1. Sound (analogue signal)

2. time

3. Sound (analogue signal) time

4. Sound (analogue signal) time

5. Sound (analogue signal) time

6. Sound (analogue signal) time

7. Sound (analogue signal) time

8. Sound (analogue signal) time

9. Sound (analogue signal) time

10. Sound (analogue signal) time

11. Sound (analogue signal) time

12. Sound (analogue signal) time

13. Sound (analogue signal) time 11011101 (=221) 1111110101011101 1101110110011101011011010101110111011110 221

14. Real Sound (analogue signal) time 11011101 (=221) 1111110101011101 1101110110011101011011010101110111011110 221 The sampling give the red signal

15. A song last for 2 minutes and 40 seconds. If the music is sampled at 30 Kh with a sampling resolution of 16 bits, calculate how much capacity (in megabytes) would be needed to store the file. Number of samples = 160 X 30000 = 4800000 samples Size of file= 4800000 X 16 bits = 4800000 X 2 bytes = 9600000 bytes = 9375 Kb = 9.155 Mb (3 dp)

16. Data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an unencoded representation would use through use of specific encoding schemes. For example, this article could be encoded with fewer bits if one were to accept the convention that the word "compression" be encoded as "comp." One popular instance of compression with which many computer users are familiar is the ZIP file format, which, as well as providing compression, acts as an archiver, storing many files in a single output file.bitsunencoded encodingZIP file formatarchiver Data compression As with any communication, compressed data communication only works when both the sender and receiver of the information understand the encoding scheme.senderinformation Compression is useful because it helps reduce the consumption of expensive resources, such as hard disk space or transmission bandwidth. On the downside, compressed data must be decompressed to be viewed (or heard), and this extra processing may be detrimental to some applications. For instance, a compression scheme for video may require expensive hardware for the video to be decompressed fast enoughhard diskbandwidth Lossless compression does not lose any detail. Lossy may lose some detail in the transmitted data – but it may not be all that important. An example of lossless vs. lossy compression is the following string: 8888888333333333 This string can be compressed as: 8[7]3[9]. Interpreted as, “7 eights, 9 threes", the original string is perfectly recreated, just written in a smaller form. In a lossy system, using 83 instead, the original data is lost, at the benefit of a smaller filesize.

17. Stored in the MIDI is a vast bank of standard waveforms. The software uses an algorithm to select a sample from the bank. The selected waves are combined to approximate (closely) to the required sound. MIDI (Musical Instrument Digital Interface)

18. The End