu ,

Great going !!! I didn't attempt this passage before posting , well you are right , it is very GMAT like passage , i loved it partially coz of the intresting subject ... Communication ... while reading the passage i was also wandering about option instead doing MS in Telecommunication .... ohh well holding that thought till i m done with GMAT ... heh .Enough deviation from track .I will post answers in late evening IST , let other members have a take on the post . [spoiler]U did 3/4 right .[/spoiler]

My take on passage :-
Started taking notes but as progressed with passage didnt felt the need of taking notes , relied on comprehension .Mistake i committed is that dont become too excited and dont allow external knowledge to affect the problem solving knack.

IMO DBEE.Time taken : 6 mins

SOurce :- OG 10 , passage should be HARD difficulty one , coz its sequentially at the last , 3rd last passage . I am not sure if OG 10 is also arranged with question of increasing difficulty level.How u felt about the difficulty level of passage ?

Hi Aim, I took 11min for this one..stem is easy but questions are so hard..

Topic : digital vs analog cylinder
adv: noise suppression

para2: digital ++ ; analog--
D > A
Defniton of Analog
disadv of analog

Para3: digital ++
AMR codec
No noise effect

digital -- ; distortion
biterrors - sampling, quantiszion erro

conclusion : Analog = digital if reproduced

1) A/C/E are out B/D.. D>B
2) B (digital vs analog, 2nd par 3rdline)
3) D (third para 3rdline)
4) E (conclusion)

Thanks HSPA , you did really well , as expected . [spoiler]ALL CORRECT , bingo ![/spoiler]

this passage took me back to my engineering days
and AIM you are right, cant allow external knowledge to influence you.
it looks of medium difficulty level but again its of no use predicting all this, i feel.
OG 12 last passages are comparitively much more difficult than this and worse they have like 6-7 questions

IMO: D,B,D,E

OA is DBDE.

Guys let me know if you want official explanation for any of the answers , well we already have 2 100% correct entries i.e HSPA and abhishek . Well done guys .

Hey everyone. Sorry for the late response. Still down with Fever.

Yes Questions were not that easy.

I got D,C,D,E

i got one incorrect, the second one. was a little tricky. The way analog system works it is bound to produce distortions, B is definitely the answer but how did u rule out C.

What could be the scope of the passage and authors point of view?? I felt author was neutral about both the technologies.

Hi force5 ,

Here goes the official explanation for the required question :-

This question asks you to identify something mentioned specifically in the passage that is a feature
of analog recording systems that is not shared by digital recording systems.
Choice B is the best answer. The passage states in lines 10-13 that analog recording systems
represent the original sound as a continuous waveform, while in lines 21-23 it notes that digital
recordings reduce the original sound to a series of discrete numbers. Neither A, D, or E are
features of analog systems, according to the passage. Choice C is not correct: while the passage
does say that analog recording systems distort the original sound, the passage also notes that "it is
impossible for digital systems to avoid some distortion" (lines 31-32). Thus some amount of
sound distortion is involved in both analog and digital recording processes.

I felt the author was neutral and was just conveying the information he had .