Question

A/D-conversion, linear quantization

Graph below shows a one second audio signal

A/D-conversion, logarithmic quantization

Graph shows the same audio signa

Quistion:(comparison of quantization methods)

1,4 V=111- 1,2 V = 110-1 1,0 V = 101- 0,8 V 100 - 0,6 V = 011 | -- 0,4 V = 010 - 0,2 V = 001 tis 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 ext 1,4 V 111- 0,7 V = 110 0,35 V 101 0,175 V = 100 0,088 V = 011 0,044 V = 010 0,022 V = 001 tis o 0,1 0,2 03 0,4 05 0,6 0,7 0,8 0,9 1.0 Comparison of quantization methods Compare quantization methods by coloring the number of leds corespondin to each quantized sample Linear quantization Logarithmic quantization Time L1 L2 L3 L4 L5 L6 7 | |Time | L1 | L2 | L3 | L4 | L5 | L6 | L7 L1 12 L3 L4 LS L6 L7 0,0 s 0,1 s 0,2 s 0,3 s 0,4 s 0,5 s 0,6S 0,7 s 0,8s 0,9 s 1,0 s 0,0 s 0,2s 0,3s 0,4 s 0,5s 0,6 s 0.7s 0,8 8 0,9 S 1.0s Which of the quantization methods is better for a sound level display? Why?

Answer 1

Answer:

I assume L1...L7 here refer to the LEDs indicating the signal level. If that be the case then the behavior of the two displays is shown in the two images below.

LOGARITHHIC o 4 o 0.3 6.6

It is clear from these plots that log ADC represent the speech signal better. Human ear is more sensitive to variations in sound at lower amplitude. Accordingly logarithmic ADC allocates more bits to represent lower amplitude signals as compared to loud sounds.

Hope this helps.