Question

1. Name four applications of synthesized sound

2. Name four applications of histogram analysis in image processing systems

3. A speech signal over telephone line contains frequencies from 30 Hz to 4 kHz. Find the maximum sampling interval.

4. A music signal contains frequencies from 20 Hz to 20 kHz. With the Nyquist minimum sampling frequency, find the total number of samples for 10 minutes of music.

Answer 1

sol 1)

Sound synthesis is the technique of generating sound, using electronic hardware or software, from scratch. Sound synthesis has many applications both academic and artistic, and we commonly use synthesizers and synthesis methods to:

• Generate interesting and unique sounds or timbres incapable of being produced acoustically.
• Recreate or model the sounds of real-world acoustic instruments or sounds.
• Facilitate the automation of systems and processes (text-to-speech software, train station P.A.s)
• Digital synthesizer , use technique of DSP

sol 2)

Applications of Histograms

1) We can predict frequency of image by just looking at its histogram. Its like looking an x ray of a bone of a body.

2)The second use of histogram is for brightness purposes. The histograms has wide application in image brightness. Not only in brightness, but histograms are also used in adjusting contrast of an image.

3)Another important use of histogram is to equalize an image.

4) And last but not the least, histogram has wide use in thres-holding. This is mostly   

     used in computer vision.

sol 3)

For minimum sampling frequency fs , we get the maximum sampling interval.

for musical signal, the minimum fs=30Hz.Hence interval Ts=1/fs=0.033s.

sol 4)

The Nyquist rate is twice the maximum frequency of the signal, let fm be the maximum frequency and for given sound signal it is fm=20000Hz. The Nyquist rate is fN=2*fm.

fN=40000samples/second

total number of sample for 10 min is N=fN*600

N=24000000